View Full Version : Nick G modified Lentek Head Amp
Guys,
I mentioned a while back that I was going to get my Lentek tweaked by Nick (to use with my DL-103), and now it's finished.
Nick's just sent me some pics, so here they are (with new output cables, plugs and phono sockets):
http://img227.imageshack.us/img227/3109/dscf0060z.jpg (http://img227.imageshack.us/i/dscf0060z.jpg/)
Close up of new phono sockets:
http://img163.imageshack.us/img163/6778/dscf0062s.jpg (http://img163.imageshack.us/i/dscf0062s.jpg/)
Internal components, showing extensive capacitor changes:
http://img232.imageshack.us/img232/1341/dscf0063i.jpg (http://img232.imageshack.us/i/dscf0063i.jpg/)
Close-up of internal components:
http://img600.imageshack.us/img600/9292/dscf0065p.jpg (http://img600.imageshack.us/i/dscf0065p.jpg/)
And again:
http://img221.imageshack.us/img221/7175/dscf0066t.jpg (http://img221.imageshack.us/i/dscf0066t.jpg/)
And just for comparison purposes, this is what a standard unit looks like inside (taken from DSJR's Lentek Naked thread):
http://img594.imageshack.us/img594/8881/dscf1456m.jpg (http://img594.imageshack.us/i/dscf1456m.jpg/)
For reference, the component changes, wire and plugs in mine are as follows:
Ceramics were replaced with Wima FKP polyprop caps. Tants were replaces with OSCON SA caps.
The RCA sockets are CMC gold plated RCA sockets from HFC and the plugs are CMC-1036-WF RCA plug also from HFC. Cable is Shark double screened cable.
I'm picking it up tomorrow, so it'll be interesting to hear what it sounds like now... :)
Full report to follow!
Marco.
Guys,
I mentioned a while back that I was going to get my Lentek tweaked by Nick (to use with my DL-103), and now it's finished.
Nick's just sent me some pics, so here they are (with new output cables, plugs and phono sockets):
http://img227.imageshack.us/img227/3109/dscf0060z.jpg (http://img227.imageshack.us/i/dscf0060z.jpg/)
Close up of new phono sockets:
http://img163.imageshack.us/img163/6778/dscf0062s.jpg (http://img163.imageshack.us/i/dscf0062s.jpg/)
Internal components, showing cap and resistor changes:
http://img232.imageshack.us/img232/1341/dscf0063i.jpg (http://img232.imageshack.us/i/dscf0063i.jpg/)
Close-up of Internal components:
http://img600.imageshack.us/img600/9292/dscf0065p.jpg (http://img600.imageshack.us/i/dscf0065p.jpg/)
And again:
http://img221.imageshack.us/img221/7175/dscf0066t.jpg (http://img221.imageshack.us/i/dscf0066t.jpg/)
I'm picking it up tomorrow, so it'll be interesting to hear what it's like now... :)
Full report to follow!
Marco.
Hi Marco,
Gosh! It looks a bit of a "dog's dinner", but one shouldn't judge a book by it's cover as they say.
I've completely given the EMT TSD15/adapter a completely new set up. I had to change the arm-board so that I could move the SME arm base to the end of the bedplate keyway. The overhang is now correct, before it was significantly out.
The reason why I'm bringing this up is that believe you are intending to use your modified Lentek (how has it been modified?) with the EMT. At the moment I'm running it directly into a MM input of 1mV senstitivity and 47KOhm impedance with excellent results. Will try it with a 20x Nakamichi SUT before I send it off to you.
Regards
Hi Barry,
Dog's dinner... Dogs dinner??? Wash thy mouth out, heathen! ;)
Remember Nick's had to squeeze much bigger components than were there before (not to mention thicker cable) into a tiny area, and it was never 'tidy' inside it to start with......!
Anyway, it looks fine with the cover on it. How it sounds now, anyway, is what matters most :)
The reason why I'm bringing this up is that believe you are intending to use your modified Lentek (how has it been modified?) with the EMT.
As per pics above. Not sure exactly what you mean by that, and why you're telling me about arm boards, etc, when I won't be able to do that on the Techie :scratch:
The Lentek head amp will match the EMT (as did the A23 SUT), as the EMT has similar electrical requirements to the DL-103, so it should sound great as a combo :cool:
Marco.
Here's a pic of the unit when I bought it in its box (observe the crappy output cable and plugs! :spew:):
http://img843.imageshack.us/img843/7747/lentekpreamp.jpg (http://img843.imageshack.us/i/lentekpreamp.jpg/)
And a pic of the inside of the unit as standard, courtesy of Dave (DSJR):
http://img181.imageshack.us/img181/360/dscf1358.jpg (http://img181.imageshack.us/i/dscf1358.jpg/)
Inside that little black box on the right is where the 'gubbins' is, and there's not a lot of space to try and work inside!
Marco.
Not sure exactly what you mean by that and why you're telling me about arm boards, etc, when I won't be able to do that on the Techie
I was wondering if some component values had been changed,as well as component quality.
Apropos changing the arm board - I wanted to make quite sure the cartridge was operating under ideal conditions in my arm before I sent it off for you to hear it. Before changing the armboard the overhang was badly out; I couldn't hear any distortion, but had to put it right for my own piece of mind.
Regards
Oscons and FKP's, thats definitely going to sound different to the stock unit
Ah, no worries, Barry..... :)
As for component values being changed, I'm not sure, you'll have to ask Nick. He's usually lurking around, so he may comment :cool:
Marco.
Oscons and FKP's, thats definitely going to sound different to the stock unit
Hi Leo,
In roughly what way, in your experience? :)
Marco.
Warmer as a guess, more colour. I don't use Oscons in analogue circuits and don't know the Lentek circuit so can't say for sure how it will sound. Nick knows his stuff so they probably mate well with the Lentek.
Oscons are low esr and can be useful in some digital circuits for supply decoupling. I'd imagine a very different flavour to tants when used in analogue circuits. Those Wima polypropylenes should be smoother in the high's than microphonic ceramics if used in say a LPF.
Give it a good running in, Oscons usually require longer than normal caps, they can sometimes be DC leaky when new too which usually goes away after plenty of burn in. Be interesting to hear how you find it
Hi Leo,
Sounds interesting....
The Lentek was a little 'grainy' sounding before and had a rather 'grey' tonal palette. It also gave a somewhat hard edge to vocals, along with its infectious and 'peppy' musical presentation, with bags of rhythmic drive in the bass (when used in conjunction with a DL-103).
So the possible changes you describe could prove to be an asset :)
Marco.
Grey and Grainy is typical with stuff filled with tants and ceramics (I won't mention any names ). Obviously analogue circuits are different to digital, analogue components used like caps is usually tuned by ear if used in say coupling, the hard bit is making sure you don't go too far overdoing it . I've heard some people find the bass can be a little soft with too many low esr caps in the chain, anyway good luck and keep us posted :)
Looking forward to your report Marco I remember hearing it before being mod it showed potential but agree with Marco thoughts The first words I said were it be worth getting this mod of course Marco already had plans that way
Hi Leo,
Grey and Grainy is typical with stuff filled with tants and ceramics (I won't mention any names ). Obviously analogue circuits are different to digital, analogue components used like caps is usually tuned by ear if used in say coupling, the hard bit is making sure you don't go too far overdoing it . I've heard some people find the bass can be a little soft with too many low esr caps in the chain, anyway good luck and keep us posted...
I think you're spot on, mate.
I suspect that Nick has used his experience to 'voice' the Lentek in a way that will make it sound more musical and less 'hi-fi'. It's a difficult balancing act to achieve, and shows yet again how one cannot build or modify equipment using measurements alone.
Trained and experienced ears are the order of the day.
As long as the Lentek hasn't lost its PRAT and 'boogie factor', which is why it complimented the 103 so well, I'll be happy :)
Marco.
Hi John,
Looking forward to your report Marco I remember hearing it before being mod it showed potential but agree with Marco thoughts The first I said it be worth getting this mod of course Marco already had plans that way
I'll definitely write something up once all the caps have burnt-in and the sound of the unit has 'fleshed out'.
The market isn't exactly flooded with good quality head amps, particularly ones that match the very popular DL-103 so well, so if the mods prove to be successful, my recommendation for people will be to buy a Lentek second-hand on Ebay, and have it modified. It'll be another viable option to explore.
Therefore, for around £150 one could have a top-notch active 'MC step-up solution' to rival the SUT approach that's likely to be superior to the built-in active MC stages in most commercial budget to 'almost affordable' preamps and phono stages, particularly for those who want to max-out the 103's unique sonic attributes... :)
Besides, I just LOVE using 'race-tuned', bespoke, hi-fi components and taking a different path from the norm! :eyebrows:
Marco.
Just so you all know, the reason its a bit "untidy" is that the entire thing is potted in silicon, so it had to be dug out before working on it. As said, I replaced the ceramics without thought, as I rarely find they deserve a place in the audio chain. The FKP I agree tend to be warm, but IMHO thats a good thing when combined with a unit what was a little hard sounding to my ears to start. The oscons were a experiment, In the past I would have used little black gates, and it possible I still will, see how Marco gets on, but it was the low noise character that I was most interested in.
TBH, it is noisier than I would have hoped for anyway, I have a thought to try something with a couple of 2sk369 in each chan.
Grainy and grey? Not what you said when I complained of the same thing..... hmphh :lol:
Seriously though, the main problem with the supplied wires is age, rather than weakness and the phono plugs were ok, although not very posh looking (mine weren't original anyway).
I do feel a cap change coming on with mine though, although i wouldn't go with the aggro in changing all the resistors, let alone trying to shoehorn huge transistors in (what is deemed to be inadequate in the originals please?). I'm genuinely interested, not being sarcastic or critical, as regarding the caps, I suspect Lentek used what was available and of good consistent quality for the times.
Perhaps a parts-list please????????? :)
I look forward to reading the auditioning results while I plan world domination via Sowter instead (A23 is too dear and I have a box socketed up in readiness for the Sowters) :)
Hi Dave,
Grainy and grey? Not what you said when I complained of the same thing.....
I should've said 'grainy and grey' in comparison to the (£550) A23, when I originally tested them together ;)
Look, as standard, for about £60 second-hand on Ebay, it's astonishingly good with a DL-103. However, as ever with anything in audio, things can be improved.
Seriously though, the main problem with the supplied wires is age, rather than weakness and the phono plugs were ok, although not very posh looking (mine weren't original anyway).
Similar to electrical components, Dave, the quality of plugs and cables has come a long way since the 80s. The stock items are distinctly poor by today's standards, and so needed replaced.
I do feel a cap change coming on with mine though, although i wouldn't go with the aggro in changing all the resistors, let alone trying to shoehorn huge transistors in (what is deemed to be inadequate in the originals please?). I'm genuinely interested, not being sarcastic or critical, as regarding the caps, I suspect Lentek used what was available and of good consistent quality for the times.
Re: the bit in bold. Did you mean caps or resistors instead, or am I misunderstanding you?
Nick will I'm sure explain why these were changed. Yes, Lentek would've used what was available at the time of decent quality, but remember that the quality of components these days, compared to those from nearly 30 years ago is more often than not far superior, so it's a no-brainer to upgrade the rather aged stock items.
Perhaps a parts-list please?????????
Did you miss this bit, daftee:
For reference, the component changes, wire and plugs in mine are as follows:
Ceramics were replaced with Wima FKP polyprop caps. Tants were replaces with OSCON SA caps.
The RCA sockets are CMC gold plated RCA sockets from HFC and the plugs are CMC-1036-WF RCA plug also from HFC. Cable is Shark double screened cable.
;)
I look forward to reading the auditioning results while I plan world domination via Sowter instead (A23 is too dear and I have a box socketed up in readiness for the Sowters)
First impressions will likely be posted sometime tomorrow :cool:
Marco.
Hi Nick,
Just so you all know, the reason its a bit "untidy" is that the entire thing is potted in silicon, so it had to be dug out before working on it.
Yes indeed - obviously they didn't really want it to be opened up!
As said, I replaced the ceramics without thought, as I rarely find they deserve a place in the audio chain. The FKP I agree tend to be warm, but IMHO thats a good thing when combined with a unit what was a little hard sounding to my ears to start.
I agree, and I like your thinking on this :)
The oscons were a experiment, In the past I would have used little black gates, and it possible I still will, see how Marco gets on, but it was the low noise character that I was most interested in.
Sure, mate, I'll live with it for a while 'as is' and let everything burn-in. If I think there's mileage in more tweakery, I'll let you know, and you can vandalise it further :eyebrows:
TBH, it is noisier than I would have hoped for anyway, I have a thought to try something with a couple of 2sk369 in each chan.
Like I said, it was 'noisy-ish' (read as in comparison to the A23) when I had it, although I never found this intruded on the type of music I played that suited its sonic characteristics (rock and pop), so if it's the same in that respect (or perhaps slightly better) but superior overall sonically, I'll be more than happy!
If you feel a couple of 2sk369s in each channel is liable to reduce noise, then that's something I'd be happy for you to fit as soon as possible, so if you've got any kicking around, feel free to pop them in before you bring the Lentek round ;)
See you later, dude! :cool:
Marco.
I'm going sight-fuzzy as well as deaf Marco :D so need the component list spoon-fed me. Caps I'm prepared for, as long as I can get the correct values (I like Wimas) Transistors I may well leave alone as long as the supplied ones aren't so poor (I doubt it). The cables already there look to be good quality screened ones and mine still had reasonable looking conductors. I do like the Shark wires though (their silver plated cable made excellent interconnects without sounding "silvery" to me, but that's another story).
By the way, mine wasn't potted, so I was lucky for once. The cap was super-glued (or similar) in place, so the board is a doddle to lift in my sample.
I'm not looking for the nth degree here, just a modernised old classic with a little less "character."
Would Mr Lurcher have tried it with a decent low impedance/noise power supply? Mine was too "hummy" for proper use and I might just change the 1000uF caps therein for some bigger ones. I have no idea until I've done it whether it'll make any difference. Pics to follow..
I left it on battery, I think it would be hard to get a low noise supply that was floating in the way a battery does.
I didnt change the transistors thats what I found under the silicon, I suspect they may be the same types BD380 (I think, the numbers were rubbed off) just different case.
Hi Nick,
Remember we were talking yesterday about you adding some components to the Lentek to reduce noise?
It was this comment of yours earlier I was referring to yesterday:
TBH, it is noisier than I would have hoped for anyway, I have a thought to try something with a couple of 2sk369 in each chan
That's what I was on about.
If the 2sk369s simply reduce noise, without affecting the sound much, then that's something I'd like to try soon - or am I misunderstanding you and that these are fitted to something else other than the Lentek?
If that's the case, is there anything you could do to the circuit in the Lentek to make it less noisy, without starting again from scratch?
Btw, I haven't listened to it yet :)
Marco.
I left it on battery, I think it would be hard to get a low noise supply that was floating in the way a battery does.
I didnt change the transistors thats what I found under the silicon, I suspect they may be the same types BD380 (I think, the numbers were rubbed off) just different case.
I wonder if mine could be later - may explain the lack of potting compound...
I look forward to developments with interest :)
Hi Nick,
Remember we were talking yesterday about you adding some components to the Lentek to reduce noise?
It was this comment of yours earlier I was referring to yesterday:
That's what I was on about.
If the 2sk369s simply reduce noise, without affecting the sound much, then that's something I'd like to try soon - or am I misunderstanding you and that these are fitted to something else other than the Lentek?
If that's the case, is there anything you could do to the circuit in the Lentek to make it less noisy, without starting again from scratch?
Btw, I haven't listened to it yet :)
Marco.
Its me not explaining whats going on in my head, sorry. I meant a new circuit, not part of the existing one. I think the Lentek is what it is, can't think of any obvious was of making it quieter.
--
Nick
ourdogmax
15-11-2010, 15:22
Hi Guys, does anybody have the schematic for the lentek, at all, pretty please.....:cool:
I can re-post my pics to see of you can make sense of it all. You'll have to study hard to draw it out, but here goes...
http://i132.photobucket.com/albums/q8/DSJR_photos/DSCF1460.jpg
http://i132.photobucket.com/albums/q8/DSJR_photos/DSCF1456.jpg
The first one's pretty cr@p I admit. I'll try to dismantle it again and take a better photo of the print side...
ourdogmax
15-11-2010, 17:33
Thank's Dave. to be honest I can't make head or tail of it, unless it's a schematic I'm knackered. :lolsign:
Reid Malenfant
15-11-2010, 17:36
I threatened to create a schematic of the circuit previously. Just need a nice straight & clear shot of the rear of the PCB & it should be possible...
I will be interested to hear your thoughts Marco.
I've had one of these for years (1983 or so) the last time I tried it can't say I was overly enamoured (it was with a 103 rather than 103R IIRC).
Anyway happy to did it out and try, I always liked the idea of active with a battery.
Marco mentioned £60 on ebay - seen them go for £80 more recently.
Real shame as they would go for nearer £20 sell as recently as the beginning of the year - crazy how these things suddenly happen with the Internet <-> Ebay feedback loop.
Personally that puts them out of range for me for trying out as there are other things out there with better perceived value - the Sondex DE1 I recently sold for less than twice that is much more substantially built and with more flexiblity and importantly sounds fantastic and probably no need to do the upgrades either as it was all premium parts in the first place.
My whole recently purchased valve pre with dual volume controls and phono stage, full of Mullards was less than one Lentek battery, 4x transistor head amp. A lucky purchase perhaps (and don't yet know if it works) but just goes to show how prices become skewed.
Marco mentioned £60 on ebay - seen them go for £80 more recently.
Real shame as they would go for nearer £20 sell as recently as the beginning of the year - crazy how these things suddenly happen with the Internet <-> Ebay feedback loop.
Personally that puts them out of range for me for trying out as there are other things out there with better perceived value - the Sondex DE1 I recently sold for less than twice that is much more substantially built and with more flexiblity and importantly sounds fantastic and probably no need to do the upgrades either as it was all premium parts in the first place.
My whole recently purchased valve pre with dual volume controls and phono stage, full of Mullards was less than one Lentek battery, 4x transistor head amp. A lucky purchase perhaps (and don't yet know if it works) but just goes to show how prices become skewed.
Got one here I don't use. Anyone want it for £25 plus postage?
Don't ask why, but i've been looking at 1960's record-players recently.. I sold my Hacker GP42 at auction eight years ago and got a fiver for it :( Now they're nearer £100 in good nick. This is nothing compared to any old s**t with "Dansette" stuck on the box. Working ones of almost any model go for £100 or often far higher. Hell, the little Green-Shield Stamp special "Popular," which was my first ever personal record player fetches a ton or so. I wouldn't pay a tenner for it TBH..
http://i132.photobucket.com/albums/q8/DSJR_photos/dansettepopular.jpg
Dave Hewitt
16-11-2010, 17:21
Hi
I will have your head amp if its not gone, Dave.
