View Full Version : Has anyone tried this Passive Pre?
Found on eBay: http://bit.ly/1qmaZ0X
Or website: http://www.khozmo.com
They look beautifully made.
istari_knight
08-04-2014, 20:33
Nope, sorry.
I have been ogling them for a couple of years now though since the seller first showed them off on diyaudio... Certainly look nicely made.
Funny, I was looking at that site today too - prompted by the thread in the Drawing Room forum about their stepped attenuator.
Held off asking the very same question.. The remote controlled versions look good.
I'd like a balanced version but balanced attenuation can be done with a shunt circuit effectively adjusting an amount of summing of the two out of phase signals and so therefore only using a dual pot/attenuator rather than the quad as is usually sold for balanced. It's what Audio Synthesis did for their ProPassion balanced attenuators as it prevents mis-matching of the dual attenuators on each channel from effecting the balanced topology.
killie99
09-04-2014, 08:06
'Rune' on PinkFish has one, rates it very highly, as does John Westlake (Mr MDAC)
Funny, I was looking at that site today too - prompted by the thread in the Drawing Room forum about their stepped attenuator.
Indeed - Joe was rather impressed with it, and I'm due to visit him on Sunday. That passive pre has a look of 'rightness' about it, although I'd want the Vishay Z-foil series resistors fitted. I'm almost tempted to blow next month's wine budget on one, just to see what it would do in my system, in comparison with the Croft...
If it doesn't work out, I could rob the stepped attenuator from it, compare that with the DACT unit I'm currently using in the Croft, and keep the rather nice case for some other project (perhaps to house some vintage transformers inside a bespoke-built SUT)? :hmm:
Marco.
john dolan
09-04-2014, 10:27
Good review here
http://www.6moons.com/audioreviews/khozmo/1.html
Can buy just the attenuator here
http://www.hificollective.co.uk/catalog/newsdesk_info.php?newsdesk_id=189"
Looks very nicely made and extremely well priced. However, at the end of the day it is still a standard passive pre - personally, I would be more tempted by something like this:
http://www.hificollective.co.uk/images/gh_chassis_blkm.jpg
a TVC passive - a Glasshouse one in this case.
john dolan
09-04-2014, 10:48
Looks very nicely made and extremely well priced. However, at the end of the day it is still a standard passive pre - personally, I would be more tempted by something like this:
http://www.hificollective.co.uk/images/gh_chassis_blkm.jpg
a TVC passive - a Glasshouse one in this case.
Heres mine
http://i57.tinypic.com/16i6u0o.png
john dolan
09-04-2014, 10:54
I find the TVC has a little more weight and punch over a normal passive preamp but they don't have it all their own way.
A normal passive in a system that's sympathetic to a passive has greater clarity and seems more honest to the signal to my ears.
A TVC will work in systems where a normal passive wont give its best.
Here is my Glasshouse passive with Seiden 43 step attenuator
http://i61.tinypic.com/p3xiu.jpg
john dolan
09-04-2014, 10:57
Marco you could just do a Zfoil shunt mod to your DACT
http://www.world-designs.co.uk/forum/showthread.php?t=5795
Here is a pic of the one on my DACT
http://i61.tinypic.com/el6zr7.jpg
Looks very nicely made and extremely well priced. However, at the end of the day it is still a standard passive pre - personally, I would be more tempted by something like this:
http://www.hificollective.co.uk/images/gh_chassis_blkm.jpg
a TVC passive - a Glasshouse one in this case.
How much is that one, Mark? If I was to pull the trigger on a passive pre, I'd only want to speculate at the most with £300, and of course part of that exercise would be to hear how good the Khozmo stepped attenuator itself was...