Lol - what are you going to do with it, Dave? I didn't think you used a turntable :)
Marco.
Hi
I will have your head amp if its not gone, Dave.
Not gone m8. And Im not far from you near Wigan.
I'll check it over.
PM me with details and we'll get together for a handover.
Dave Hewitt
16-11-2010, 17:50
Thanks Dave,get back to you later.
Dave Hewitt
16-11-2010, 17:55
Hi Marco
Didnt you know I have several turntables including Technics direct drive and arotel direct drive plus lenco idler drive and a homemade belt driven one.We have record players in England as well you know.
Cheers Dave.;)
Hahaha... Aye, indeed! I didn't think you used the ones you've got, though. I stand corrected :)
Enjoy the Lentek, if you get it, and if you'd like to hear it with a 103 (unless you have one already), just let me know :cool:
I've still to listen to my Lentek, since Nick's modified it - too busy enjoying what the copper amp's doing with my CDP and the SPU on my Techie now the amp is back with me. You must pop round and hear the difference the repairs/mods have made. I think you'd like it :eek: :wow:
Marco.
I've no idea if these pics will help someone to draw out the board, but here goes...
http://i132.photobucket.com/albums/q8/DSJR_photos/96ba2a2e.jpg
http://i132.photobucket.com/albums/q8/DSJR_photos/bda98abb.jpg
These are the best I can do. Good luck to anyone wishing to mod one. I know I had a little fun with Marco over it, but it's not bad at all, even in standard form.
P.S. I wonder if some of these very thin caps were chosen simply because they were thin?
Reid Malenfant
17-11-2010, 17:01
I've no idea if these pics will help someone to draw out the board, but here goes...
http://i132.photobucket.com/albums/q8/DSJR_photos/96ba2a2e.jpg
http://i132.photobucket.com/albums/q8/DSJR_photos/bda98abb.jpg
These are the best I can do. Good luck to anyone wishing to mod one. I know I had a little fun with Marco over it, but it's not bad at all, even in standard form.
P.S. I wonder if some of these very thin caps were chosen simply because they were thin?
Should be good enough Dave ;)
Most ceramic caps are pretty thin, i somehow doubt it was much of a consideration when building it. Plenty of other caps out there that'd fit in those spaces..
I'll copy the pics & attempt to draw it out when i have some free time :eyebrows:
Oh bloody hell, where do I start? This thing sounds f*cking AMAZING now...!!! :stalks: :eek: :wow:
Ok, I guess at the beginning is a good place...
As I said earlier, in my opinion, the Lentek (in conjunction with a DL-103) excels with rock and pop music. I particularly like listening to it with my large collection of 80s 12" singles, as its peppy, energetic and rhythmically adroit presentation propels music along in a tremendously addictive fashion, putting a big grin on your face.
I've been used to listening on headphones recently, due to my copper amp being away for repair, and find it a very good way of assessing changes made to equipment through my (fairly) sonically transparent headphone amp and AKG 701s, as one can eliminate significant negative influences on the sound, such as the room, for starters!
So I cued up 'Drive' by the Cars, and turned the headphone amp up to the normal level used when I had the Lentek before it was modified, and lowered the stylus into the groove....
When the opening bass line kicked in, it nearly took my head off (!) such was its sheer attack, power and intensity, making the music seem subjectively louder than before. Bass is significantly more extended, weightier, and with superior rhythmic 'snap', and so consequently music listened to is driven along with great purpose, when of course the programme material demands, and with this being beat-driven pop music, it most certainly qualified!
Vocals are crisper sounding, but less sibilant, and are projected with greater expression and definition, losing the sheen, grainy inflection and tonally grey character they had before, and the top end is both sweeter sounding and less 'transistor like', taking on an almost valve-like shimmery sparkle.
The noise floor, whilst still greater than that of a good SUT, is much lower than before, and so consequently one is now more able to concentrate on the musical content of recordings, without being distracted by hiss. Hiss is not an issue now in any real sense unless one is a big fan of choral or light classical music, where noise during quiet passages may be an issue, and if so, a DL-103 is unlikely to be used as one's chosen cartridge - and nor would one likely use a Lentek.
What Nick has managed to achieve through judicious choice of replacement components is ameliorate the undesirable qualities of the Lentek in stock form and maximise its musically infectious traits, making it an absolutely thrilling listen with rock and pop music, using a DL-103, through a quality MM phono stage. Valve phono stages, with their generally more extended tonal palette and 'cleaner' top end, are likely to make the most of its particular sonic attributes.
I must stress that the results obtained are with a Denon DL-103. Similar results with other cartridges cannot be guaranteed.
However, make no mistake, thus modified, the Lentek head amp is in my opinion one of the best MC step-up solutions I've heard at anything like the price, and unquestionably the best device to my ears for optimising the sonic performance of a DL-103, trumping the (£550) A23 SUT in terms of visceral impact and dynamics, if not in ultimate subtlety and finesse with gentler types of music.
If you love the DL-103, and your record collection contains a healthy selection of rock and pop/dance/electronic music, you owe it to yourself to track down a Lentek from Ebay and have our resident genius from Halifax breathe his magic on it, as quite honestly, the results are staggering!
Well done, Nick, you're a star! :cool:
Marco.
Please can Mr Lurcher provide a component list (and the best place to get the bits), or if he has spares, take pity on an impoverished audiophool and sell the bits at a fair price????????
Thanks in advance...
Reid Malenfant
17-11-2010, 20:53
Please can Mr Lurcher provide a component list (and the best place to get the bits), or if he has spares, take pity on an impoverished audiophool and sell the bits at a fair price????????
Thanks in advance...
Dave, i offered you Sanyo Oscons (which i believe were the tant replacements) for nothing ;) They are still here....
:lolsign:
Oh yes, thanks very much. You know the values needed? PM on its way..
Seems like Nick does his magic again It can only get better as still burning in I imagine
Cool, glad it works.
The bits I used were:
From www.rapidonline.com
47uF 6.3V OSCON SA Electrolytic Capacitor 4 off Part # 11-2508
47u 10V OSCON SC Electrolytic Capacitors 2 off Part # 11-2522
From www.rswww.co.uk
Radial polyprop cap,2.2nF 100V 2.5mm 2 off Part # 247-0271
Radial polyprop cap,10nF 100V 2.5mm 3 off Part # 247-0300
I don't have enough left to make up a set of all the bits, but if you can't get any of them, let me know and I will add them to the next order I send to them both for you.
The connectors used were from HiFi Collective
CMC gold plated RCA sockets one pair
CMC-1036-WF RCA plug one pair
Not forgetting of course the excellent Shark interconnect cable... ;)
Yes it does work - and how! :eek: Btw, I really like those lockable CMC RCA plugs!
John, yes no doubt things are still burning in, but even right now the results are sublime....
I'm not sure that after this I want to go back to my SPU!!
Marco.
Thanks to all for the excellent info. I do have a domestic account with RS, but have to pay a fiver postage - same with Rapid (would cost more in diesel to travel and park to/in Colchester).
Marco, I'm going to leave my interconnect alone for now. The cable in mine still has bright shiny copper on a tiny bit of exposed inner core and the screen wires look very good too. The dialectric is a foamed poly-whatever and I always found it good in the full-length versions we sold at the time. Not disputing the quality of the Shark though, their silver plated cable (still available I believe) was excellent I remember and nothing like a "typical" silver-plated copper wire.
No problem, Dave.
I doubt that I'd bother in your position either. The difference is that I had the original cable and plugs on mine, which were pretty horrid, so replacing them with something better was a no-brainer.
Good luck with the mods - keep us posted on how you get on. I was up until 3am this morning listening to music, so that's testament to how good the Lentek gets when modded as described! :)
Marco.
John, yes no doubt things are still burning in, but even right now the results are sublime....
Well, the new components in the Lentek have had a chance now to burn-in, and needless to say things have improved further, with the sound now 'fleshing out', losing a slight hard edge (simply due to the newness of the caps, etc), and gaining more weight, body and finesse.
The sonic balance now of the Lentek, with the DL-103 through my Croft preamp's valve MM stage, is just right and music is utterly beguiling to listen to. There's an addictive rhythmic flow and 'impetus' with the Lentek that makes rock, pop and dance music boogie along in a thrilling 'edge of the seat' way that escapes the A23, or indeed any step-up transformer I've heard with the DL-103.
The Lentek, thus modified, takes the performance of the Denon to new levels and really shows what this cartridge is capable of when optimally partnered and everything is working in its favour - and that means the use of a high-mass headshell (Ortofon LH-9000 at 16.8g) and a 'classic' tonearm such as the Jelco SA-750.
Quite frankly, the modded Lentek successfully addresses the weaknesses of the 103 in a way I've never heard before, as the openness and clarity in both the midrange and top-end registers is such that one would struggle to guess that a spherical tip was in use, and the sheer drive and extension of the bass with suitable material takes your breath away.
It's testament to how good vinyl replay is in my system at the moment with the Lentek and DL-103 that I'm in no great hurry to return to my SPU/A23 combo, although I suspect that when I do, I'll be reminded of the rather unique and desirable traits of that particular combo - hey, I guess that's the fun of owning more than one cartridge! :)
Next up will be to try Barry's superb EMT TSD-15, with a fine-line stylus, using an Ortofon adapter for the Jelco, which is another broadcast cartridge I've always rated and wanted to hear properly in my system.
The Decca London Gold of Barry's was also a thrilling listen, with unique musical abilities that no other cartridge I've heard has, the same of which can be said of the SPU and the DL-103, when partnered with my modified Lentek head amp.
Those are the sorts of cartridges that to my ears make music make sense, and are miles away from the sound of many clinical, tonally bleached and musically bland monstrosities, posing as cartridges, foisted upon us nowadays!
Considering that the design of all the above cartridges harks from a bygone era, where has modern cartridge design gone wrong, I wonder?
Marco.
Jimmy H used an EMT with VDH tip for a while and i found, at the time, it to be a little straight laced and "correct" in an objective sense. It'll be interesting to see and hear how it copes with modern sources and step-ups..
I wonder if my Koetsu Black is repairable (it's lost a channel)? When working it sounded sublime, with weight but no bloat and life without any harshness....
Rare Bird
21-11-2010, 13:52
Gosh! It looks a bit of a "dog's dinner"
:lolsign:
Hi Dave,
Jimmy H used an EMT with VDH tip for a while and i found, at the time, it to be a little straight laced and "correct" in an objective sense.
Yes I remember you making that comment before about the EMT, but if that's true, then I doubt Barry would've bought it, as that type of presentation isn't really his thing (or mine), but we shall see what happens when I strap it onto the Jelco.... :)
I had a Koetsu Black Goldline (a modern one, not one of Sugano's originals) and used it with the last LP12 I owned (on a Hadcock GH242 Integra) shortly before I discovered the joys of direct-drive done well, and it never really did it for me, sounding rather bloated and 'plummy', but with curiously also a distinct treble emphasis.
I put it down to the deck and/or arm not suiting it, or perhaps the Graham Slee phono stage I was using it with at the time (Reflex MM with Elevator EXP MC head amp), so I would love to revisit the Koetsu thing, this time on a much more neutral T/T and set-up.
Your thoughts on the question I asked at the end of my last post would be interesting :cool:
Marco.
Andre - lol!
I think Nick explained the reasons for that, but who cares what it looks like inside when you don't see it, and it sounds so bloody wonderful!?? ;)
Marco.
Indeed, dude - each to their own :)
But there wasn't an awful lot of room inside the Lentek to have made things much neater.... And remember also what Nick said:
Just so you all know, the reason its a bit "untidy" is that the entire thing is potted in silicon, so it had to be dug out before working on it.
Indeed, and so no way would any gear Nick's made himself from the ground up look like that inside!
Marco.
Where you & me differ then ;)
Out of interest (mine) if you had two similar bits of kit, one was full of a rats nest of wires, the other had all the wires at right angles tie wrapped into neat bundles. Which would you prefer?
if you then found the rats nest one sounded better because of the reduced inter-wiring capacitance and crosstalk, what would you think and prefer then?
I am not suggesting that this is the case with this headamp, it is what it is, but in general hearing with your eyes intrigues me.
I quite like the modified naim way in the 82 preamp - wires neatly routed but now without cable-ties so they are lightly separated from each other. I not that Glenn Croft is now using screened wires inside his current range, unlike the .6mm "telephone" wire he used in mine. The only crosstalk I get is from radio to CD and that's ok 'cos I turn the tuner off when not in use...
Marco, please remember that my memories of the EMT, together with my sample of Koetsu Black, are mid 1980's, and a heck of a lot has gone on since then, hence my comments about the EMT with more modern loading ideas and tonearms/turntables etc. When the 'Black was working properly, it had an almost Decca like sense of "presence" with real weight and timbre-rendition in the bass. The treble region was clean and surface noise very low indeed - and this was in the Dual 701!!!!!!!!!!!!! The Black "S" which replaced it had more sparkle and compared really well with the then dearer Troika. After this, Koetsu prices went even higher through the roof and the constant plugging by Martin Colloms and KK, IMO "playing to the converted," took them into the deluxe-cachet bracket, which I still don't think they entirely deserved..
Anyway, I'm really glad my particular Lentek circuit board wasn't potted in and it should be easy to re-cap (thanks for the details). By the way Marco, is your LED green? Mine's red, but I'm not sure of the significance of this, or indeed, if there is one.
Rare Bird
21-11-2010, 17:54
Nick
I feel i've upset you, this wasnt intended.If so i Appologise.
What i do know is forums & i do not mix. Once again i appologise.
Hi Dave,
The LED on mine is also red, mate - and no, I don't see what significance that has either... :)
Like I said, I'd like to revisit a Koetsu (possibly a Red), as I suspect that on a much more neutral sounding T/T, like the Techie, the results could be rather good.
I'm also not sure if Sugano's son, who since the great man's death is now responsible for producing Koetsus, has quite the same skill as his father, and that's possibly one of the reasons why modern Koetsus sound somewhat different to those you heard in the 80s.
Fancy having a go at answering this I wrote earlier:
Considering that the design of all the above cartridges harks from a bygone era, where has modern cartridge design gone wrong, I wonder?
And, btw, I don't buy the notion that modern cartridges are simply more 'accurate', as that notion of accuracy simply doesn't match what I hear when I listen live to the sound of real acoustic instruments and the human voice.
I would describe the sound of a Decca, for example, as being 'musically accurate', but I bet it doesn't measure as well as its so-called more 'accurate' modern counterparts! ;)
We've definitely lost our way somewhere along the line with how much of the gear made today is voiced.
Marco.
I would choose the neatest if the wires were correctly routed & certainly wouldnt use tie wraps.
As mentioned above, if correctly exicuted there's no problems.
Neatness is neatness, rats nests are rats nests simples..
Nick
I feel i've upset you, this wasnt intended.If so i Appologise.
No upset no worries mate.
The problem with what you say is the "correctly executed" bit, within the high impedance inputs that abound inside a valve amp, running two conductors in parallel for a few inches can induce more cross talk than you might expect. I have seen several builds of amps that have been done with obsessive care that hum and are unusable until the loons are opened and signal wires removed and directly routed. Its not a excuse for just sloppy construction though.
Microscanner Decca's have a ruler flat response, but "only" 20db or so separation. The Microscanner also raises the tip resonance to over 20KHz and seems to control it better as well, compared with older "Decca" Decca's from the 80's.
The thing is, and I'll try to be careful how I word this, is that so many LP cuts were done with a boosted midrange/lower treble and just maybe, this is what many modern cartridges are reproducing - possibly. I can definitely say that all those old Decca SXL's were cut at half speed and most had oodles of eq done on them. When Decca got some shiny new Neumann VMS70(?) lathes which did a better job and at full speed too, the audio people didn't like it, despite the results being closer to what the producer originally wanted.
The thing is, many older cartridges have a bass-up/lower treble down kind of balance that possibly many vinyl cuts were tailored to, but I suspect it's the *quality* of whatever tonal balance that's the issue here, rather thanold the tonal balance itself.
You know Marco, the few very expensive "Top End" turntables I heard usually sounded dull, bland and lifeless, as though the sound had been through too many "refining-wringers." I remember a dire dem I had of the Rockport at £60K, the sound of the whole system (all Top End and expensive) being soporific in the extreme. This is where the dear old Rega 2/R200 really could run rings round many expensive concoctions, as it keeps the sound fresh and entertaining.
Anyway, that's all I can say.
Hi Nick,
have seen several builds of amps that have been done with obsessive care that hum and are unusable until the loons are opened and signal wires removed and directly routed.
Excuse my ignorance, but what are "loons"? :scratch:
Dave, good answer - I'll get to it tomorrow (just about to go off for an extended music sesh before bed).
Marco.
Ali Tait
21-11-2010, 21:53
It's a typo Marco, Nick means loom as in wiring loom.
Ah right - gotcha! I thought it was some fancy techie term only known by those 'in the know' :eyebrows:
Marco.
Stratmangler
21-11-2010, 22:03
Loons was a term used to describe unfeasibly wide flared trousers, once upon a while ago:)
Yep typo, sorry. Though I like the idea of calling out:
Release the loons....
I imagine them as a cross between a Werewolf a Borzoi and a Bandersnatch.
The Grand Wazoo
21-11-2010, 23:37
I prefer NOS Mullard Loons myself
Hi Dave,
Microscanner Decca's have a ruler flat response, but "only" 20db or so separation. The Microscanner also raises the tip resonance to over 20KHz and seems to control it better as well, compared with older "Decca" Decca's from the 80's.
Interesting... I'm pretty sure that, say, an OC-9 or Lyra Dorian (two modern MC cartridges I dislike with a passion) don't have a ruler flat response.
Indeed, I suspect that a graph of their frequency response would show a distinct treble lift on both cartridges, as that's certainly what one hears when listening to them, and it's this blatant 'treble lift' that annoys the shite out of me, as in a revealing, wide-open and neutral sounding system it's unpleasant and very obvious.
Whose idea was it, I wonder, to design this false 'excitement factor' into almost anything that is made in audio today, from cartridges to loudspeakers? Was it a conscious decision made collectively by all manufacturers based on an 'accepted standard', or what?
I'd love to know what it was that triggered this shift in how commercial equipment is voiced and when it happened.... Perhaps manufacturers now have over-compensated somewhat for the duller, warmer sound of *some* vintage gear? But this is the crux of the matter: how did they decide that this was the type of sound their customers wanted???
Or is it just natural evolution and the culmination of universally bad decisions being made by those with poor ears in positions of influence?
None of the vintage cartridges I own or have listened to recently, including the Decca and SPU, when set up and partnered properly, sound remotely dull, 'phat' or 'cuddly', but neither do they possess the obvious accentuation of the upper frequencies and spot-lit treble I hear in the vast majority of current MC (and MM) cartridges, regardless of price.
The fact is, I don't use the type of cartridges I do in order to obtain a euphonic, rose-tinted sound (far from it) - I do it to obtain a sonic presentation that to my ears resembles how real instruments and voices actually sound; i.e. a presentation that ultimately I consider as being more 'accurate' (as in "accurate" based on my experience of listening to the former, live and un-amplified).
What do the majority of today's cartridge manufacturers use as their benchmark in that respect, I wonder? ;)
The thing is, and I'll try to be careful how I word this, is that so many LP cuts were done with a boosted midrange/lower treble and just maybe, this is what many modern cartridges are reproducing - possibly.
Of course it's possible Dave, but I suspect that's not what is happening in most instances.
I don't doubt that, as you say, many LPs were cut that way. But as I've said before, the only way to accurately judge what a cartridge or T/T actually sounds like is to use the best recordings possible (read as most sonically neutral/'accurate') as the benchmark, and not the sonically 'tainted' examples you mention. Mo-Fi Original Masters, or other audiophile pressings of that ilk, are ideal for that purpose.
Because when you do so (and I've tried this many times), the sonic signature the cartridge imposes on the music becomes patently obvious. And in that respect, the thin-toned, treble accentuated, overtly cool and clinical sonic signature of most modern MM or MC cartridges is all too easy to hear.
Play the same recordings with, say, an SPU or a Decca, and what one hears isn't a cuddly or more 'romantic' rendition of the same recording (everything is still there, as it should be), but one simply devoid of the false treble emphasis superimposed onto the music by modern cartridges, as a result of how they've been voiced by the manufacturer, and so ultimately one is left with a more faithful reproduction of the recording, and thus of the music on it.
I can definitely say that all those old Decca SXL's were cut at half speed and most had oodles of eq done on them. When Decca got some shiny new Neumann VMS70(?) lathes which did a better job and at full speed too, the audio people didn't like it, despite the results being closer to what the producer originally wanted.
I don't doubt it. I'd have loved it though, as that's *precisely* what I strive for when listening to vinyl: to get as close to the original sound as possible, whether nasty or nice. That is after all what hi-fi is about!
The thing is, many older cartridges have a bass-up/lower treble down kind of balance that possibly many vinyl cuts were tailored to, but I suspect it's the *quality* of whatever tonal balance that's the issue here, rather thanold the tonal balance itself.
Again I fully agree, but I think where we differ, and please correct me if I'm wrong here, is that I choose cartridges that sound 'right' with neutral sounding, well-recorded pressings of my favourite music (as this is the only true benchmark for any notion of accuracy one can use), and if bad recordings of music I like sound crap as a result, then that's too bad, I'll just enjoy them for what they are (basically, I don't choose cartridges that merely flatter my record collection); whereas I feel you choose cartridges that make 'tainted' cuts of your favourite music sound better (i.e. you enjoy the sonic effect of the treble lift modern MC cartridges impose on these cuts), as perhaps those types of recordings are what make up the majority of your record collection?
After all, isn't that precisely what an LP12 did to many of the 70s and 80s recordings of the day - flatter them to the listener? There's nothing wrong with that, of course, as ultimately it's about enjoying your favourite music via whatever method is necessary. It's not quite how I do things, though.
Is that a fair analysis of the situation, or am I way off the mark and out of order? Just say! :)
You know Marco, the few very expensive "Top End" turntables I heard usually sounded dull, bland and lifeless, as though the sound had been through too many "refining-wringers." I remember a dire dem I had of the Rockport at £60K, the sound of the whole system (all Top End and expensive) being soporific in the extreme. This is where the dear old Rega 2/R200 really could run rings round many expensive concoctions, as it keeps the sound fresh and entertaining.
Lol - I know what you're getting at, and don't doubt what you heard for one second. But how did you arrive at the conclusion that it was the Rockport at fault?
I'm not a big fan of the vast majority of ultra hi-end equipment, as most of it in my experience flatters to deceive, where the biggest percentage of the design budget has been spent on aesthetic frippery, and what's 'under the hood' often rather neglected - or just as bad, full of 'boutique' components (to help justify the exorbitant asking price) that are often completely unnecessary, and which simply serve to complicate the signal path, making for that "dull, bland and lifeless" sound you refer to.
However, my suspicion wouldn't be for the Rockport as being the culprit, but rather the rest of the system, and perhaps the cables used, as in my experience most obscenely expensive cables strangle the life out of music (or highlight specific areas of the frequency range in order to give a superficially 'impressive' effect on the listener, a la Nordost).
Such cables have simply been designed as 'audiophile jewellery' in order to empty the wallets of the gullible that have more money than sense. Sadly, there are quite a few idiots out there for whom hi-fi is more about willy-waving and owning 'desirable badges', which they consider have 'prestige value', than enjoying their favourite music reproduced to the highest sonic standard :rolleyes:
T/Ts are a different ball game altogether, and it is here where standards of engineering ultimately govern what is possible from vinyl reproduction, and one usually has to pay for the privilege of owning the finest examples of such.
Therefore in that respect, I'd bet that if a genuinely top-notch musical sounding system (based on your standards and mine) were assembled and fronted by both the P2 and the Rockport, using the same arm and cartridge, the P2 would (quite naturally) be shown up as decent but grossly inferior.
We must try it some time! ;)
Marco.
Loons was a term used to describe unfeasibly wide flared trousers, once upon a while ago:)
At the risk of being a pedantic 70s fashion victim...what you are describing there are 'dusters' or 'Oxford Bags', very popular with the budding football hoolies of the early 70s, the 'loon' was a slightly different beast favoured by hippies in the late 60s, lower cut and flared at the bottom, often seen in velvet and covered in embroidery...
...I'll get my loons
Hi Dave,
Interesting... I'm pretty sure that, say, an OC-9 or Lyra Dorian (two modern MC cartridges I dislike with a passion) don't have a ruler flat response.
Indeed, I suspect that a graph of their frequency response would show a distinct treble lift on both cartridges, as that's certainly what one hears when listening to them, and it's this blatant 'treble lift' that annoys the shite out of me, as in a revealing, wide-open and neutral sounding system it's unpleasant and very obvious.
Whose idea was it, I wonder, to design-in this false 'excitement factor' into almost anything that is made in audio today, from cartridges to loudspeakers? Was it a conscious decision made collectively by all manufacturers based on an 'accepted standard', or what?
I'd love to know what it was that triggered this shift in how commercial equipment is voiced and when it happened.... Perhaps manufacturers now have over-compensated somewhat for the duller, warmer sound of *some* vintage gear? But this is the crux of the matter: how did they decide that this was the type of sound their customers wanted???
Or is it just natural evolution and the culmination of universally bad decisions being made by those with poor ears in positions of influence?
None of the vintage cartridges I own or have listened to recently, including the Decca and SPU, when set up and partnered properly, sound remotely dull, 'phat' or 'cuddly', but neither do they possess the obvious accentuation of the upper frequencies and spot-lit treble I hear in the vast majority of current MC (and MM) cartridges, regardless of price.
The fact is, I don't use the type of cartridges I do in order to obtain a euphonic, rose-tinted sound (far from it) - I do it to obtain a sonic presentation that to my ears resembles how real instruments and voices actually sound; i.e. a presentation that ultimately I consider as being more 'accurate' (as in "accurate" based on my experience of listening to the former, live and un-amplified).
What do the majority of today's cartridge manufacturers use as their benchmark in that respect, I wonder? ;)
Of course it's possible Dave, but I suspect that's not what is happening in most instances.
I don't doubt that, as you say, many LPs were cut that way. But as I've said before, the only way to accurately judge what a cartridge or T/T actually sounds like is to use the best recordings possible (read as most sonically neutral/'accurate') as the benchmark, and not the sonically 'tainted' cuts you mention. Mo-Fi Original Masters, or other audiophile pressings of that ilk, are ideal for that purpose.
Because when you do so (and I've tried this many times), the sonic signature the cartridge imposes on the music becomes patently obvious. And in that respect, the thin-toned, treble accentuated, overtly cool and clinical sonic signature of most modern MM or MC cartridges is all too easy to hear.
Play the same recordings with, say, an SPU or a Decca, and what one hears isn't a cuddly or more 'romantic' rendition of the same recording (everything is still there, as it should be), but one simply devoid of the false treble emphasis superimposed onto the music by modern cartridges, as a result of how they've been voiced by the manufacturer, and so ultimately one is left with a more faithful reproduction of the recording, and thus of the music on it.
I don't doubt it. I'd have loved it though, as that's *precisely* what I strive for when listening to vinyl: to get as close to the original sound as possible, whether nasty or nice. That is after all what hi-fi is about!
Again I fully agree, but I think where we differ, and please correct me if I'm wrong here, is that I choose cartridges that sound 'right' with neutral sounding, well-recorded pressings of my favourite music (as this is the only true benchmark for any notion of accuracy one can use), and if bad recordings of music I like sound crap as a result, then that's too bad, I'll just enjoy them for what they are (basically, I don't choose cartridges that simply flatter my record collection); whereas I feel you choose cartridges that make 'tainted' cuts of your favourite music sound better (i.e. you enjoy the sonic effect of the treble lift modern MC cartridges impose on these cuts), as perhaps those types of recordings are what make up the majority of your record collection?
After all, isn't that precisely what an LP12 did to many of the 70s and 80s recordings of the day - flatter them to the listener? There's nothing wrong with that, of course, as ultimately it's about enjoying your favourite music via whatever method is necessary. It's not quite how I do things, though.
Is that a fair analysis of the situation, or am I way off the mark and out of order? Just say! :)
Lol - I know what you're getting at, and don't doubt what you heard for one second. But how did you arrive at the conclusion that it was the turntable to blame?
I'm not a big fan of the vast majority of ultra hi-end equipment, as most of it in my experience flatters to deceive, where the biggest percentage of the design budget has been spent on aesthetic frippery, and what's 'under the hood', often rather neglected - or just as bad, full of 'boutique' components (to help justify the exorbitant asking price) that are often completely unnecessary, and that simply serve to complicate the signal path, making for that "dull, bland and lifeless" sound you refer to.
However, my suspicion wouldn't be for the Rockport as being the culprit, but rather the rest of the system, and perhaps the cables used, as in my experience most obscenely expensive cables strangle the life out of music (or highlight specific areas of the frequency range in order to give a superficially 'impressive' effect on the listener, a la Nordost).
Such cables have simply been designed as 'audiophile jewellery' in order to empty the wallets of the gullible that have more money than sense. Sadly, there are quite a few idiots out there for whom hi-fi is more about willy-waving and owning 'desirable badges', which they consider have 'prestige value', than enjoying their favourite music to the highest standards of reproduction :rolleyes:
T/Ts are a different ball game altogether, and it is here where standards of engineering ultimately govern what is possible from vinyl reproduction, and one usually has to pay for the privilege of owning the finest examples of such.
Therefore in that respect, I'd bet that if a genuinely top-notch musical sounding system (based on your standards and mine) were assembled and fronted by both the P2 and the Rockport, using the same arm and cartridge, the P2 would (quite naturally) be shown up as decent but grossly inferior.
We must try it some time! ;)
Marco.
PLANAR 2/R200 Marco, not the replacements :lol:
I'm sure you're right. It's been too long and I only have old memories now. That Rockport system was what I've heard a few times from so called "Top End" systems of the period. Obviously, I wasn't able to listen to the Rockport in a more familiar system, but I do remember bits of these type of systems coming our way over the years and each part in isolation tended to sap the life out of the music. Add the whole lot up and you can guess my "conclusion." The thing is, I wonder if a "well finished cutting lathe" of a deck like the Rockport really would sound any better than a properly terminated Techie with a vinyl/platter matching mat? Maybe the bass might be better but it would be fascinating to compare (fat chance though).
I'd love to try a modern SPU at home again one day, but I need a suitable turntable first. The TD125 is good for 1.5g trackers, but anything heavier would induce dynamic wow I think and the R200 (bless it) isn't really suitable either. A decent high-torque direct drive makes perfect sense in this case. Thing is, I like a lively sound from vinyl, but do agree that many midrange MC's can "etch" the sound too much - this is where the AT33EV may just mellow things a tad, as the elliptical tip shouldn't be as fussy as the ML type in the OC9 and PTG. Conversely, the fancy profile on a SPU or two may just liven things up a bit and restore the balance over the older ones I heard.
I just wish to repeat again and you lot are welcome to pick me up on it - anything I say on these forums is from experience and possibly "fact" as I see it at the time. HOWEVER, I do try hard not to be blinkered and am always open to be proved wrong, with gushing apologies as necessary. I very much appreciate the positive aspects of the "training" I had from Linn in the early days, but also realise how limiting that darned turntable was, both in its abilities pre Cirkus and also in the blinkered attitude I and many others had towards other decks at the time. You can thank my mastering engineer friend, my Revox B77 and hifi Dave for opening my eyes....
PLANAR 2/R200 Marco, not the replacements :lol:
Lol - one 'Toytown turntable' to me is the same as any other. Only kidding! ;)
Regas have their place and aren't bad little T/Ts. I'm glad you weren't offended by my remarks about cartridges, as it's simply how I see it.
I agree with what you've written, particularly this bit:
I just wish to repeat again and you lot are welcome to pick me up on it - anything I say on these forums is from experience and possibly "fact" as I see it at the time. HOWEVER, I do try hard not to be blinkered and am always open to be proved wrong, with gushing apologies as necessary. I very much appreciate the positive aspects of the "training" I had from Linn in the early days, but also realise how limiting that darned turntable was, both in its abilities pre Cirkus and also in the blinkered attitude I and many others had towards other decks at the time. You can thank my mastering engineer friend, my Revox B77 and hifi Dave for opening my eyes....
I'm very glad that Linn chip so firmly embedded in your bonce has now duly been dissolved! Fancy spreading the cure?? There are sadly still many lost souls inflicted by Linnomania and flatearthism, although happily not on here.
We're all here to learn from each other's experiences on AoS. The good thing is that the knowledge and experience of many of our contributors is exceptional and there are no bullshitters with petty agendas to exploit who simply enjoy scoring points and ramming home their supposed 'intellectual superiority' at any given opportunity, as happens so often elsewhere in forum-land... :rolleyes:
Now, get that bloody Lentek of yours modified the same as mine, as you'll be amazed at just how good it can sound! :cool:
Marco.
Cool, glad it works.
The bits I used were:
From www.rapidonline.com
47uF 6.3V OSCON SA Electrolytic Capacitor 4 off Part # 11-2508
47u 10V OSCON SC Electrolytic Capacitors 2 off Part # 11-2522
From www.rswww.co.uk
Radial polyprop cap,2.2nF 100V 2.5mm 2 off Part # 247-0271
Radial polyprop cap,10nF 100V 2.5mm 3 off Part # 247-0300
I don't have enough left to make up a set of all the bits, but if you can't get any of them, let me know and I will add them to the next order I send to them both for you.
The connectors used were from HiFi Collective
CMC gold plated RCA sockets one pair
CMC-1036-WF RCA plug one pair
AT LAST - I've got my brain in gear and ordered some bits to complete the job!!! What's broght this to a head has been the excellent sonics of the Stilton OC9 in the second SL1500 I've had in a year. The rather dark tones of this model being amply balanced by the light-n-bright OC9.
All great fun and I'll try my best to do a neat job and keep the bits I remove, just in case :lolsign:
Excellent stuff, Dave. I'm looking forward to reading your findings - certainly the improvement in my unit was quite substantial :)
Marco.
Rare Bird
13-03-2011, 13:21
don't forget pickies for mr perfect to look at :eyebrows:
Ok, but I only have 6.3Mp to use - not hi-res enough for the anti-digital types around and about :ner:
I do like the Shark wires though (their silver plated cable made excellent interconnects without sounding "silvery" to me, but that's another story).
thats a very interesting comment .....and at total variance to my experience ...which suggests a couple of things ...you've tried some new shark cable ..that I have not or
you have not heard good silver cable ....
all the shark cables are coaxial ... and tend to sound the same ...infact all coaxials tend to sound similar ....which is why many people can't hear any differences between cables imo
a few observations on cables ....compared to a simple silver twisted pair ...no shielding
copper tends to sound big warm round ...tends to have a hump in the upper bass often enough to blot out the low bass ....especial common on multi strand cables. or I could say limited in solid single core cables.
silver plated copper similar to above but add in a bright metalic top end...imo the worst of both worlds
if this is sounding good then its possible you have issues elsewhere!
silver [thats at least 4n] should sound smooth buttery neutral and natural ....with dynamics to die for .
if your not hearing this ..and you have silver cable ...then its either not silver or theres a lot of stuff mixed in with it like copper or iron ...or even the ground side is copper.
silver gold [not gold plated] rich warm fast dynamic deeper bass than silver on its own.
gold rich warm deep bass
silver gold plated ...again worst of both worlds theres a patern developing here !
platinum ....makes everything else sound metalic and unmusical ....but totally unafordable [ie cost price of plus £1k for 0.5m pair]
And yes I've made most configurations of these ...
if you can live with a simple twisted pair of any metal thats a single solid core ...your going to have a cable thats going to be hard to beat ...
though you will probabley need shielded cables to run from tone arm to head amp as the signals are so small ..
back to thread subject .....
why not try stargets ...I've found these much more musical than oscons .....I limit oscon to power supplie duties which there very goood at ..black gates are ok if you can everget them burned in [if thats the right term] ...once left off I've found they revert back .....so though stargets aren't as good ....they sound pretty good straight out the box and require little running in therefore on the whole they may sound better than none run in blackgates .
did you consider silver mica for the ceramics ?
wimas are pretty decent though .
and finally .....rca plugs with low metal mass will sound better than big chunky ones ...even expensive ones ...
Hmmm....I have one of these lurking in my parts bin....maybe I'll give it ago.
The silver-plated Shark cable is too big to fit into the Lentek sadly. I'll stay with the Neutrik plugged original wires for now I think..
Well, I've been running this thing rebuilt all evening into the "office" lo-fi setup and frankly, I'm stunned. The system up here doesn't "do" fine details, so only the obvious bits are reproduced. The Shadows first album (1980 stereo version) has air and space that isn't quite as clear using the AVI on its MC setting. Less bass though, but that doesn't bother me, as the "quality" of the bass seems superior.