Plus, I much prefer the looks of the Khozmo passive to the TVC/Glasshouse unit! :)
Marco.
anthonyTD
09-04-2014, 11:01
They are a very good passive preamp, WELL MADE,and a steal at the price, also,The guy that makes them is real nice, and great to deal with, they use the same Attenuators that Joe has just purchased and started a thread about, i use one of their Attenuators in my own preamp at the moment, they do a shunt, or series type.:)
Found on eBay: http://bit.ly/1qmaZ0X
Or website: http://www.khozmo.com
They look beautifully made.
john dolan
09-04-2014, 11:11
Marco the Glasshouse TVC well mine was about £600 as a kit which is not a easy build.
The Glasshouse normal passive is here £180 without attenuator
http://www.hificollective.co.uk/catalog/glasshouse-passive-preamplifier-without-attenuator-p-9624.html
They sell a large range to pick from cheap Alps to the Seidon I used which cost near £600.
They also sell the Khozmo passives
http://www.hificollective.co.uk/catalog/khozmo-passive-preamp-with-stepped-attenuator-step-p-9547.html
Marco you could just do a Zfoil shunt mod to your DACT
http://www.world-designs.co.uk/forum/showthread.php?t=5795
Here is a pic of the one on my DACT
http://i61.tinypic.com/el6zr7.jpg
Interesting, and I may consider it. However, my one and only experience with shunted units (Glasshouse Takman) wasn't terribly good, as the shunting reduces gain, does it not (?) and on my preamp that made for a somewhat soft, 'padded' sound, in comparison with the brutal 'take no prisoners' open-window resolution of the (un-shunted) DACT, which I love.
I'm always open to interesting suggestions, however, and I don't mind trying the shunt option with a passive preamp :)
Marco.
john dolan
09-04-2014, 11:18
Marco depends on the resistor value if the gain changes or not.
The Zfoils are the best sounding resistors ive used and improve the DACT.
In my passive I used 10k the same value as the DACT so gain is unchanged but the one in my Tom Evans preamp I changed the values to 17 k to lower the gain as the volume was too hot.
The DACT is very good its just the lack of steps that made me spend silly money on the Seidon which does sound better than the DACT imo.
john dolan
09-04-2014, 11:20
I changed the 2 Vishay that fit across the RCA to Zfoils inside my AS Passion.
Its worth changing the DACT for the Khozmo attenuator just for the extra steps.
If you got a bit of DIY skill or know someone with those skills I really recommend the Slagle Volume Controller
http://www.enjoythemusic.com/diy/0611/slagle_autoformer_volume_control_modules.htm
http://www.intactaudio.com/atten.html
Marco depends on the resistor value if the gain changes or not.
The Zfoils are the best sounding resistors ive used and improve the DACT.
In my passive I used 10k the same value as the DACT so gain is unchanged but the one in my Tom Evans preamp I changed the values to 17 k to lower the gain as the volume was too hot.
The DACT is very good its just the lack of steps that made me spend silly money on the Seidon which does sound better than the DACT imo.
Interesting, John. Noted on the gain thing.
I mistakenly thought that gain reduction was an automatic by-product of shunting. I'm still learning in this area! :)
When you say the 'Seidon' is better than the DACT, do you mean this unit, available from HFC (shown on the left): http://www.hificollective.co.uk/images/takman_metal_swl.jpg described on the website as a 'Glasshouse Takman'. I'm sure that's a Seiden.
I had the metal-film version of that and, in my preamp and system, it was considerably outperformed by the DACT. However, if the DACT can be upgraded with Z-foil resistors, then that would be very interesting!
Marco.
john dolan
09-04-2014, 11:52
This one
http://www.hificollective.co.uk/images/seidenatt3l.jpg
http://www.hificollective.co.uk/pdf/seiden_attenuator.pdf
Heres mine
http://i61.tinypic.com/hu1yiw.jpg
That attenuator cost near £600 Marco and its very large so needs a box like the Glasshouse to fit.