Setup used - Technics SL1500/ADC shell with Sumiko wires/Stilton OC9 into the Lentek/AVI S2000MP+P/Belkin Silver Audio series IC's to M-Audio 24/96/Labtec Spin 70 powered speakers.
The really telling thing though is the improved diction of John Martyn's slurring singing style on side 2 of his "One World" album. The famous "Small Hours" track is just sublime.
Thanks again Marco :) - and Nick for sharing the upgrade details with us. Pics tomorrow..
Nice one, dude - glad it worked out well! Nick's the talented one, though, not me. Look forward to reading more :)
Marco.
Apologies to Nick if I appeared to leave him out. Without his help I wouldn't have known what components to purchase - I am grateful Nick - honestly :)
A few pics - first the board before -
http://i132.photobucket.com/albums/q8/DSJR_photos/DSCF1456.jpg
And now, with eleven caps replaced -
http://i132.photobucket.com/albums/q8/DSJR_photos/dd723156.jpg
http://i132.photobucket.com/albums/q8/DSJR_photos/a90c20e6.jpg
Sonically, I can confirm the "grain" has gone, but doubts currently remain concerning the perceived bass weight. Now, this could be because of the Stilton OC9 not having much to start with ;) and I can see how the modded Lentek would be perfect with a Denon 103 (would the SPU push it too hard?).
I haven't changed the existing external wires, as the cable seems to be a good quality screened cable with still clean copper, but as the suspect plugs weren't there to start with on mine, I'd already fitted a pair of Neutrik pro plugs....
Next project - to upgrade the bits on my 1.1M J-FET line buffer and compare it to the modded X10-D...
Definitely no problem here whatsoever with lack of bass weight with either a DL-103 or EMT TSD-15 (using an adapter for the Jelco), both of which I've used with great success with the modded Lentek :)
The OC9, as you intimate, won't be the best match, so if you *really* want to hear what the Lentek is capable of, you need to obtain a DL-103, where you will discover a match truly made in heaven.....
The SPU is a no-go, quite simply because it hates the 100 Ohms loading (needing instead something around 10-20 Ohms), and as a result sounds distinctly bass-light and 'tinselly'.
One thing I've found with the Lentek is that it'll only perform at its absolute best when the battery is at its newest - and I mean newest. A few days solid use is therefore liable to reduce battery life quite considerably, even if the battery testing light is still illuminated quite brightly.
This means nada, and its sonic performance is liable to be some way off from what it was when the battery was new, with the sound being rather soft and lacking in impact in comparison. Therefore, if the Lentek is in daily use in your system, and you listen to vinyl for many hours a day, prepare to factor in the cost of between two to three batteries a month (and for best performance, they must be Duracells) to ensure that sound quality remains optimised.
Obviously this is costly, and so that's the downside. Fortunately, the Lentek/103 isn't my regular combo, so I don't go through batteries too often.
The design could really do with being powered by two 9V batteries, not just one, or via some form of external main-powered PSU. Perhaps this is something which our resident DIY-ers could look at?
Marco.
why not try stargets ...I've found these much more musical than oscons .....I limit oscon to power supplie duties which there very goood at ..black gates are ok if you can everget them burned in [if thats the right term] ...once left off I've found they revert back .....so though stargets aren't as good ....they sound pretty good straight out the box and require little running in therefore on the whole they may sound better than none run in blackgates .
Yep, all sorts of things could be used, but you need to consider the available space (or lack of it).
Apologies to Nick if I appeared to leave him out
I never noticed any sign of you doing that, no worries.
That means nada, and sound quality is liable to be some way off from what it was when the battery was new, sounding rather soft and lacking in impact in comparison. Therefore, if the Lentek is in daily use in your system, and you listen to vinyl for many hours a day, prepare to factor in the cost of two or three batteries a month to ensure that performance remains optimised.
Or use rechargables and leave them on charge when not in use.
Yes, Nick, that would probably work. Would it be possible though to design an external mains-powered PSU? :)
Marco.
Yes, it would,but you will need to ensure very quiet DC. could be done though. The circuit board could be removed and the whole thing put in its own case. Probbaly best to power with a wall wart type DC supply and then filter then DC from that point to be as quiet as needed.
Its a bit more than a simple supply though, it needs to float.
I think I will have a search round B&Q and look at their solar power garden lights. A good solution to make a floating supply would be 9v worth of solar cells and a bunch of LED's illuminating them.
Remember my aborted efforts with a large 12V (actually 15V) transformer and a regulated supply board? HUMMMMMMMMMMMMMM
I'm sure you're correct about battery Marco and a decent external supply may not be economical. it's probably better for Nick and others to design another circuit or use a similar one that isn't so fussy, or dedicated to a battery supply in the first place.
By the way Marco, that darned LED illuminates with less than 6V input.......
Piccies have vanished Marco.
Yeah, just noticed. I will look into that :)
In the meantime, the ones on Dave's post #80 should suffice: http://theartofsound.net/forum/showthread.php?8431-Nick-G-modified-Lentek-Head-Amp&p=197973#post197973
Marco.
Just wondering if a 12v SLA Yuasa security alarm battery would be a possible alternative? Would the extra voltage create problems?
Marco's observations about the fresh battery sounding superior are spot on. I use a similar phono head amp from Rogers. I replaced the battery yesterday, the new replacement measured 9.7v, the old one 9.0v. I would love to try one of my 12v Yuasa's but worried I might cause damage.
awkwardbydesign
05-08-2014, 07:59
I just read this- http://taperssection.com/index.php?topic=157574.0
Re: A 9V Battery is NOT!
« Reply #6 on: August 14, 2012, 01:54:54 PM »
FWIW the Powerex rechargable 9V batteries have a nominal voltage of 9.6 but when new, fully charged and without load are between 10.5 and 11.5V. The Nbox doesn't seem to work well with the rechargable 8.4V but does great with alkaline or these Powerex ones. So if anyone needs a batter in the shape of a 9V and needs more than 8.4, it might be worth trying the Powerex.
EDIT: Branding is Powerex, not sure why I was thinking Maha.
EDIT: I just checked again and they are Maha Powerex. I give up. :P
« Last Edit: August 14, 2012, 01:58:03 PM by johnw »
There's no doubt that any battery powered audio device is only going to perform at its full sonic potential when the battery powering it is operating at maximum capacity - and as has been mentioned, listening tests have confirmed this.
It's one of the reasons why, despite the obvious advantages with no mains in the equation, I've never gone the battery operated phono stage route, quite simply because I'd always be aware of the degradation in sound quality, as the battery slowly loses power - and that's just too much of a 'head fuck'... :nono:
However, despite that, considering the small outlay involved, I'd URGE any DL-103 owner, looking to maximise its sonic potential, to try using it with a Lentek MC head amp (particularly a judiciously modified one), and especially if they have a valve MM phono stage, as the results obtained are sublime and indeed superior to those I've achieved to date with any standalone active solid-state phono stage! :)
Marco.
Smegger68
11-02-2015, 18:12
This is highly interesting... I have one of these Lentek amps and I am rather partial to the sound it produces. Will have to look into this in detail!
Go for it, James, as I assure you it's worth it!
Lenteks and Crofts are a marriage made in heaven anyway, but a judiciously modified Lentek is even better... Next time I'm down your way, visiting a friend in Ystrad Mynach, I'll pop by and bring my Lentek with me, and we'll try it in your system :cool:
Marco.
jollyfix
11-02-2015, 19:19
Next time your down Ystrad ( i assume to see Anthony), give us a shout, i visit Ystrad regulary .
No worries, Dave - will do... And yes, it'll be to visit Anthony :)
Marco.
The Barbarian
11-02-2015, 20:27
The A&R 'HA10' was a good un anorl..Used mine in the late 80's for a month or so, never seen the light of day since
http://www.audiosmile.com/forum/Manual/HA10%20CART%20PREAMP.pdf
Smegger68
22-02-2015, 01:13
If you're talking about a certain Anthony who builds some lovely valve amps then I am acquainted with the gentleman. He did some repair work on my Audion a couple of years back. You'd be more than welcome to teas and biscuits while we listen to that Lentek :)
Hi James,
Yup, the same Anthony! Okies, next time I’m due down at his place I’ll give you a shout :)
Marco.
jandl100
22-02-2015, 15:00
The A&R 'HA10' was a good un anorl..Used mine in the late 80's for a month or so, never seen the light of day since
http://www.audiosmile.com/forum/Manual/HA10%20CART%20PREAMP.pdf
Yep, I love mine, Andre - bought it from a Wammer a couple years ago and was amazed how good it is.
I'm buying a standard Lentek mc stepup - I'll be putting it up against the A&R HA10. :)
The Barbarian
22-02-2015, 15:30
Yep, I love mine, Andre - bought it from a Wammer a couple years ago and was amazed how good it is.
I'm buying a standard Lentek mc stepup - I'll be putting it up against the A&R HA10. :)
Rogers made one at this time aswell, around the same price..
audioholic
26-02-2015, 11:28
Hi guys,
just noticed this thread I've had a lentek head amp from back in the day.
Although subsequently have gone the decca route as the costs and madness of moving coil amps and step ups etc seemed just too silly.
But my little problem is that my duracell seems to be really hard to disengage from that connecting tab. Any tips..
Ali Tait
26-02-2015, 12:01
Lever off with a screwdriver?
Ali Tait
26-02-2015, 12:02
Make sure you don't short out the terminals though!
audioholic
26-02-2015, 14:11
Yeah I know the screwdriver levering thing was my first thought,just felt a bit brutal.
Yeah I know the screwdriver levering thing was my first thought,just felt a bit brutal.
The 'snap-fastner' type battery connections can be quite tight. If you don't like the thought of using a screwdriver, then you could try a flat lolly stick, held close to the connectors to prise it off.
Smegger68
27-02-2015, 14:52
The connector in mine is broken in two, obviously from some serious force being applied in the past. Might be an idea to get a replacement part soldered in at some point, but I do quite like the idea of a nice quiet 9v supply instead...
337alant
27-04-2015, 20:23
Interesting thread :)
Hadn't thought you could get all that gunk from around the components without damaging something
Might give this ago with my little Lentek when I get time
I used to use mine with a simple 3 opp amp diy MM stage and it sounded great to me ;)
It wiped the floor with the Cambridge phono on the right
https://farm9.staticflickr.com/8260/8654913734_42d5b1b016_c.jpg (https://flic.kr/p/ebNGjA)004 (https://flic.kr/p/ebNGjA) by 337alant (https://www.flickr.com/people/69508926@N05/), on Flickr
https://farm9.staticflickr.com/8250/8662772119_115f053802_c.jpg (https://flic.kr/p/ecuYkZ)118 (https://flic.kr/p/ecuYkZ) by 337alant (https://www.flickr.com/people/69508926@N05/), on Flickr
Alan
Wakefield Turntables
27-02-2016, 20:13
Thanks for the link Marco, I'll have to take mine apart and see what Nick has done to it. It would be interesting to see if he's stuck to tried and tested methods. First impressions are very promising.
tubehunter
03-03-2016, 15:25
Sorry about the focus, taken with my iPhone.
http://i514.photobucket.com/albums/t350/halx00/4D5F2B2A-32D3-48B1-8E4E-3DC36B30B85D_zpsenqcyhws.jpg (http://s514.photobucket.com/user/halx00/media/4D5F2B2A-32D3-48B1-8E4E-3DC36B30B85D_zpsenqcyhws.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/5F8A5021-543B-4A45-B5FA-E5FA103CBFA8_zpsfwfdxtzx.jpg (http://s514.photobucket.com/user/halx00/media/5F8A5021-543B-4A45-B5FA-E5FA103CBFA8_zpsfwfdxtzx.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/9C7D6B6D-F4A3-4F61-8141-C3401C2BF2F8_zpsczyoo0my.jpg (http://s514.photobucket.com/user/halx00/media/9C7D6B6D-F4A3-4F61-8141-C3401C2BF2F8_zpsczyoo0my.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/BB653CEF-B42E-4EA9-9A27-48370DBBE3D3_zpsamcbkde2.jpg (http://s514.photobucket.com/user/halx00/media/BB653CEF-B42E-4EA9-9A27-48370DBBE3D3_zpsamcbkde2.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/AE1D93ED-E9B3-4245-88D5-C20C1DA956E3_zpsiggfy7ne.jpg (http://s514.photobucket.com/user/halx00/media/AE1D93ED-E9B3-4245-88D5-C20C1DA956E3_zpsiggfy7ne.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/CA59287E-DFB9-4EC9-9FE2-66E547CD49F4_zpslfgmrxuh.jpg (http://s514.photobucket.com/user/halx00/media/CA59287E-DFB9-4EC9-9FE2-66E547CD49F4_zpslfgmrxuh.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/EE86B2D7-4BB9-4191-ACB2-E68055EF27F3_zps8qfeau1d.jpg (http://s514.photobucket.com/user/halx00/media/EE86B2D7-4BB9-4191-ACB2-E68055EF27F3_zps8qfeau1d.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/2563E9CD-A9CA-4FCA-AB5C-423C37BBFA81_zps2opusya7.jpg (http://s514.photobucket.com/user/halx00/media/2563E9CD-A9CA-4FCA-AB5C-423C37BBFA81_zps2opusya7.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/0F51486F-758E-4B82-82FB-EBBD12153278_zpsf8aizu8r.jpg (http://s514.photobucket.com/user/halx00/media/0F51486F-758E-4B82-82FB-EBBD12153278_zpsf8aizu8r.jpg.html)
Wakefield Turntables
03-03-2016, 15:39
Very nice Duncan I'll see what I can do later tonight.
Lol... I think some context is needed here. The pics above are of my stock Lentek, which Duncan had to dig out (as it was potted), in order to change the output cables and phono sockets. Those are the 'before' pics. The last two are 'afters', but it doesn't show you much, in terms of the cables and phono plugs used.
There will be some component changes later, but for now, some Eichmann solid-copper RCA sockets have been fitted, along with Cardas output cables, which themselves have been fitted with solid-silver KLE Harmony plugs. Needless to say, it sounds superb, and a big improvement on what was fitted before!
Cheers, Dunc :cool:
Marco.
P.S Oh, and one other thing... This Lentek is rather different internally from ones I've had before, as it has different transistors. Perhaps an earlier or later model?
Wakefield Turntables
03-03-2016, 19:45
Well i tried getting into mine and Nick's done a bloody good job of making sure no-one can get in and a sneaky peak. It has been modded and from what I can see he's done the following
1. Upgrade the caps
2. Upgraded cabling to WBT
3. Internally its all silver wire (I think)
4. Silver plated female RCA's
Not sure if he's done anything to the resistors.
Not intentionally, I just put it back as it was, the PCB in a plastic potting case. I replaced the tants for elna slmic II I think and the ceramic cap for a film one. I left the resistors alone as the carbon comps are not bad sounding. CMC RCA's and wiring supplied by the owner.
337alant
15-09-2016, 19:29
Cool, glad it works.
The bits I used were:
From www.rapidonline.com
47uF 6.3V OSCON SA Electrolytic Capacitor 4 off Part # 11-2508
47u 10V OSCON SC Electrolytic Capacitors 2 off Part # 11-2522
From www.rswww.co.uk
Radial polyprop cap,2.2nF 100V 2.5mm 2 off Part # 247-0271
Radial polyprop cap,10nF 100V 2.5mm 3 off Part # 247-0300
I don't have enough left to make up a set of all the bits, but if you can't get any of them, let me know and I will add them to the next order I send to them both for you.
The connectors used were from HiFi Collective
CMC gold plated RCA sockets one pair
CMC-1036-WF RCA plug one pair
Nick can I request a clarification
2 of the ceramics I removed measured 220pf, the other 3 measured 10nf
in your list you have 2.2nf & 10Nf
Alan
Hi Alan,
For a quicker answer, I'd PM Nick, as I believe he's currently taking a break from posting on the open forum, or if you get no joy there I'll give you his email address :)
Marco.
337alant
16-09-2016, 21:23
Thanks Marco and yes Nick made contact with me offline :)
Alan
337alant
22-09-2016, 21:54
Steve gave me his Lentek Head amp as it was very noisey and making a quacking noise
I also have one of these lentek MC step up amps which I used for a few years and know it well, so after looking up this tread I tought I would experiment with my unit with components that I had in the parts draws.
All I did was changed all the caps with 47uf & 10uf Nichicon KZ Muze and 22pf & 10nf Evox PFR poly prop film caps
I left all resisters and transisteors in pleece as they all measured OK
The blue tants I removed were all bad so need ed replacing
As Nick stated the PCB is potted so you have to puck all of the compound out bit by bit to reveale all the components
The bakerlite case also fell to pieces on mine so I remounted the PCB on a 0.5 sheet of PTFE and double sided foam tape.
Its a fidly job as there is not much space in this small case
I also replaced the leads with some Klotz MC500 and shark phono plugs
Resuts is a very nice sounding head amp which as stated perviously takes off the hard edge of the original tants.
I will do the same on Steves unit when I get some more parts
And maybe I will revisit mine and change all the resisters with Dale RN55d and see if there are some quieter alternatives for the BD380 transisters.
Note this will not be replaceing my Paradise phono however :eyebrows:
Some pics
https://c5.staticflickr.com/9/8178/29827192836_9d2c240e0e_c.jpg (https://flic.kr/p/MrJags)IMG_2681 (https://flic.kr/p/MrJags) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
https://c7.staticflickr.com/9/8415/29827191326_37578025be_c.jpg (https://flic.kr/p/MrJ9Pq)IMG_2682 (https://flic.kr/p/MrJ9Pq) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
https://c7.staticflickr.com/6/5705/29826793406_3868ba2754_c.jpg (https://flic.kr/p/MrG7wJ)20160922_224227[1] (https://flic.kr/p/MrG7wJ) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
https://c1.staticflickr.com/6/5314/29568613160_b5c9c457fc_c.jpg (https://flic.kr/p/M3SSxb)IMG_2765 (https://flic.kr/p/M3SSxb) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
Wakefield Turntables
23-09-2016, 09:45
Great post Alan. I could take mine apart and photograph it if you wish so you can see how mine's been modded. I agree with you that the Lentek won't be replacing the Paradise.
337alant
29-11-2016, 01:23
I finally got round to repairing Steves (Floydroids) Lentek as it had a rustling and occasional quac from the right channel
I tracked it down to a 15k resister that had no steady measurement is just kept climbing as you measured it ? also 2 x tantalum caps duff on the right channel so I replaced all resisters for metal film with the 100 ohm loading resisters for Dale RN60.