Ah - gotcha! I haven't tried that one. Space isn't an issue inside my preamp. Interesting... I guess it all depends on what would end up sounding better: one of those boys you've got, a Z-foil modified DACT, or a Z-foil Khozmo? :hmm:
Marco.
john dolan
09-04-2014, 12:06
Marco the quality of the switch and the resistors does make a difference and they sound different to eachother even when they all use the same Zfoil.
This is my fav and what I use atm
http://i62.tinypic.com/347jtrk.png
That's the internal pic of my AS Passion the 2 Vishay resistors on the RCA ive changed for Zfoils.
The DACT with Zfoils sounds different to the Seidon which again sounds different to the Passion.
Cool... How would you describe the difference between the DACT with Z-foils, and the Seiden with Z-foils? :)
My aim is always to achieve maximum resolution: I want to hear every possible detail in the music with no artificial warmth, masking or rounding-off/bloating at the frequency extremes.
An attenuator that sounds of 'nothing' would be ideal!
Marco.
Marco, I'm not sure if your intention is to investigate passive pre-amps or just volume controls? However, I certainly wouldn't seek to draw any conclusions about a volume control when used in a passive - the nature of how a passive pre integrates with the source output and the power amps input is likely to have a far more dominant effect than the volume control itself.
I'm not saying the volume control doesn't make a difference, but you can't use a passive to evaluate how they will perform in an active pre.
The mention of Z-foils is interesting because none of those shown actually use them for the switch resistors - to do that would be mighty spendy.
john dolan
09-04-2014, 13:43
The DACT has very clear sound with good detail which the Seidon also has but the Seidon has fuller tone with richer textures.
Its like going from a good SS amp to a Good valve amp if you know what I mean.
The Passion passive is the nearest thing to nothing in the signal path ive heard and sounds bang in the middle between DACT and Seidon.
Ive got a M-dac which I use to test my preamps with.
I listen to high res file with with headphones into the M-dac then the M-dac direct to my power amps then M-dac through the passives.
The DACT is mighty close but the other 2 closer still to adding nothing of their own character but bear in mind they are much more expensive switches than the DACT.
The Seiden 2 pole 43 way switch without resistors alone cost £225 and mine made up was near £600 so the DACT is mighty for what it costs and I was happy with the sound it was only the lack of steps I wasn't keen on.
With the Seidon I bought it with carbon resistors but I experimented with Audio Note and Shinkoh Tantalum Resistors but for me the Charcroft Z-Foil Resistors sound the best to my ears.
Thanks for that, John.
The DACT has very clear sound with good detail which the Seidon also has but the Seidon has fuller tone with richer textures.
Its like going from a good SS amp to a Good valve amp if you know what I mean.
Lol... I guess that I do and I don't. The problem is how one perceives the sound of a valve amp is rather subjective. My amps are not typical valve amps, in terms of sonic signature. The "fuller tone" thing worries me a little, as that suggests a deviation from neutrality and/or a 'warmer' sound, which is defintely not something I would want. However, I think I know what you're getting at.
The last Seiden-based Takman attenuator I used also had a fuller tone than the DACT, and when the latter produced a tighter sound with greater clarity, it was a definite bonus and a move more in keeping with the type of sound I like, so if going for the same Seiden unit as you results in the return to a fuller tone, then I wouldn't want that - and it's a sizeable amount of dosh to waste if I didn't like the sound...
It not easy to try and work these things out, lol!
Therefore, I'm leaning more now towards trying some Z-foils in the DACT attenuator I'm using now, as I'll be able to determine instantly whether I like the effect or not. The DACT I have is a 100K unit, so which resistors/values would I need to get, in order to upgrade the stock resistors fitted?
Marco.
Hi Mark,
Marco, I'm not sure if your intention is to investigate passive pre-amps or just volume controls? However, I certainly wouldn't seek to draw any conclusions about a volume control when used in a passive - the nature of how a passive pre integrates with the source output and the power amps input is likely to have a far more dominant effect than the volume control itself.