All tantalums changed for Elna Silmic 2 and all small value for polyprops all values were measured and matched.
The output transistors were also changed for matched pair of BD438.
Ouput cables Klotz MC5000 and Shark Phono plugs
It sounds great to me :eyebrows::D
https://c5.staticflickr.com/6/5681/30484942684_316930e4de_c.jpg (https://flic.kr/p/NrRio5)20161127_190556 (https://flic.kr/p/NrRio5) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
Firebottle
29-11-2016, 05:17
Good job Alan :thumbsup:
DarrenHW
29-11-2016, 08:57
Good job Alan :thumbsup:
+1, are the new transistors much quieter?
Excellent work as usual, Alan! :thumbsup:
For me, the little Lentek head amp is a revelation and somewhat of a design classic. I've no idea why it sounds as good as it does [perhaps the sheer simplicity of the circuit and/or the design of the circuit itself, after all, some 'recipes' just work], in reality it has no right to sound so good, but I first used one of these devices in 1982, with my (then) Ariston RD11S/Linn LVV/Denon DL-103 combo, through a Sondex S230 integrated amp, which incidentally had a superb MM phono stage on board, and even then I couldn't believe how good the sound I was getting from vinyl replay.
Fast forward to 2016, at this year's MiBO show, and the little Lentek I brought with me, which incidentally was stock, apart from fitting some solid-copper Eichmann phono sockets, Cardas 21-AWG pure-copper litz shielded interconnect wire, complete with WBT 0102Ag RCAs, sounded just as impressive in a modern context, in conjunction with and also up against some very good equipment indeed, as I'm sure Alan (Firebottle) would attest to... ;)
Even at home, it gives my £1500 Paul Hynes head amp/PSU a run for its money, which is just ridiculous, but the Lentek (especially in conjunction with a DL-103) imbues music with an infectious joie de vivre, PRaT [pace, rhythm and timing], which would give any Naimee a hard-on. It sounds 'punchy' and dynamic, simultaneously making other head amps and SUTs sound somewhat soft and limp, but once subtly fettled (with judicious replacement/upgrading of caps, resistors, etc) never strays into aggressiveness.
On that note, I would exercise caution, as the temptation is simply to rip out components that superficially seem 'wrong' or 'inferior', but are actually key to producing the effusive, fun-filled sound the Lentek is renowned for, and as such you can end up sucking the life out of it, filling it with so-called 'superior' audiophile components. Yes, those may be electrically superior, but sonically, not as well-suited to maintaining the optimal 'sonic recipe', and so you end up with a sound that's a bit too smooth and 'controlled'.
That's precisely why, with the current Lentek I've got, I've so far kept it simple and replaced the 'no-brainer' inferior items from the 70s/80s, such as the horrible (in comparison with what's available today) original phono sockets, signal output leads and RCA plugs. Honestly, the difference that made alone was rather surprising! :eek: And furthermore, it allowed me to hear what the circuit was doing 'as is', highlighting that there's not a lot wrong with it, but that it would benefit sonically from some light tweaking and the addition of a soupçon more subtlety and refinement.
However, the tricky bit now will be ascertaining which components are best changed/upgraded, in order to achieve that effect, but crucially without robbing the unit of its 'fun factor'! I think I'll start with the resistors and work forward from there to caps and transistors, so watch this space soon for various in-depth comparisons of such, before I end up with what I consider as optimal, and 'voice' the Lentek to my tastes accordingly! :cool:
Marco.
Firebottle
29-11-2016, 10:55
..... sounded just as impressive in a modern context, in conjunction with and also up against some very good equipment indeed, as I'm sure Alan (Firebottle) would attest to... ;)
:exactly: I'd not actually heard a Lentek before but have played with a transistorised head amp of similar vintage (the one I lent to Jimbo as a head amp starter).
I was impressed and as Marco suggests I think it is down to the simplicity of the unit. Replacing the capacitors for better lower loss versions is almost De Rigeur, but I would advise not to replace the transistors (unless your unit is particularly noisy) as the type was chosen for good reason.
They have a larger semiconductor 'chip' inside compared to the more traditional small signal transistor, being chosen for low noise performance.
:)
337alant
29-11-2016, 23:59
Darren
No not much difference in the noise but at least these are matched as the ones I remove had a HFE of 50 and 105 so poor current gain matching
Generally though the Lentek does sound less noisy than the original
Alan
RothwellAudio
30-11-2016, 11:55
Sorry if I've missed it, but is there a circuit diagram for this headamp somewhere? That has to be the place to start if anyone is thinking of changing anything.
Floyddroid
05-12-2016, 10:25
I finally got round to connecting the Lentek to my Firebottle having reconfigured it back to MM. Straight away i noticed a much more lively and informative sound using my Denon 103. Transiants and attack where much tighter as if a spanner had been taken to the sound. Vocals didn't seem to have the depth as with the Firebottle on it's own but this was more than made up for by the overall musicality. Drum kit really did sound like a drum kit and guitars both acoustic and electris seemed to have more sparkle. Many thanks Alan, you are a gifted chap.
I finally got round to repairing Steves (Floydroids) Lentek as it had a rustling and occasional quac from the right channel
I tracked it down to a 15k resister that had no steady measurement is just kept climbing as you measured it ? also 2 x tantalum caps duff on the right channel so I replaced all resisters for metal film with the 100 ohm loading resisters for Dale RN60.
All tantalums changed for Elna Silmic 2 and all small value for polyprops all values were measured and matched.
The output transistors were also changed for matched pair of BD438.
Ouput cables Klotz MC5000 and Shark Phono plugs
It sounds great to me :eyebrows::D
https://c5.staticflickr.com/6/5681/30484942684_316930e4de_c.jpg (https://flic.kr/p/NrRio5)20161127_190556 (https://flic.kr/p/NrRio5) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
RothwellAudio
05-12-2016, 11:08
I looked online but couldn't find a circuit diagram. Anyone have one?
Not that I know of, Andrew. Given the circuit is so basic, isn't it possible to trace it from a good close-up picture of the components on the PCB? :)
Marco.
RothwellAudio
05-12-2016, 12:07
Yes, a good close up picture of the PCB with a light behind it (to show the PCB tracks) might be enough, but it's often difficult to get component values from a picture. But with so many people in this thread having worked on the Lentek I thought someone would have a circuit diagram.
Arkless Electronics
05-12-2016, 13:03
Indeed. If we can get suitable photos of it to be able to trace the circuitry (I've a very good idea what it is already), I'll offer to build clones of them for anyone interested, if the profit margin is enough.... It would not be worth my while to build them anywhere near as cheap as the second hand price of the real thing so probably a commercial non starter..... and I can build better ones of my own design anyway.... but people seem to like 'em, Lentek are long defunct, and the wolf must be kept from the door...
Nice idea, Jez, which I'm sure would be appreciated :)
The trouble is a) finding someone with a Lentek willing to fully remove the PCB from its housing in order to photograph it properly, and b) with the necessary photographing skills (and camera) to take a good enough picture of what's needed.
Sadly, I suspect that such people are in short supply, but you never know! A better idea might be for one of you guys to obtain a Lentek on Ebay, trace the circuit yourselves, and then produce your own units from that basis.
I'm sure that the 'donor unit' originally purchased could be successfully sold later here on AoS, as the Lentek has somewhat of a cult following, so no-one need be out of pocket long term, and if your own units catch on, then you'll be quids in from there! :cool:
A classic example in business of 'speculate to accumulate'.
Marco.
RothwellAudio
05-12-2016, 14:16
A better idea might be for one of you guys to obtain a Lentek on Ebay, trace the circuit yourselves, and then produce your own units from that basis.
I wasn't intending on copying the Lentek - I already produce the Headspace http://www.rothwellaudioproducts.co.uk/html/headspace_mc_headamp.html
My idea was to simply draw out the circuit so I could suggest any sensible mods based on knowing the circuit. Of course, I would also post the circuit diagram on the forum for the benefit of anyone interested.
Arkless Electronics
05-12-2016, 14:49
I also already make much better head amps than the Lentek, which I don't rate, but which seems very popular for some bizarre reason. I'm just cynically trying to make some money by copying a very simple circuit for a long dead product...(I can probably get the circuit from already published photos) and not expecting a single sale... but shy bairns get nowt... hey whose likely to pay me say £200 to make a new Lentek when they can buy a second hand one for £60? It's worth offering though just in case a few people do want them.
Head amps seem a very unpopular niche product in general, many people believe (very wrongly in my opinion) that SUT's are better and many don't seem to understand what they are and think they're for headphones!
RothwellAudio
05-12-2016, 15:45
Head amps seem a very unpopular niche product in general, many people believe (very wrongly in my opinion) that SUT's are better and many don't seem to understand what they are and think they're for headphones!
Yes, indeed, headamps are a very niche product. There days there are so many mc compatible phonostages around that there seems there's hardly any point in getting a headamp. Of course, most valve phonostages are mm only so some kind of headamp or step-up is essential if you want to use an mc cartridge, but I have no idea what they're using - they're certainly not buying a lot of headamps or step-up transformers from me! :rolleyes:
RothwellAudio
05-12-2016, 15:47
... but shy bairns get nowt...
Yes - something for us all to bear in mind :)
I wasn't intending on copying the Lentek - I already produce the Headspace http://www.rothwellaudioproducts.co.uk/html/headspace_mc_headamp.html
My idea was to simply draw out the circuit so I could suggest any sensible mods based on knowing the circuit. Of course, I would also post the circuit diagram on the forum for the benefit of anyone interested.
Indeed, and that would be great, if you are at all able to do so. I was only suggesting the most likely way of gaining access to the circuit for tracing, as I suspect if you're waiting for anyone to produce said required picture, the wait could be a long one! ;)
Marco.
I also already make much better head amps than the Lentek, which I don't rate, but which seems very popular for some bizarre reason.
It's popular because it sounds bloody good, and it's cheap! ;)
Perhaps at the next NEBO you could bring one of your head amps along and test it against the Lentek and I (along with others present) will give you our honest opinion? :)
I'm just cynically trying to make some money by copying a very simple circuit for a long dead product...(I can probably get the circuit from already published photos) and not expecting a single sale...
Nothing wrong with the former - it's called 'supply the demand' (and perfectly good business sense), although in this instance the demand is small. However, head amps/SUTs, and such devices, are discussed more on AoS than on any other forum I know, so if you're going to sell any, it'll be here...
In terms of the last bit (highlighted in bold), you've got the concept all wrong, and I've been meaning to mention this to you for a while. With these types of bespoke products it's completely unrealistic, mate, to expect people just to automatically buy whatever it is you're offering, without first listening to it themselves.
Therefore, if you're offering to copy the Lentek circuit, then if you want sales, you'll have to MAKE ONE FIRST (as a demo unit), then send it out to people interested [let it do a 'round robin'], just as Alan (Firebottle) does with his stuff, and allow the users themselves to decide if its any good or not, or indeed as good as an actual Lentek. People have to use *their ears* to make their own choices, not just be 'told by an expert' what's best.....
I've no doubt that it would be just as good or better, but you have to put the product out there first, and allow it to be assessed, before any likelihood of sales will happen. That's just how it works, hence my reference earlier to 'speculate to accumulate'. If you're not willing to do that, then I completely understand, but it's the *only* way you'll generate sales for such items.
However, if you could get the circuit from already published photos, and publish it here for reference, then that would be a nice thing to do for the AoS community, and a way of showing thanks for the support your business has been given, especially in hard times before you came here (think what happened on pfm) :cool:
Marco.
Arkless Electronics
05-12-2016, 16:24
Yes, indeed, headamps are a very niche product. There days there are so many mc compatible phonostages around that there seems there's hardly any point in getting a headamp. Of course, most valve phonostages are mm only so some kind of headamp or step-up is essential if you want to use an mc cartridge, but I have no idea what they're using - they're certainly not buying a lot of headamps or step-up transformers from me! :rolleyes:
Nor from me! Head amps that is... I don't make SUT's... But of course if a Lentek one comes up it is snatched up in minutes cos it has the "approved brand name"! Well I'm making my forthcoming full function hybrid pre (a shoot off from this will be a phono stage and a line stage) as MM only due to the current fad for using MM stages with separate head amps or (more likely) SUT's, so it will be interesting to see how that goes.... I'll probably offer a matching head amp for that which takes its power from the main unit and maybe a MC only version, which would be a fair bit more expensive as it would probably need an external PSU. I generally make MM only or MC only phono stages BTW as I consider it too large a compromise to do otherwise.
Firebottle
05-12-2016, 16:50
It's popular because it sounds bloody good, and it's cheap! ;)
Marco took his to MiBO so I got to hear for the first time what the appeal is about the Lentek. I swapped my Firebottle 2000 head amp in directly afterwards as a comparison (who wouldn't :rolleyes:) and it was a very interesting comparison. Not a huge difference as I may have been expecting.
I thought the FB 2000 gave a 'smoother' presentation but the Lentek majored on boogie factor and musicality. Difficult to quantify 'musicality' but certainly a good sound :)
337alant
05-12-2016, 16:54
Here are some notes I made when I was repairing Steve's
I should have sketched it out at the time
Note i dont know what the NPN transistors are as there is no markings
https://c7.staticflickr.com/6/5596/31069155230_287815a239_b.jpg (https://flic.kr/p/Pktxqb)LENTEK HEAD A MP (https://flic.kr/p/Pktxqb) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Pic of the underside
https://c2.staticflickr.com/6/5572/30629702713_c0d39748cc_b.jpg (https://flic.kr/p/NEDeuD)IMG_2683 (https://flic.kr/p/NEDeuD) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
Marco took his to MiBO so I got to hear for the first time what the appeal is about the Lentek. I swapped my Firebottle 2000 head amp in directly afterwards as a comparison (who wouldn't :rolleyes:) and it was a very interesting comparison. Not a huge difference as I may have been expecting.
I thought the FB 2000 gave a 'smoother' presentation but the Lentek majored on boogie factor and musicality. Difficult to quantify 'musicality' but certainly a good sound
That's very honest of you to say so, Alan, and I completely concur with your summary of what was heard at MiBO :)
As I said before, the Lentek also gives my £1500 Paul Hynes head amp/off-board linear PSU a hard time, and that, like your FB 2000, is a superb sounding piece of kit. I think you'll agree that, also like you, I know a good sound when I hear it. Furthermore, I'm not using one because I can't afford anything else better either! ;)
So there's a bloody good reason why the Lentek is discussed here so often....... Fact is, it *deserves* it :exactly:
Marco.
Arkless Electronics
05-12-2016, 17:20
It's popular because it sounds bloody good, and it's cheap! ;)
Perhaps at the next NEBO you could bring one of your head amps along and test it against the Lentek and I (along with others present) give you our honest opinion? :)
Nothing wrong with the former - it's called 'supply the demand', although the demand in this instance is small. However, head amps/SUTs and such devices are discussed on AoS than on any other forum I know, so if you're going to sell any, it'll be here...
In terms of the last bit, you've got the concept all wrong, and I've been meaning to mention this to you for a while. With these types of bespoke products it's completely unrealistic, mate, to expect people just to automatically buy whatever it is you're offering, without first listening to it themselves.
Therefore, if you're offering to copy the Lentek circuit, then if you want sales, you'll have to MAKE ONE FIRST (as demo unit), then send it out to people interested, just as Alan (Firebottle) has done with his stuff, and let the users themselves decide if its any good or not, or indeed as good as an actual Lentek.
I've not doubt that it would be, but you have to put the product out there first, and allow it to be assessed, before any likelihood of sales will happen. That's just how it works, hence my reference earlier to 'speculate to accumulate'. If you're not willing to do that, then I completely understand, but it's the *only* way you'll generate sales for such items.
However, if you could get the circuit from already published photos, and publish it here for reference, then that would be a nice thing to do for the AoS community, and a way of showing thanks for the support your business has been given, especially in hard times before you came here (think what happened on pfm) :cool:
Marco.
Ahem... It was I who was doing this first! (and using loading plugs for cartridge matching while I'm at it... not that I was the first)
As far as doing the lentek thing as a thankyou etc well that's what the DIY pre amp was about, as I said in the thread, which I spent probably 30 hours work on and it had no interest so that's a no. The photos on the web I was thinking about, which showed probably enough to work out the circuit, seem to no longer exist so it's academic any way. As I would have been copying a unit that's already popular I can't see why "try before buy" would be necessary.
I would indeed be making them to order only, as with virtually everything I can make. Remember, I have no money. I can't afford to build stuff first and then see if anyone wants to buy it.... Obviously I will be making a hybrid full function pre amp for demo as that is something I consider a "stock product". In the case of the hybrid pre amp though there will be almost unlimited options and upgrades available... which yep.. you guessed it... one will not be able to try before buying when it comes to the options and upgrades... simply not possible! Can you imagine? "I want to try one with the switched attenuator vol control, the bulk foil resistors, twin tape loops and some boutique caps in the phono stage".... yeah I'll just knock one up to that spec at a cost of £800 in parts and 2 weeks labour just so you can hear it and THEN decide whether or not to buy it.... it ain't going to happen.
It occurred to me even when I first mooted the idea that I may have to kill all the upgrade options at birth just to avoid offering so many possibilities that people can't make their mind up... or that all the upgrade options may put some off cos some think that the standard one must be nowt special... No good deed goes unpunished etc!
The one for demo BTW will be a full function pre amp (ie with phono stage and active as well as passive line stage) built to "bog stock" spec other than probably some Mullard NOS valves in it. If someone is interested in just a phono stage then they borrow the full function unit and use it as just a phono stage by feeding the "Tape Out" signal to their own pre amp. If wanting just a line stage then try it but don't connect a TT to the "Phono" input. Simples.
Arkless Electronics
05-12-2016, 17:23
Here are some notes I made when I was repairing Steve's
I should have sketched it out at the time
Note i dont know what the NPN transistors are as there is no markings
From the front view L to R E-C-B
https://c7.staticflickr.com/6/5596/31069155230_287815a239_b.jpg (https://flic.kr/p/Pktxqb)LENTEK HEAD A MP (https://flic.kr/p/Pktxqb) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Pic of the underside
https://c2.staticflickr.com/6/5572/30629702713_c0d39748cc_b.jpg (https://flic.kr/p/NEDeuD)IMG_2683 (https://flic.kr/p/NEDeuD) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
Now that makes it doable but a photo from the top with a light underneath would make it much easier...
337alant
05-12-2016, 17:28
I think you could do a good little MC head amp with a single op amp for each channel :eyebrows:
Alan
Arkless Electronics
05-12-2016, 17:28
Marco took his to MiBO so I got to hear for the first time what the appeal is about the Lentek. I swapped my Firebottle 2000 head amp in directly afterwards as a comparison (who wouldn't :rolleyes:) and it was a very interesting comparison. Not a huge difference as I may have been expecting.
I thought the FB 2000 gave a 'smoother' presentation but the Lentek majored on boogie factor and musicality. Difficult to quantify 'musicality' but certainly a good sound :)
As good as it may well sound, all those caps in the signal path, in a head amp, will be by far the biggest issue holding it back... or adding some colouration that is interpreted as "boogie factor" and "musicality", both IMHO of course:)
Arkless Electronics
05-12-2016, 17:36
I think you could do a good little MC head amp with a single op amp for each channel :eyebrows:
Alan
Easily doable but I reckon it would not sound anything that special. The Arkless 640P kind of works like this and it allows me to offer MM and MC on this without the usual compromises being such a big problem. However, although the Arkless 640P sounds great and is excellent VFM, it is a fairly budget product and I reckon using similar technology in a head amp to place before a £1000+ MM stage would likely hold back the overall performance...
337alant
05-12-2016, 17:43
Now that makes it doable but a photo from the top with a light underneath would make it much easier...
Can't do now Jez unfortunately
Alan
Ahem... It was I who was doing this first! (and using loading plugs for cartridge matching while I'm at it... not that I was the first)
Can't say for certain, but I remember Alan doing it (from almost day one when he joined) before you were here. Guess we could settle it by looking at your respective join dates....
I would indeed be making them to order only, as with virtually everything I can make. Remember, I have no money. I can't afford to build stuff first and then see if anyone wants to buy it....
Yup, and that's fine, but then at the same time don't moan when no-one's buying anything from you because they're expecting what I've stated ;)
Catch 22, dude!
Obviously I will be making a hybrid full function pre amp for demo as that is something I consider a "stock product". In the case of the hybrid pre amp though there will be almost unlimited options and upgrades available... which yep.. you guessed it... one will not be able to try before buying when it comes to the options and upgrades... simply not possible! Can you imagine? "I want to try one with the switched attenuator vol control, the bulk foil resistors, twin tape loops and some boutique caps in the phono stage".... yeah I'll just knock one up to that spec at a cost of £800 in parts and 2 weeks labour just so you can hear it and THEN decide whether or not to buy it.... it ain't going to happen.
Yup, I totally get that. However, could you not offer a stripped down demo version in a 'dog's dinner' format, complete simply with the basics just to let folk hear it, and then 'posh up' the finished article they'd actually get when buying one? :)
The problem you've got Jez is, let's face it, you're not an 'established name', and so very few people are going to buy stuff in advance solely on your say so, no matter how good your gear actually is.
You have to make a name for yourself, to the extent that folk will buy stuff automatically, based on your reputation, and that takes time. It's also why the 'big boys' spend so much on marketing/advertising, and have established large and loyal customer bases, in order that when they announce a new product, their customers flock to buy it.
Unfortunately, you're a very long way from having that sort of clientele - and the only way to get anywhere near that is to get your products out there to as many people as possible, and that means demo units doing the rounds amongst members, and you getting your ass out there to bake-offs. Your stuff isn't selling because it's NOT GETTING HEARD OR TALKED ABOUT enough. Simples.
Give up going the pub for a few months and spend what you save on funding some of the above!... ;) It's the only way you'll achieve what you think you're entitled to. I'm simply being honest with you.
Marco.
Here are some notes I made when I was repairing Steve's
I should have sketched it out at the time
Note i dont know what the NPN transistors are as there is no markings
https://c7.staticflickr.com/6/5596/31069155230_287815a239_b.jpg (https://flic.kr/p/Pktxqb)LENTEK HEAD A MP (https://flic.kr/p/Pktxqb) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Pic of the underside
https://c2.staticflickr.com/6/5572/30629702713_c0d39748cc_b.jpg (https://flic.kr/p/NEDeuD)IMG_2683 (https://flic.kr/p/NEDeuD) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
Nice one, Alan! :clap: :thumbsup:
Marco.
As good as it may well sound, all those caps in the signal path, in a head amp, will be by far the biggest issue holding it back... or adding some colouration that is interpreted as "boogie factor" and "musicality", both IMHO of course:)
That's certainly NOT what I mean when referring to the above.
It's an effect that's fundamental to the music, not a form of coloration. The problem is describing what you hear in words, without it sounding silly.... But it's inevitable unless we all just use measurements or objective data to assess hi-fi equipment or for describing how good something is, and on a forum such as this, populated mostly by subjectivists, that's never gonna happen ;)
Marco.
It's an effect that's fundamental to the music, not a form of coloration. The problem is describing what you hear in words, without it sounding silly.... But it's inevitable unless we all just use measurements or objective data to assess hi-fi equipment or for describing how good something is, and on a forum such as this, populated mostly by subjectivists, that's never gonna happen ;)
Marco.
Indeed, how does one measure, or even define adequately, perceived qualities such as 'musicality', 'boogie factor' or 'PRaT'? How does one measure the ability of a system to display a good soundstage and focus? - measuring interchannel crosstalk only goes a very small way in this regard.
Exactly, Barry. Descriptive language is how subjective audio enthusiasts communicate what they hear when listening to equipment. Sadly, however, it's one many engineers/'objectivists' struggle to comprehend, often much to their commercial loss ;)
Marco.
Arkless Electronics
05-12-2016, 20:27
Can't say for certain, but I remember Alan doing it (from almost day one when he joined) before you were here. Guess we could settle it by looking at your respective join dates....
Yup, and that's fine, but then at the same time don't moan when no-one's buying anything from you because they're expecting what I've stated ;)
Catch 22, dude!
Yup, I totally get that. However, could you not offer a stripped down demo version in a 'dog's dinner' format, complete simply with the basics just to let folk hear it, and then 'posh up' the finished article they'd actually get when buying one? :)
The problem you've got Jez is, let's face it, you're not an 'established name', and so very few people are going to buy stuff in advance solely on your say so. You have to make a name for yourself, to the extent that folk will buy stuff automatically, based on your reputation, and that takes time.
It's also why the 'big boys' spend so much on marketing/advertising, and have established large and loyal customer bases, in order that when they announce a new product, their customers flock to buy it. Unfortunately, you're a very long way from having that sort of clientele - and the only way to get anywhere near that is to get your products out there to as many people as possible, and that means demo units doing the rounds amongst members, and you getting your ass out there to bake-offs.
Give up going the pub for a few months and spend what you save on some of the above!... ;) It's the only way you'll achieve what you think you're entitled to. I'm simply being honest with you.
Marco.
It was Si (SQ23679 whatever) who gave me the idea but all I meant was when you said "why not do the same as Allan and send one around customers" well I was doing just that before him, AFAIK, on pfm. Not that it's a contest or a problem... just sayin' :) I'm sure there were others before me.
The bit I put in bold on your post I'm flabbergasted by!!! The entire reason I've spent hundreds already on the project is because virtually all respondents told me that "no matter how impressed with the sound quality of a scruffy prototype no ones going to buy one without seeing, touching etc the real finished bling looking item. WAF and pride of ownership are that important for most people" :eek::scratch::rolleyes:
The "catch 22's" I'm painfully aware of... as I am of the "success breeds success" maxim. Not much I can do about them. Something I have learned over the last few years is that at the end of the day sound quality and performance count for diddly squat and branding, brand loyalty, recommendation from others and resale value are ultimately all that matters... FFS many seem to want to be told what to buy! But only if it's a major brand name of course... How often do you see something like "I've just bought some Acme MkII speakers. What amp should I buy to go with these?" Usually the ones on their short list will be Rega, Naim etc....
I'll try and make that clearer.... Most modern kit sounds good. There are few "howlers" out there. Most sounds good enough to impress at least a good percentage of potential customers, lets say at least a third think it sounds marvellous, even if only because they have not compared it to something better . That's a lot of people who will buy the kit... but probably only if they've seen it in magazines, read reviews on it, spoke to people on forums about it etc and are certain that it will have a good re-sale value and be easy to shift if they sell.
".....achieve what you think you're entitled to" lol.. a bit of a loaded statement! I guess having been in electronics all my life and most of it specialising in audio electronics, being (even if only IMHO) very good at it etc, I'll admit feeling "entitled" to some success and not permanently skint by now yes! As to the pub.. I wish! About once a week these days.. can't afford it. A few tinnies and roll ups for us poor folks sire :eyebrows:
I was no doubt a daftee coming into this thinking that if I build better than average sounding gear, in fact go all out for "best in class", and for lower than average prices, then I could "beat the system" and not have to "play the game" and customers would flock to my door... I could do it with no money to invest in it... but it doesn't work like that it seems... you have to have enough money initially to buy your success. ie make a dozen bling prototypes, let influential reviewers keep some of them (to get a good review), pay for magazine advertising, pay to have a stand at major shows etc etc.. only by buying this initial "success" (brand awareness etc) does the actual success breed...
Of course the fact that my people skills, marketing skills and knowing when to STFU etc etc are not only poor but a benchmark for how not to do it doesn't help!! If I was a "D-" electronic engineer but had the gift of the gab, irresistible charm and the ability to sell sand to Arabs I'd probably be doing very well by now:eek:
My plans at the moment are to push ahead with the hybrid pre amp and maybe a follow up SS MC only "giant killer" phono stage at about £600, but, to be honest, I'm getting near the end of my tether with the whole game and so if, as I've learned to cynically expect by now, only maybe 4 people even want to listen to it, they all say it's the best they've heard anywhere near its price point..... but don't want to buy one.... I reckon a career change of some sort may (reluctantly) be in order:rolleyes: For now though it's "this time next year eh Rodney!?" and hope that the hybrid pre takes off!
Arkless Electronics
05-12-2016, 20:35
So is anyone reverse engineering the Lentek now? if not I may end up doing it when bored some time:)
I'm with you in many areas there, Jez, although in some you're being a touch too cynical, IMO, although given what you've experienced to date, understandably so. If I get time later I'll reply in more detail :)
Marco.
Arkless Electronics
05-12-2016, 20:47
I'm with you in many areas there, Jez, although in some you're being a touch too cynical, IMO, although given what you've experienced to date, understandably so. If I get time later I'll reply in more detail :)
Marco.
I'd appreciate the input there Marco:)
Floyddroid
05-12-2016, 22:08
Isn't that taking the piss though Jez?
I also already make much better head amps than the Lentek, which I don't rate, but which seems very popular for some bizarre reason. I'm just cynically trying to make some money by copying a very simple circuit for a long dead product...(I can probably get the circuit from already published photos) and not expecting a single sale... but shy bairns get nowt... hey whose likely to pay me say £200 to make a new Lentek when they can buy a second hand one for £60? It's worth offering though just in case a few people do want them.
Head amps seem a very unpopular niche product in general, many people believe (very wrongly in my opinion) that SUT's are better and many don't seem to understand what they are and think they're for headphones!
Arkless Electronics
06-12-2016, 01:40
Isn't that taking the piss though Jez?
When in Rome... "pal".
Oi - let's keep the vibe nice and friendly, guys!
Marco.
RothwellAudio
07-12-2016, 09:23
Here are some notes I made when I was repairing Steve's
I should have sketched it out at the time
Note i dont know what the NPN transistors are as there is no markings
Alan
Thanks for the pictures. I tried to work out the circuit last night but it proved very difficult without being able to see the component side of the board and the tracks together. I failed miserably :doh:
Arkless Electronics
07-12-2016, 14:08
I'm working on it and about 2/3rd's of the way there. I expect to post the diagram today. Indeed it is not easy!
I did ask before starting if anyone else is also planning to attempt it in order to avoid the prospect of two or more of us "wasting" hours on the same task...
Arkless Electronics
07-12-2016, 17:14
Here yer go folks...
http://i1303.photobucket.com/albums/ag156/Jez1235/Lentek%20Head%20Amp%207-12-16_001_zpsy7nindoo.jpg (http://s1303.photobucket.com/user/Jez1235/media/Lentek%20Head%20Amp%207-12-16_001_zpsy7nindoo.jpg.html)
Edit: C1,2,3,4 marked 10uF are 47uF
Nice one, Jez. Much appreciated! :thumbsup:
So when are you building one for us to listen to? ;)
Marco.
Arkless Electronics
07-12-2016, 18:20
Nice one, Jez. Much appreciated! :thumbsup:
So when are you building one for us to listen to? ;)
Marco.
The design is better in terms of potential sound quality than I had assumed... but has it's issues and limitations...
The ZTX transistors are not the original type of course but I put them in the diagram cos they would probably work pretty well in this application and are readily available. All values are as in original Lentek. Resistor etc for battery check led not shown.
I've no plans to build any as such but if anyone wants to commission one then I'll take the job of course. I would vastly prefer to supply just a tested board for people to put in their own casework. Various component types and values would be upgraded compared to a standard one, along similar lines to those modded by Nick. £80 delivered for board only.
The possibility of a "Lentek Head Amp; The Arkless Edition" is of course present.... with all sorts of improvements to the original. It's just a push pull common emitter amplifier at the end of the day and various compromises are present to make it a bit cheaper and allow the use of just the one battery. It should be possible to make one with some extra "house-keeping" circuitry and twin 9V batteries or mains PSU which would be considerably better than the original but at a much higher price etc..
Arkless Electronics
07-12-2016, 19:11
I wonder how long it will take for a Chinese made clone at £7.50 to appear now? :D
The design is better in terms of potential sound quality than I had assumed... but has it's issues and limitations...
That's reassuring, as I didn't think I was deaf :D;)
Limitations? Of course, as with any piece of hi-fi equipment, especially a budget design like that.
The possibility of a "Lentek Head Amp; The Arkless Edition" is of course present.... with all sorts of improvements to the original. It's just a push pull common emitter amplifier at the end of the day and various compromises are present to make it a bit cheaper and allow the use of just the one battery. It should be possible to make one with some extra "house-keeping" circuitry and twin 9V batteries or mains PSU which would be considerably better than the original but at a much higher price etc..
I like the idea of the twin battery thing, as it's something I've also contemplated recently, so might take you up on that :cool:
Marco.
Arkless Electronics
07-12-2016, 19:50
That's reassuring, as I didn't think I was deaf :D;)
Limitations? Of course, as with any piece of hi-fi equipment, especially a budget design like that.
I like the idea of the twin battery thing, as it's something I've also contemplated recently, so might take you up on that :cool:
Marco.
The twin battery idea I'm talking about is 100% different to that which you are no doubt talking about and involves a complete redesign of the circuitry whilst keeping the basic topology. It would likely only be practical in a new Arkless version. However, there are reasons why twin batteries as you are probably talking about would also be an improvement yes.... if they will fit! A new on/off switch would have to be fitted as well.
Arkless Electronics
07-12-2016, 20:00
Probably the biggest improvement one could make to a standard Lentek would be to replace the emitter capacitors with film types such as polypropylene. In Nicks mods he increases them from the standard 10uF ( I haven't been able to read the lettering on these caps so I don't know 100% that these are originally 10uF but I would put a lot of money on it that I'm right!) with 47uF ones , as I would also, and the issue here is a purely physical one... together, the 4 caps would be bigger than the whole head amp!! Re-boxing it in a much larger case would be required.
Edit: I may have lost a lot of money on that bet as well!! In close up photos of the original innards all the tantalum caps look identical (it's a pity the photos at the beginning of the thread are gone!) and as most are marked as 10uF in Alan's photos (which have some errors BTW) I have assumed all the identical looking originals are 10uF....
HOWEVER.... If this is correct then the original version was -3dB @ 50Hz!! The 47uF ones are suitable...
As with most cap types, tants get bigger as they go up in capacitance and/or voltage rating. It is possible that the originals were indeed 47uF but at probably 6V rating whilst the identical looking ones at 10uF are rated for 10 or 16 Volts... It would be interesting if anyone can confirm. Neither is even slightly critical and the more capacitance the better in both cases. All other values I am certain about as clear enough views of the parts were available.
The twin battery idea I'm talking about is 100% different to that which you are no doubt talking about and involves a complete redesign of the circuitry whilst keeping the basic topology. It would likely only be practical in a new Arkless version. However, there are reasons why twin batteries as you are probably talking about would also be an improvement yes.... if they will fit! A new on/off switch would have to be fitted as well.
I hear ya, and cool. We'll cross that bridge when we come to it. I'm probably more focussed on the Celestion mods at the moment, but further surgery on the Lentek will come soon after that :)
Marco.
Arkless Electronics
07-12-2016, 20:32
Marco, do you find the output rather healthy from the Lentek? Simulation predicts 28dB gain....
Yes, very healthy - and I like that. We've been here before, in terms of a healthy gain contributing to a 'punchy' sound, as opposed to the opposite, when it's 'weedy' ;)
That effect, however, will be very cartridge and/or partnering phono stage dependent.
Marco.
Arkless Electronics
07-12-2016, 20:47
Yes, very healthy - and I like that. We've been here before, in terms of a healthy gain contributing to a 'punchy' sound, as opposed to the opposite, when it's 'weedy' ;)
That effect, however, will be very cartridge and/or partnering phono stage dependent.
Marco.
Hmmm... well as you know this is one of the (many! :D) things on which we disagree.. my question was purely to see if the output seems as healthy in practice as computer simulation predicted and I would have been amazed if it wasn't. Sims predict THD of 0.002% BTW. No flies on that!
It could be made much less hissy if battery life was not an issue ;)
Hehehe... Hiss has always been a factor with the Lentek, so anything which notably reduces that, or nullifies it, would be great :)
The key for me with the Lentek is to maintain its rather 'feisty' and upfront way of music-making [not sucking the life out of it], whilst injecting it with a soupçon more resolution and refinement. That's certainly the goal I have with mine.
Marco.
Arkless Electronics
07-12-2016, 21:05
Hehehe... Hiss has always been a factor with the Lentek, so anything which notably reduces that, or nullifies it, would be great :)
The key for me with the Lentek is to maintain its rather 'feisty' and upfront way of music-making [not sucking the life out of it], whilst injecting it with a soupçon more resolution and refinement. That's certainly the goal I have with mine.
Marco.
Compromises as ever in engineering.... No hiss is impossible for a start! Reducing it means reduced battery life....
Yup, sure. Hence why the twin battery idea is of interest.
Marco.
Light Dependant Resistor
07-12-2016, 22:05
Yes but as usual, serious circuit analysis missing.:rolleyes:
The circuit suggests it is a Class C device with no DC bias, rather just being turned on by
the cartridge signal. It would be nice to see it instead as a common base design -which it hints at, where voltage
increases, emitter then being input and collector the output. Better though as common base with a dual rail supply.