I'm not saying the volume control doesn't make a difference, but you can't use a passive to evaluate how they will perform in an active pre.
The mention of Z-foils is interesting because none of those shown actually use them for the switch resistors - to do that would be mighty spendy.
I'm not really that bothered about trying a passive preamp, but for £300 (or so), with Z-foils fitted, the Khozmo passive pre looked interesting and is cheap enough to 'speculate to accumulate' with.
Other than that, the main point of the exercise was to experiment with stepped attenuators and see whether my current DACT unit could be improved upon, either by upgrading the stock resistors for Z-foils or replacing it with a Khozmo stepped attenuator, fitted with Z-foils.
Aside from purely sonics, I could do with having more steps on my volume control, as the DACT is a little limited in that respect. Therefore, as ever, I'm open to suggestions! :)
Marco.
Well I see that Khozmo Z-foil option is only $60 more so they won't be changing many of them (2 I suspect).
john dolan
09-04-2014, 16:46
Thanks for that, John.
Lol... I guess that I do and I don't. The problem is how one perceives the sound of a valve amp is rather subjective. My amps are not typical valve amps, in terms of sonic signature. The "fuller tone" thing worries me a little, as that suggests a deviation from neutrality and/or a 'warmer' sound, which is defintely not something I would want. However, I think I know what you're getting at.
The last Seiden-based Takman attenuator I used also had a fuller tone than the DACT, and when the latter produced a tighter sound with greater clarity, it was a definite bonus and a move more in keeping with the type of sound I like, so if going for the same Seiden unit as you results in the return to a fuller tone, then I wouldn't want that - and it's a sizeable amount of dosh to waste if I didn't like the sound...
It not easy to try and work these things out, lol!
Therefore, I'm leaning more now towards trying some Z-foils in the DACT attenuator I'm using now, as I'll be able to determine instantly whether I like the effect or not. The DACT I have is a 100K unit, so which resistors/values would I need to get, in order to upgrade the stock resistors fitted?
Marco.
You need to do the shunt mod on the DACT
http://www.world-designs.co.uk/forum/showthread.php?t=5795
Use 2 of these
http://www.hificollective.co.uk/catalog/car490-100k-charcroft-zfoil-resistor-p-5078.html
Hi John,
Thanks for that and the rest of your help so far :)
I'll keep hold of the info and pass it onto whichever one of my techy friends who'll be doing the job, if I go for it. At the moment, I'm seriously toying with the idea of going for one of the Z-foil modified Khozmo passives, just to see what that brings to the party, and if it doesn't work out, simply fit the stepped attenuator into my Croft preamp :cool:
Marco.
Well I see that Khozmo Z-foil option is only $60 more so they won't be changing many of them (2 I suspect).
Indeed. However, there's nothing to stop more being changed later, and going to town on the switch resistors, is there...? ;)
Marco.
Well, the z-foils aren't a very standard resistor shape and they aren't available in every value...
Lol... What are you like? I'll change as many of them as can be changed, then! :eyebrows:
Anyway, I think the first move will be to try one of the Z-foil upgraded Khozmo passive preamps, and take it from there :)
Marco.
http://www.khozmo.com/images/zfoil_24.jpg
They show that image but don't give a price... the only price shown is for the Z-Foil in a shunt position.
.. and appears to be a 24 position unit (unless there are some more further in).
Marco the quality of the switch and the resistors does make a difference and they sound different to eachother even when they all use the same Zfoil.
This is my fav and what I use atm
http://i62.tinypic.com/347jtrk.png
That's the internal pic of my AS Passion the 2 Vishay resistors on the RCA ive changed for Zfoils.
The DACT with Zfoils sounds different to the Seidon which again sounds different to the Passion.
WHat are the shunt resistors used on the Passion? Nice thing about the Passion is the spring loaded notched thing at the front. They do go for what I consider daft prices secondhand.. must be good in comparison to new stuff. A couple of single input, mono units fetched near £400 on ebay this week.