Also way too many RC time constants. Capacitors have their place in power supplies not in audio circuits
where they can be if carefully designed,can be totally avoided.
Fets and mosfets ( and variants like implementing cascodes ) being a much better choice as amplifying devices, for audio circuits.
Arkless Electronics
08-12-2016, 02:12
Yes but as usual, serious circuit analysis missing.:rolleyes:
The circuit suggests it is a Class C device with no DC bias, rather just being turned on by
the cartridge signal. It would be nice to see it instead as a common base design -which it hints at, where voltage
increases, emitter then being input and collector the output. Better though as common base with a dual rail supply.
Also way too many RC time constants. Capacitors have their place in power supplies not in audio circuits
where they can be if carefully designed,can be totally avoided.
Fets and mosfets ( and variants like implementing cascodes ) being a much better choice as amplifying devices, for audio circuits.
Oh dear..... It's not class C, it's class A. The "cartridge signal" couldn't turn anything on or bias anything....
Common base would work equally well yes, and many variants of the Lentek circuit and similar common base ones are extant. Common base would make it virtually impossible to change cartridge loading though, and the gain would vary considerably with cartridge source resistance. I've not simulated it but a glance at the circuitry says to me that the standard Lentek input loading is roughly 90 Ohms.
Dual rail supplies are what I was hinting at to Marco earlier but getting the full benefits are rather more awkward than at first glance in this topology...
Whilst there are all sorts of obvious compromises, I can see exactly why, under the circumstances of it having to be small, powered by just a PP3 for a good long while and relatively cheap, they choose the blend of compromises that they did. Poor noise performance and needing electrolytics or tantalums in sensitive areas are the most salient down sides of the compromises.
For best results this circuit would also need the transistors to be not only selected for low noise (partial get round by choosing known very low noise devices and taking pot luck), but also carefully matched for gain and Vbe. It can give an output offset voltage of several millivolts, which could upset some following MM stages if DC coupled. Matching would help hugely with this, as well as overall SQ, but the devices should be thermally bonded for good thermal tracking.
Cascoding would be irrelevant to this topology and just be noisier and twice as complicated etc.
Good luck with building a mosfet head amp BTW :eek:
Light Dependant Resistor
08-12-2016, 03:40
Oh dear..... It's not class C, it's class A. The "cartridge signal" couldn't turn anything on or bias anything....
Common base would work equally well yes, and many variants of the Lentek circuit and similar common base ones are extant. Common base would make it virtually impossible to change cartridge loading though, and the gain would vary considerably with cartridge source resistance. I've not simulated it but a glance at the circuitry says to me that the standard Lentek input loading is roughly 90 Ohms.
Dual rail supplies are what I was hinting at to Marco earlier but getting the full benefits are rather more awkward than at first glance in this topology...
Whilst there are all sorts of obvious compromises, I can see exactly why, under the circumstances of it having to be small, powered by just a PP3 for a good long while and relatively cheap, they choose the blend of compromises that they did. Poor noise performance and needing electrolytics or tantalums in sensitive areas are the most salient down sides of the compromises.
For best results this circuit would also need the transistors to be not only selected for low noise (partial get round by choosing known very low noise devices and taking pot luck), but also carefully matched for gain and Vbe. It can give an output offset voltage of several millivolts, which could upset some following MM stages if DC coupled. Matching would help hugely with this, as well as overall SQ, but the devices should be thermally bonded for good thermal tracking.
Cascoding would be irrelevant to this topology and just be noisier and twice as complicated etc.
Good luck with building a mosfet head amp BTW :eek:
The transistors as provided in your schematic are not in their active region, as there is no DC bias to the base.
Either you have the schematic drawn wrongly, or need a few minutes refreshing your knowledge of transistor biasing
if still asserting Class A. Here is a nice tutorial https://www.youtube.com/watch?v=c6cmkm3UPUI
Where a transistor lacks bias to the base, as your schematic shows tied approx 150-200 ohms from ground,
( that is a strange arrangement for each channels stage sharing a resistor prior to ground )
- the transistor circuit is Class C but would be requiring a preceding amplifier stage and would be hopeless
in terms of audio fidelity... we both agree I think. Perhaps you should look at how the transistors
are achieving bias, as there is a bit of mystery at the moment.
The other exception and would be quite a good circuit, is the common base form allowing voltage gain
Here the emitter of the transistor is the input and the collector the output. Best though with a dual rail supply
http://www.allaboutcircuits.com/textbook/semiconductors/chpt-4/common-base-amplifier/
Cheers / Chris
337alant
08-12-2016, 07:48
Probably the biggest improvement one could make to a standard Lentek would be to replace the emitter capacitors with film types such as polypropylene. In Nicks mods he increases them from the standard 10uF ( I haven't been able to read the lettering on these caps so I don't know 100% that these are originally 10uF but I would put a lot of money on it that I'm right!) with 47uF ones , as I would also, and the issue here is a purely physical one... together, the 4 caps would be bigger than the whole head amp!! Re-boxing it in a much larger case would be required.
Edit: I may have lost a lot of money on that bet as well!! In close up photos of the original innards all the tantalum caps look identical (it's a pity the photos at the beginning of the thread are gone!) and as most are marked as 10uF in Alan's photos (which have some errors BTW) I have assumed all the identical looking originals are 10uF....
HOWEVER.... If this is correct then the original version was -3dB @ 50Hz!! The 47uF ones are suitable...
As with most cap types, tants get bigger as they go up in capacitance and/or voltage rating. It is possible that the originals were indeed 47uF but at probably 6V rating whilst the identical looking ones at 10uF are rated for 10 or 16 Volts... It would be interesting if anyone can confirm. Neither is even slightly critical and the more capacitance the better in both cases. All other values I am certain about as clear enough views of the parts were available.
Jez
Only the 2 inner tantalum were 10uf
the 4 outer ones are 47uf as identified in my photo
In post 120 I listed the caps
http://theartofsound.net/forum/showthread.php?8431-Nick-G-modified-Lentek-Head-Amp&p=790152#post790152
Alan
RothwellAudio
08-12-2016, 10:55
Well done Jez for working out the circuit from those two pictures - not easy at all.
However, I don't get it. I think I'll be staring at that diagram a while before I work out how it works :scratch:
Arkless Electronics
08-12-2016, 12:01
Jez
Only the 2 inner tantalum were 10uf
the 4 outer ones are 47uf as identified in my photo
In post 120 I listed the caps
http://theartofsound.net/forum/showthread.php?8431-Nick-G-modified-Lentek-Head-Amp&p=790152#post790152
Alan
Thanks Alan. Circuit sims said they had to be really but it's nice to have it confirmed ;) Some close up photo's I saw which unfortunately didn't show the values had all the tants looking identical and I at first assumed the increase to 47uF was due to Nick having made the decision to change them.
I;ve now added a note to the post with the circuit diagram correcting this.
Arkless Electronics
08-12-2016, 12:35
The transistors as provided in your schematic are not in their active region, as there is no DC bias to the base.
Either you have the schematic drawn wrongly, or need a few minutes refreshing your knowledge of transistor biasing
if still asserting Class A. Here is a nice tutorial https://www.youtube.com/watch?v=c6cmkm3UPUI
Where a transistor lacks bias to the base, as your schematic shows tied approx 150-200 ohms from ground,
( that is a strange arrangement for each channels stage sharing a resistor prior to ground )
- the transistor circuit is Class C but would be requiring a preceding amplifier stage and would be hopeless
in terms of audio fidelity... we both agree I think. Perhaps you should look at how the transistors
are achieving bias, as there is a bit of mystery at the moment.
The other exception and would be quite a good circuit, is the common base form allowing voltage gain
Here the emitter of the transistor is the input and the collector the output. Best though with a dual rail supply
http://www.allaboutcircuits.com/textbook/semiconductors/chpt-4/common-base-amplifier/
Cheers / Chris
"Better to remain silent and be thought a fool than to speak out and remove all doubt" Lincoln/Twain
Paul Hynes
08-12-2016, 13:28
I have to side with Jez on this.
The Lentek circuit is simple and elegant in its concept. Input DC bias is from one base to the other and the base terminals are referenced to ground by the 100R to ground in parallel with the cartridge impedance. The output swing is limited to 2x base/emitter voltages less the collector/emitter saturation voltages of the transistors, but this is more than sufficient for the signal levels in operation. The collector/emitter current is provided via the 15K resistors, which also balance the battery voltage around ground to give a split rail supply to the transistors. The output voltage is developed across the 4K7 collector load resistor.
The resistors used in Alan’s photos are thick film and metal oxide types which were available from RS components back when the Lentek was manufactured.
Paul
http://hoone.com/lentek_pre-pre_circuit.jpg
Found on the Internet. This is supposed to show one channel for the Lentek.
Arkless Electronics
08-12-2016, 14:19
As this simple circuit seems to be causing consternation and confusion I'll explain how it works.
It is a pair of common emitter amplifiers working in push pull. The collector of each device provides a very high impedance active load for the complementary device and renders the whole a virtual transconductance amplifier (it would be more nearly a true transconductance stage if common base but close enough). The 4k7 resistor to "ground" in effect sets the gain by deriving an output voltage proportional to the current according to Mr Ohm.. The 100R resistor to "ground" from the middle of the 47uF caps on the emitters also helps to set gain by providing some AC only degenerative feedback. Without the 4k7 at the collectors there would be no overall change in current from which to derive this current-controlled-voltage-applied feedback and so the 4k7 and 100R work together to set gain.
Getting down to mega basics, a transistor (npn) is forward biased when we reach the Vbe of approx 0.65V + a wee bit to give some base current. Now Vbe is "Voltage between base and emitter", all that is required is for the base to be 0.65V positive with respect to the emitter .... you can ground the base and then take the emitter 0.65V NEGATIVE to achieve the same effect ;)
Power is applied from the 9V battery via the two 15K resistors to the emitters and it is these resistors that set the bias and in effect act as a voltage divider with equal upper and lower resistor values, this assists in forming a floating "ground" (hence the quotation marks), in association with AC decoupling from the two 10uF tants. In effect it is working from +4.5V and -4.5V supplies and the whole thing is floating, the AC midpoint for each channel being derived from the centre point of the 47uF tants via the 100R resistor.
The 15K resistors provide a huge amount of DC degenerative feedback to each transistor and hence bugger all gain at DC (the 47uF tants decouple this at AC), which is good as we don't want to amplify the offset voltage, and the complementary npn pnp pair means the offsets cancel at both input and output, to the accuracy of the transistor matching anyway!
Simple but in a satisfyingly elegant way! :)
And incidentally very similar to the input stage of "The Paradise" MC phono stage.... except that doesn't need to "float".
Arkless Electronics
08-12-2016, 14:23
Well I'll go to the bottom of our stairs...
Another explanation and a circuit diagram (which is correct... a few values are different probably due to being a different "Mk") have appeared whilst I typed away... stopping for coffees and tabs here and there, over an hour or more... Took me about 3 hours to reverse engineer it and do that schematic 'n all...:doh:
Arkless Electronics
08-12-2016, 14:31
I have to side with Jez on this.
The Lentek circuit is simple and elegant in its concept. Input DC bias is from one base to the other and the base terminals are referenced to ground by the 100R to ground in parallel with the cartridge impedance. The output swing is limited to 2x base/emitter voltages less the collector/emitter saturation voltages of the transistors, but this is more than sufficient for the signal levels in operation. The collector/emitter current is provided via the 15K resistors, which also balance the battery voltage around ground to give a split rail supply to the transistors. The output voltage is developed across the 4K7 collector load resistor.
The resistors used in Alan’s photos are thick film and metal oxide types which were available from RS components back when the Lentek was manufactured.
Paul
Spot on Paul ;) and yes indeed max output is +/- one Vbe peak to peak so roughly 1V peak to peak and therefore 350mV RMS. Agreed.
I seem to recall those 2% resistors being sold as "thick film metal glaze" at the time....
Arkless Electronics
08-12-2016, 14:48
I'm not keen on the R11, C7 arrangement... No doubt for ground loop avoidance reasons and yes the two channels grounds will no doubt meet at the MM input of the following amp, but it gives a a bit of a tortuous path for the return to the decoupling of the pair of 10uF tants for one channel and not the other... Prob nowt to worry about but not ideal.
RothwellAudio
08-12-2016, 14:55
The diagram posted by Juha make things look a bit less confusing to me and now I'm getting it. :eyebrows:
Thanks for the explanations.
Arkless Electronics
08-12-2016, 15:06
The diagram posted by Juha make things look a bit less confusing to me and now I'm getting it. :eyebrows:
Thanks for the explanations.
Good :) Yes it's an easier to understand diagram.... I just wish I'd googled longer and found it hence saving myself a few hours work!
To clarify on the biasing, the base current indeed flows from one base to the other as Paul said, it has nowhere else to go, (other than a minute amount flowing to ground through the cart and 100R resistor due to input offset) but is derived and set as in my explanation. Both are correct but I hope that clarifies that we're both actually talking about the same thing...
RothwellAudio
08-12-2016, 15:31
BTW, there's a very similar circuit here:
http://leachlegacy.ece.gatech.edu/headamp/
It's The Common Emitter Circuit at the bottom of the page. It's drawn differently again, but is actually very similar.
There's also an interesting analysis of this type of circuit here:
http://www.audiomisc.co.uk/Armstrong/reviews/finale/1982.html
It's the stuff in the white boxes.
Of course, Jez, Paul Hynes etc. don't need the explanation and most of the other forum members probably aren't interested in going that deep into how the circuit works, but I thought I'd post the links in case anyone wants to explore some variations on the Lentek theme.
BTW Jez, you need to "spend a few minutes refreshing your knowledge of transistor biasing". :lol:
Arkless Electronics
08-12-2016, 16:13
BTW, there's a very similar circuit here:
http://leachlegacy.ece.gatech.edu/headamp/
It's The Common Emitter Circuit at the bottom of the page. It's drawn differently again, but is actually very similar.
There's also an interesting analysis of this type of circuit here:
http://www.audiomisc.co.uk/Armstrong/reviews/finale/1982.html
It's the stuff in the white boxes.
Of course, Jez, Paul Hynes etc. don't need the explanation and most of the other forum members probably aren't interested in going that deep into how the circuit works, but I thought I'd post the links in case anyone wants to explore some variations on the Lentek theme.
BTW Jez, you need to "spend a few minutes refreshing your knowledge of transistor biasing". :lol:
:) :eyebrows: :D
Yep I did say there were "many similar circuits extant"... including from Leach, Linsley-Hood and Cherry...
Some respect due to Lentek over their choice of transistors (of those available then). I mentioned the need for good matching of the complements and Lentek have chosen ostensibly "non-complements" to give actual improved complementarity by the time consuming (at R+D level) process of finding transistors from different families that actually are more complementary than the obvious solution... hence the removing of type numbers from one or both devices ;)
Tis' a pity that for reasons of battery life, size and price the collector current is so low as to make it so hissy...
Paul Hynes
08-12-2016, 17:18
Jez,
The resistors with the brown body in Alan’s photo were indeed thick film metal glaze. The resistors with the grey body were metal oxide. I still have quite a few of both of these resistor types in my old R&D component draws from the 1980s/1990s.
Arkless Electronics
08-12-2016, 17:32
Jez,
The resistors with the brown body in Alan’s photo were indeed thick film metal glaze. The resistors with the grey body were metal oxide. I still have quite a few of both of these resistor types in my old R&D component draws from the 1980s/1990s.
I've still got a fair few of the metal oxide ones myself and well remember ordering and using the thick film metal glaze ones (from RS yes) to build a John Linsley Hood designed dual rail voltage regulator for a power amp when I was about 18.... I've still got the board somewhere.
Also have boxes of 70's NOS "glass tin oxide" resistors which no doubt is proprietary term for metal oxide...
Paul Hynes
08-12-2016, 17:41
Jez, I guess you are a hoarder too!
Incidentally, for anyone considering building a Lentek head amp for themselves, the 2SA1085 and 2SC2547 with a source impedance of 100R both have a noise factor (NF) of around 0.5 dB and they are effectively operating in parallel for noise purposes, so the averaged noise contribution would be less than 0.5 dB without a cartridge connected. The noise level would rise slightly with a low impedance cartridge connected but would still be acceptable. These transistors are not current production items but they can still be sourced from surplus outlets.
Arkless Electronics
08-12-2016, 18:01
Jez, I guess you are a hoarder too!
Incidentally, for anyone considering building a Lentek head amp for themselves, the 2SA1085 and 2SC2547 with a source impedance of 100R both have a noise factor (NF) of around 0.5 dB and they are effectively operating in parallel for noise purposes, so the averaged noise contribution would be less than 0.5 dB without a cartridge connected. The noise level would rise slightly with a low impedance cartridge connected but would still be acceptable. These transistors are not current production items but they can still be sourced from surplus outlets.
I'm a total hoarder of components yes!
Agreed on all your other comments.. Hitachi devices IIRC.... There are lower Rb's devices such as the Rohm 2SB737 but it's also discontinued and complements are sketchy... A more readily available pair that could work well are the old standby of 2N4401/03 but the ZTX devices I put in my diagram are decent too. Neither are as good as the more difficult (but not that difficult) to find devices you mentioned though... and lack of current is still the Achilles heel of this design in its original form, noise wise...
The way that the "digital revolution" has killed off the manufacture of almost all the best devices for low noise audio is much lamented by myself, and no doubt most other engineers in the field.. even with a little light at the end of the tunnel from Linear Systems... Maybe the rise in vinyl sales , if it continues, will mean big companies like Sony, Pioneer etc etc starting to make amps with MC phono stages once again in quantity and give the semi makers a reason to bring them back... but I won't hold my breath!
It's tempting sometimes to design with the best devices for the job, even if they're obsolete, on the grounds that I can get enough to make maybe 10 units no problem (or have them in stock) but then there's the worry of "what if this is the product that takes off?"....
Yes, very healthy - and I like that. We've been here before, in terms of a healthy gain contributing to a 'punchy' sound, as opposed to the opposite, when it's 'weedy' ;)
That effect, however, will be very cartridge and/or partnering phono stage dependent.
Marco.
Interesting, never thought of it like that, but now I come to think of it, now I realise why my HiFi wakes up so quickly, and why I enjoy it compared to when I had to crank things up just for a decent volume.
Sent from my SM-G920F using Tapatalk
Hi Paul,
I have to side with Jez on this.
The Lentek circuit is simple and elegant in its concept.
So do you rate the design? :)
The resistors used in Alan’s photos are thick film and metal oxide types which were available from RS components back when the Lentek was manufactured.