The Black Adder
09-04-2014, 21:29
That will be megabux... Looks ace though.
I'm very happy with my Khozy. Sound wise it's the most accurate realism I've heard and the ZFoils are digging in nicely now, it just keep on improving.
For those who have not read this.. http://theartofsound.net/forum/showthread.php?31816-The-Khozomo-Mkii-Stepped-attenuator
Ta
I've used z-foils for cartridge loading a couple of times now and do think they make a worthwhile difference.
That will be megabux... Looks ace though.
I'm very happy with my Khozy. Sound wise it's the most accurate realism I've heard and the ZFoils are digging in nicely now, it just keep on improving.
For those who have not read this.. http://theartofsound.net/forum/showthread.php?31816-The-Khozomo-Mkii-Stepped-attenuator
Ta
Good to hear..
Apparently the Z-Foils are about $10 each direct: http://www.texascomponents.com/store/VishayFoilResistors.asp and they make ANY value you want with no miminum order!
Possible perhaps to upgrade a Dale version at a later date.. for only $960 + postage! haha..
anthonyTD
10-04-2014, 09:14
hi Marco,
You know i have never been a personal fan of passive pre-amps, mainly because they can lack drive, and therefore immediacy in some systems,so, i would advise you to think carefully about going from your croft [which we both know its sonic qualities very well] to an all passive type, however, if your after more steps/adjustment over the volume range, then the Khozmo attenuator is a good alternative, however, as i stated in Joe's thread, there is a sonic diffrence between the DACT and the Khozmo types,so again, it would be down to a bit of trial and error.
Lol... What are you like? I'll change as many of them as can be changed, then! :eyebrows:
Anyway, I think the first move will be to try one of the Z-foil upgraded Khozmo passive preamps, and take it from there :)
Marco.
Hi Anthony,
Yup - we're on the same page, mate.
My thinking was simply that for around £300 (with the Z-foils fitted to the supplied attenuator), the Khozmo passive would be an interesting listen, compared with my Croft. Just a bit of fun, really! I have no intention for any passive preamp to replace it, but it could act as a handy back-up, should the Croft ever develop a fault, or need to go away for any modifications :)
Either that, and if I don't like how the passive preamp performs in my system, I'll simply remove the Khozmo stepped attenuator from it and try it in the Croft, and then use the casing to house some vintage MC transformers for a bespoke SUT. Therefore, nothing will get wasted!
Btw, could you have a look at the link to the thread on the World Designs forum John Dolan supplied in post #28, outlining the shunt mod for the DACT, including what would be involved in fitting the required Z-foil resistors, and confirm that you both understand how to do the mods and that it will not result in a reduction of gain on my preamp?
If it's a go-er, I'll buy the bits and bring the preamp down to have the mods carried out.
Cheers, dude! :cool:
Marco.
john dolan
10-04-2014, 09:40
nat8808
Mine is all Vishay but as I changed the 2 Vishay on the RCA for Zfoils.
I was bidding on that Pro Passion but set my limit at £350 as I already have my Passion which I paid £450 for about 6 months ago which is a lot for a 20 year old passive but its what they fetch and I wanted one.
I first heard one at a Nottingham HIFI show in Matlock in 94 and held one in my hand and lusted after one ever since.
Here is a review of the model before my all Vishay version to give you some idea how good they are.
http://www.audiosynthesis.co.uk/reviews/pasion_1hfn493.pdf
Martin Colloms used the all Vishay version as his reference when reviewing all other preamps for 20 years.
Edit found the all Vishay review
http://www.audiosynthesis.co.uk/reviews/passionhfn1194.pdf
just thought I would point out for anyone interestd in a high quality passive pre that there is an NVA P90SA for sale at £400 *elsewhere*. This is the same passive as I use and it does not lack drive as some passives do - I like rock, funk, rap etc I could not live with any lack of drive or impact for 1 second - well worth it as a new one is north of £700 now I think. To get an active pre with the same level of transparancy you would be talking several grand minimum.
I've no connection with the seller.
john dolan
10-04-2014, 11:56
yes Macca I own 12 preamps or so 6 passive 6 active give or take also TVC and valve preamps and passive preamps don't lack drive or bass when used in a system passive friendly.
They can sound thin and flat and boring if you get it wrong though but get it right passive is my preferred way.
Its the KISS method.
Im using the direct in input on my Passion which bypasses the selector switch the whole sound is going through 1 single Zfoil resistor per channel.
John - yes, would have to be some really special active pre-amp to tempt me away from the passive now. I also bypass the selector switch and it is like listening to the recording straight from the mixing desk.
This is the best pot I have come across: http://www.ebay.co.uk/itm/Alps-Japan-Super-High-end-Potentiometer-Rk50112-Logarithmic-Log-Rk50-/261397002577?pt=UK_BOI_Electrical_Components_Suppl ies_ET&var=&hash=item3cdc79b951
The thing about this pot is it will last a very, very long time. Most stepped types the contacts wear. Unfortunate, but very, very true. The price is good - I've not seen them new that cheap before. I've seen it used in Kondo M7s.
If I went back to using my Air Tight passive, which has one of those in it with remote control, I'd change the DAC output in my Lampizator to be 4V. The perennial problem with passives is not enough gain.
Raised this thread a while ago: http://theartofsound.net/forum/showthread.php?25520-Khozmo-Passive-Preamps-Cheap-AND-Lovely!/page2
Of course that isn't to say the Khozmo won't last a very reasonable amount of time, especially considering the cost;)
anthonyTD
10-04-2014, 15:00
There are plenty of good sounding pots in boxes around, however, the main reason i went over to Stepped Attenuators was the accuracy aspect, conventional stereo carbon pots can have quite poor accuracy across their full travel, and can therefore affect the output level of each channel at different position, when you design accurate circuitry, you want the benefits carried through the whole preamp, otherwise, whats the point in designing two identical channels with identical gain structures to maximize accurate sound-stage, and placement of instruments in live recordings only to mess it up at the attenuator!
A.
The Black Adder
10-04-2014, 15:02
This is the best pot I have come across: http://www.ebay.co.uk/itm/Alps-Japan-Super-High-end-Potentiometer-Rk50112-Logarithmic-Log-Rk50-/261397002577?pt=UK_BOI_Electrical_Components_Suppl ies_ET&var=&hash=item3cdc79b951
The thing about this pot is it will last a very, very long time. Most stepped types the contacts wear. Unfortunate, but very, very true. The price is good - I've not seen them new that cheap before. I've seen it used in Kondo M7s.
If I went back to using my Air Tight passive, which has one of those in it with remote control, I'd change the DAC output in my Lampizator to be 4V. The perennial problem with passives is not enough gain.
Raised this thread a while ago: http://theartofsound.net/forum/showthread.php?25520-Khozmo-Passive-Preamps-Cheap-AND-Lovely!/page2
Some shunt attenuators can also pop if the input voltage is over 3v too... Something to consider.
There are plenty of good sounding pots in boxes around, however, the main reason i went over to Stepped Attenuators was the accuracy aspect, conventional stereo carbon pots can have quite poor accuracy across their full travel, and can therefore affect the output level of each channel at different position, when you design accurate circuitry, you want the benefits carried through the whole preamp, otherwise, whats the point in designing two identical channels with identical gain structures to maximize accurate sound-stage, and placement of instruments in live recordings only to mess it up at the attenuator!
Indeed... Nice chatting earlier (as usual), mate. Plan now sorted, as discussed. Hope you're feeling a bit better now, too! :)
Marco.