Ok, so when modding the unit do you recommend that these resistors are retained? I'm only saying that if you think they are in some way key to how it sounds, or if they'd be better replaced with something better from currently produced options?
Marco.
Some respect due to Lentek over their choice of transistors (of those available then).
Interesting, Jez, so what are they exactly and why is respect due? Are these transistors still available now, or if not what would you suggest betters them? :)
The transistors were actually the last thing I was thinking of changing anyway, as I suspected that they were a big part of why the unit sounds like it does.
Tis' a pity that for reasons of battery life, size and price the collector current is so low as to make it so hissy...
So could that issue be successfully addressed?
Marco.
Incidentally, for anyone considering building a Lentek head amp for themselves, the 2SA1085 and 2SC2547 with a source impedance of 100R both have a noise factor (NF) of around 0.5 dB and they are effectively operating in parallel for noise purposes, so the averaged noise contribution would be less than 0.5 dB without a cartridge connected. The noise level would rise slightly with a low impedance cartridge connected but would still be acceptable. These transistors are not current production items but they can still be sourced from surplus outlets.
So, just to clarify, for us numpties, the 2SA1085 and 2SC2547, of which you speak, are the transistors used in the Lentek? :)
Do any of you guys have some spare ones, then? Would be useful to know in case any currently being used go tits up. One other thing I'd like to do is house the whole thing in a non-magnetic case. The stock one is ferrous and creates a significant magnetic field around the components, which in my experience is sonically suboptimal.
Marco.
think they are available here (https://www.reichelt.com/?LANGUAGE=EN&CTYPE=0&MWSTFREE=0&CCOUNTRY=447&ARTICLE=15473&PROVID=2788&wt_guka=22596778217_79177357817&PROVID=2788&gclid=Cj0KEQiApqTCBRC-977Hi9Ov8pkBEiQA5B_ipRrVwY8zgMDzakPKUyoWklpaUeP96l sBJdjhsqB-0toaArmk8P8HAQ)
Arkless Electronics
09-12-2016, 02:15
Interesting, Jez, so what are they exactly and why is respect due? Are these transistors still available now, or if not what would you suggest betters them? :)
The transistors were actually the last thing I was thinking of changing anyway, as I suspected that they were a big part of why the unit sounds like it does.
So could that issue be successfully addressed?
Marco.
They are no doubt available still with a bit of a search. To expound on my earlier post, transistors come in opposite polarities (and all audio EE's wish valves did!) and ideally in a push pull circuit we want them to be perfect mirror images of each other. This is normally done by using two transistors of the same series or family, which are intended to be complementary to each other. In the case of the Lentek they have gone above and beyond the call of duty and experimented with all sorts of transistors , but only those with at least some pretence of not hissing, to find ones that are more perfectly mirror images of each other than could be expected from choosing them from even those intended to be mirror imaged....
The 2SA1085 and 2SC2547 complementary pair (not even available when this was made and "obsolete", as in still fantastic but they don't make them any more, not as in that there are better more modern parts available. see my earlier post on this matter!), which Paul mentions are an interesting choice which, whilst I haven't done any analysis of it, I think see what he's probably getting at here...
They are not a fantastic choice for a MC head amp, not that bad either, (very good for a MM one though) but, bearing in mind how current starved the devices are in this application , they may well be a better compromise under these battery saving conditions than something ostensibly far more suitable for low noise with a source impedance as low as that of an MC cart. So probably a good shout but would need some measurements etc to confirm:)
To get to Marco's other point in the next post (i think) and take it further (:eyebrows:).. the ultimate Lentek? would put the PCB in a much bigger box and powered by a lantern battery (or similar capacity of rechargeable's), this would allow the current to be upped to reduce the hiss by probably at least half, and I would hope down to about 1/4 of original.. the extra class a, whilst technically pretty irrelevant, may smooth and refine it in practice....the tantalum capacitors would be replaced by polypropylenes FAR too big to go in the original box (similar to but bigger than the ones you used in the 15XR rebuild Marco). Not cheap to do other than as a labour of love of course!
As to, whilst probably making it a much better unit overall, would it keep whatever "je ne sais quoi" it's reputed to have....? Anyone's guess I'm afraid.. not predictable by any theory or measurement..( calm down Marco :D) it would need to be tried to find out but the above is about as far as one can go in taking a Lentek to the limit but not really changing that much of the original design.
Paul Hynes
09-12-2016, 12:02
Hi Marco,
Undoubtedly each of the components used in the Lentek circuit will have a sonic signature, but as Jez points out, changing components may upset the sonic balance and the only way to find out is to try changing components. Very time consuming, as some burn-in time should be allowed for each component for conclusive results.
I used the brown thick film resistors in many designs in the 1980s with good sonic results. I initially chose them because they were manufactured using non-magnetic materials and I preferred their sonic signature over the slightly grittier signature of the grey resistors, which, incidentally, had magnetic material in the end caps on the resistor body.
I also used the 2SC2547 and 2SA1085 in many designs. The 2SC2547 was used in an MC input phono stage and 8 were wired in parallel on each side of the input differential pair to reduce their overall noise contribution. This MC phono stage was astonishingly quiet and the low level information retrieval was exceptional. Unfortunately I have no idea how these transistors would compare sonically with the ones used in the Lentek.
Thanks for that, guys. It's all very useful info that I'll be bearing in mind for the future :thumbsup:
Marco.
Paul Hynes
10-12-2016, 20:11
I have been playing around with the circuit using ZTX651 and ZTX751 in my plug-in breadboard. With circuit values readjusted to work with an Aerospace 6v spiral wound lead acid gel battery that I use on my test bench, the circuit shows good linearity and low noise with a voltage gain of 24 with the readjusted circuit values. There were no stability problems shown on the oscilloscope and I would expect decent performance from the waveforms present during testing.
The 6v battery has way more charge available than a PP3 battery so I also set the circuit up for 2.5ma quiescent current in the transistors and the circuit works well providing a voltage gain of 33 due to lower resistor values from the transistor emitters to the battery terminals.
I would be interested to hear what the circuit can do in my system and may, if time allows, prepare a circuit board layout for inclusion on my next circuit board order, probably in Feb/March. This will allow me to experiment with different components without repeated modification of one board, which can eventually lead to board damage.
Sounds very interesting, Paul. Please keep us posted! :cool:
Marco.
Arkless Electronics
11-12-2016, 14:13
I have been playing around with the circuit using ZTX651 and ZTX751 in my plug-in breadboard. With circuit values readjusted to work with an Aerospace 6v spiral wound lead acid gel battery that I use on my test bench, the circuit shows good linearity and low noise with a voltage gain of 24 with the readjusted circuit values. There were no stability problems shown on the oscilloscope and I would expect decent performance from the waveforms present during testing.
The 6v battery has way more charge available than a PP3 battery so I also set the circuit up for 2.5ma quiescent current in the transistors and the circuit works well providing a voltage gain of 33 due to lower resistor values from the transistor emitters to the battery terminals.
I would be interested to hear what the circuit can do in my system and may, if time allows, prepare a circuit board layout for inclusion on my next circuit board order, probably in Feb/March. This will allow me to experiment with different components without repeated modification of one board, which can eventually lead to board damage.
I thought those ZTX's would do the trick ;)
I'll not be bothering with PCB's here.... If folks want a clone of it from me it will be on glass fibre veroboard or point to point wired on tag strip.
Paul Hynes
11-12-2016, 18:09
Hi Jez,
The ZTX’s maintain decent Hfe in the circuit with standard values with a quiescent current in the region of 250 microamps so they are a good choice for this circuit electrically. I have used these devices since they were first introduced because of their linear Hfe characteristics. I cannot comment on sound quality in the Lentek circuit until I have some listening time under my belt probably around springtime. Although if I get chance to sneak into the workshop over Xmas I may do a quick hardwire job for a first impression as the low component count makes this easy enough.
Incidentally Jez, I was not considering offering boards or modules using this circuit when I said I would get some boards made. This is purely to make life easy for component comparisons as a fun personal project in the spirit of the forum ethos and I am happy to disclose any interesting findings as the project progresses.
Arkless Electronics
12-12-2016, 15:47
Hi Jez,
The ZTX’s maintain decent Hfe in the circuit with standard values with a quiescent current in the region of 250 microamps so they are a good choice for this circuit electrically. I have used these devices since they were first introduced because of their linear Hfe characteristics. I cannot comment on sound quality in the Lentek circuit until I have some listening time under my belt probably around springtime. Although if I get chance to sneak into the workshop over Xmas I may do a quick hardwire job for a first impression as the low component count makes this easy enough.
Incidentally Jez, I was not considering offering boards or modules using this circuit when I said I would get some boards made. This is purely to make life easy for component comparisons as a fun personal project in the spirit of the forum ethos and I am happy to disclose any interesting findings as the project progresses.
Same here... useful devices for a wide range of applications.. I remember when they were Ferranti... and it were all trees round here you know :wheniwasaboy: :)
I have no issues if you had been planning to offer boards... the designs in the public domain :) My offer to do so earlier in the thread is merely me thinking maybe I can make a wee bit of money here and there from it if there is more demand for Lentek head amps than available ones.... If, as I suspect, people won't pay more for a new one than for a second hand one (nowt as queer as folk..) it will go nowhere...
I have my very low noise test gear on the bench ATM anyway as I'm building one of my FET head amps (up market one, not the budget one) for a customer, so I will probably knock up a Lentek this end as well... and knowing me it will end up a "souped up" one...
anthonyTD
13-12-2016, 12:55
I also chose Transistors from the ZTX range, to use in a low voltage, low noise, temperature compensating, voltage refrence, for the Soul series, good devices.:)
Good luck with the developement/testing Paul, Jez.
Hi Jez,
The ZTX’s maintain decent Hfe in the circuit with standard values with a quiescent current in the region of 250 microamps so they are a good choice for this circuit electrically. I have used these devices since they were first introduced because of their linear Hfe characteristics. I cannot comment on sound quality in the Lentek circuit until I have some listening time under my belt probably around springtime. Although if I get chance to sneak into the workshop over Xmas I may do a quick hardwire job for a first impression as the low component count makes this easy enough.
Incidentally Jez, I was not considering offering boards or modules using this circuit when I said I would get some boards made. This is purely to make life easy for component comparisons as a fun personal project in the spirit of the forum ethos and I am happy to disclose any interesting findings as the project progresses.
Wakefield Turntables
25-01-2017, 14:08
Any further development on this? I'm using my Lentek (Nick G modded) to very good effect, it's the new year so I fancy something trying something different.
Arkless Electronics
25-01-2017, 14:36
Any further development on this? I'm using my Lentek (Nick G modded) to very good effect, it's the new year so I fancy something trying something different.
I didn't get round to it and have been to busy with more important stuff TBH... I can't see me ever taking it further now the mental impetus has been lost. I doubt anyone would spend say £300 - £400 on a hugely souped up version of the Lentek anyway...
I would, if it was good! :)
Marco.
Wakefield Turntables
25-01-2017, 15:45
I didn't get round to it and have been to busy with more important stuff TBH... I can't see me ever taking it further now the mental impetus has been lost. I doubt anyone would spend say £300 - £400 on a hugely souped up version of the Lentek anyway...
why dont you tell us what you'd do to the Lentek and then lets US decide if we want to spend £3-400 of our money. You shouldn't make assumptions. ;)
Wakefield Turntables
29-01-2017, 20:08
I'm looking into getting mine further modded. Just looking at components and speaking to my favourite cable maker to see if something can be rustled up. What this space. :eek:
Arkless Electronics
30-01-2017, 12:56
why dont you tell us what you'd do to the Lentek and then lets US decide if we want to spend £3-400 of our money. You shouldn't make assumptions. ;)
No. That's not how I do things. Any customer with the technical knowledge to know how any mods I make will be likely to effect things could design it themselves anyway... Those without that knowledge are in no position to comment anyway...
What I was proposing was NOT to take in Lenteks and modify them but to build new "Lentek's" from scratch in a much bigger case, which would be required for the mods I had in mind.
I can make one's of my own design that are much better anyway. As recent reviews show.
Wakefield Turntables
30-01-2017, 13:02
No. That's not how I do things. Any customer with the technical knowledge to know how any mods I make will be likely to effect things could design it themselves anyway...
I can make one's of my own design that are much better anyway. As recent reviews show.
Probably not the best way to handle customers Jez in that some of use like an active role in design and parts selection. I'm sure you can a much better head amp but I've not heard it so can't judge, the Lentek is a known entity and therefore worthy of investment unlike yours which is something that I'd have to spend £700+ on before I even had chance to hear it. A single review dosen't make a product. Anyway I'm already on with this project. Good luck with your future sales.
Arkless Electronics
30-01-2017, 13:29
Probably not the best way to handle customers Jez in that some of use like an active role in design and parts selection. I'm sure you can a much better head amp but I've not heard it so can't judge, the Lentek is a known entity and therefore worthy of investment unlike yours which is something that I'd have to spend £700+ on before I even had chance to hear it. A single review dosen't make a product. Anyway I'm already on with this project. Good luck with your future sales.
Changes to the design are needed rather than mere parts selection. I will probably make an Arkless MkII head amp for my own use which can also go out for demo but it would be "cobbled together" in comparison to ones made for customers. This would not effect sound.
Wakefield Turntables
30-01-2017, 13:42
I have no issues with cobbled together. I remember trying your phonostage and writing a very positive review. You've certainly got the talent to produce these things but as I stated sometimes the fun, for the purchaser, is being part of the journey.
Arkless Electronics
30-01-2017, 14:24
I have no issues with cobbled together. I remember trying your phonostage and writing a very positive review. You've certainly got the talent to produce these things but as I stated sometimes the fun, for the purchaser, is being part of the journey.
As you very much were when I built that speed controller for you:) I encourage customers to have an input into what they receive but it stops short of the actual electronic engineering, ie the design, which for obvious commercial reasons I don't discuss in any detail on public forums. If customers want a particular brand of capacitor fitted etc then I'm fine with that... so long as it is a suitable choice technically of course.
Wakefield Turntables
30-01-2017, 20:19
As you very much were when I built that speed controller for you:) I encourage customers to have an input into what they receive but it stops short of the actual electronic engineering, ie the design, which for obvious commercial reasons I don't discuss in any detail on public forums. If customers want a particular brand of capacitor fitted etc then I'm fine with that... so long as it is a suitable choice technically of course.
Fair point old bean. ;)
Wakefield Turntables
30-01-2017, 20:22
Just out of interest, does anyone have any idea how gain the Lentek generates?
Wakefield Turntables
30-01-2017, 20:24
ok, its 28db!
Wakefield Turntables
31-01-2017, 19:41
ok, looks like a have a few components as contenders for my Lentek modifications, so a few basic specs
1. Charcroft audio silver mica capicators
2. Yannis tome 222 IC
3. WBT-0110Ag Signature RCA's
4. wbt-0210ag topline RCA sockets
5. Charcroft z or S seris resistors
6. Maybe a new case.
I want to try and increase gain if possible with resistor value tweaks. Looks like it's going to stay battery powered as I dont really want a complete redesign of the whole head amp to get a very noise free, floating power supply. Apart from that it looks like a fairly standard refurb of the innards with better quality componets.
just to revive this great thread,
i now have 2 lenteks,one standard 'as they come' and one to mod.
this evening i set about removing all the potting,the pcb is incased in a block of white silicone,after an hour of picking and cutting its all gone.
pic 1 is the what we see when the plastic cover is cut off.
https://s26.postimg.org/ledwba4mx/IMG_1919_1.jpg
an hour later.....
https://s26.postimg.org/w17pgysah/IMG_1921_1.jpg
and here's a pick for people with more knowledge than me of the pcb and tracks going to the components.
https://s26.postimg.org/4dv02meqx/IMG_1923_1.jpg
so my plan is to replace the caps with high quality ones 1 at a time and compare against the standard one,also on the cards is making a bigger box for it and replace the rca connectors and cable/plugs.
any advice on components/values etc is more than welcome :)
Pic of the underside
https://c2.staticflickr.com/6/5572/30629702713_c0d39748cc_b.jpg (https://flic.kr/p/NEDeuD)IMG_2683 (https://flic.kr/p/NEDeuD) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
just reading through this thread and i noticed there appears to be at least 3 versions on the lentek,in the alans post above the second picture shows a mk3 pcb,mine has mk2 printed on it,
https://s26.postimg.org/n0glj9u61/IMG_1924_1.jpg
Pic of the underside
https://c2.staticflickr.com/6/5572/30629702713_c0d39748cc_b.jpg (https://flic.kr/p/NEDeuD)IMG_2683 (https://flic.kr/p/NEDeuD) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr
Alan
just reading through this thread and i noticed there appears to be at least 3 versions on the lentek,in the alans post above the second picture shows a mk3 pcb,mine has mk2 printed on it,
https://s26.postimg.org/xaj0iozix/IMG_1924.jpg
Wakefield Turntables
28-01-2018, 10:37
would it help if I posted a picture of mine with the mods?
walpurgis
28-01-2018, 10:43
just reading through this thread and i noticed there appears to be at least 3 versions on the lentek,in the alans post above the second picture shows a mk3 pcb,mine has mk2 printed on it
It's possible version 1 was a development board that was never put into production.
yep maybe,it would seem from comparing the 2 pcbs thats my transistors are different,the ones in the mk3 are BD380 transistors where as mine are in metal cans,i have 2 marked BF X85 and 2 marked BC461 87742.
what the difference is and if ones better than another is over my head.
im getting a bit confused with regards to replacing these capacitors,nf,pf or uf??
i need 2 of these,
https://s26.postimg.org/w418eaoyx/IMG_1935_1.jpg
and 3 of these,
https://s26.postimg.org/3r5qnuqe1/IMG_1936_1.jpg
Firebottle
29-01-2018, 08:04
The top two are 220pF (0.22nF). The bottom one is 10nF. :)
Thanks Alan , I had a good read up on cap markings last night and sussed it in the end:)
ive been using a denon ha-500 headamp so the poor little lentek hasn't had a look in,today i recapped it though which is a start :)
does anyone know if the wilmas are bipolar?
https://s26.postimg.org/t86f09qs9/IMG_1997_1.jpg
Firebottle
25-02-2018, 22:11
The Wimas are none polarised.
Best type of capacitor to stick in there is either polystyrene or polypropylene dielectric.
However you only need a low voltage rating of capacitor, the problem will be finding small ones as most of this type of capacitor have large voltage ratings and will be correspondingly large in size.
Good luck :)
PS may be best to try it as is and see what the improvement is so far.
Cheers Alan,yep that’s the plan for next weekend
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