There are plenty of good sounding pots in boxes around, however, the main reason i went over to Stepped Attenuators was the accuracy aspect, conventional stereo carbon pots can have quite poor accuracy across their full travel, and can therefore affect the output level of each channel at different position, when you design accurate circuitry, you want the benefits carried through the whole preamp, otherwise, whats the point in designing two identical channels with identical gain structures to maximize accurate sound-stage, and placement of instruments in live recordings only to mess it up at the attenuator!
A.
Fair point but I don't think you'll find that applies to an RK50.
The cheaper Alps pots can get noisy wipers after a few years and you can't get in there easily with switch cleaner. Well I couldn't.
You can win everything - tis all compromise - just pick yer poison:)
anthonyTD
11-04-2014, 09:47
I would also like to add that i prefer to use stepped attenuators between two dedicated gain stages, and therefore' not relying on the drive capability of the source equipment' and cable combination to drive the attenuator' [like a lot of pre-amps do] there are many advantages to this method.
A...
Is that gain stages or buffer stages (unless they're the same thing?). Have heard of people loving their DIY buffer -> attenuator -> buffer on places like diyaudio.com
anthonyTD
11-04-2014, 12:04
Hi Nat,
The stages i use have some gain,[not much, and i don't like conventional buffer stages with 100% feedback] but more importantly,they have real current drive capability, so it doesn't matter what position the volume attenuator is set at,;there is always more than adequate drive for a true portrayal of the source signal.
Is that gain stages or buffer stages (unless they're the same thing?). Have heard of people loving their DIY buffer -> attenuator -> buffer on places like diyaudio.com
Figlet108
14-04-2014, 21:52
just thought I would point out for anyone interestd in a high quality passive pre that there is an NVA P90SA for sale at £400 *elsewhere*. This is the same passive as I use and it does not lack drive as some passives do - I like rock, funk, rap etc I could not live with any lack of drive or impact for 1 second - well worth it as a new one is north of £700 now I think. To get an active pre with the same level of transparancy you would be talking several grand minimum.
I've no connection with the seller.
I used to have a P90SA too. Here are some photos of the insides:
https://lh3.googleusercontent.com/-ZUbmvPoHBwY/U0xVWAFlBbI/AAAAAAAACRw/60S2Rl57ojg/w849-h566-no/2014-04-13+12.37.29_resize.jpg
https://lh5.googleusercontent.com/-XlCXHwqrUh8/U0xVVvjJtvI/AAAAAAAACRw/JRD-sMvvIDg/w849-h566-no/2014-04-13+12.38.40_resize.jpg
https://lh4.googleusercontent.com/-RbHes6g5bls/U0xVYblFnUI/AAAAAAAACR0/KyShQZhYtHk/w849-h566-no/2014-04-13+12.40.44_resize.jpg
I believe the attenuators are just bought in ready assembled from hificollective or somewhere similar:
http://www.hificollective.co.uk/catalog/glasshouse-shinkohelma-stepped-attenuator-mono-p-2179.html
I put a system together for a friend and got them this passive instead:
http://www.ebay.com/itm/Passive-Preamplifier-Dale-Resistor-Stepped-attenuator-/271214681553?pt=US_Home_Audio_Amplifiers_Preamps&hash=item3f25a79dd1
Compared to the P90 there honestly wasn't a whole lot of difference between them to my or my friend's ears...
Hi Jason,
How are you, matey? Hope you are well :)
Correct me if I'm wrong, but is that the oft-mentioned 'pot in a box', sold for something like £700? Or if not, how much does the P90SA retail for? There's certainly not much in there for yer hard-earned...
Furthermore, if one compares the build quality of the P90SA against that of the Khosmo, which cost under £200, the 'SPPV' of the former doesn't appear to be too high:
http://imagizer.imageshack.us/v2/xq90/845/nsaj.jpg
http://imagizer.imageshack.us/v2/xq90/842/67qk.jpg
https://lh3.googleusercontent.com/-ZUbmvPoHBwY/U0xVWAFlBbI/AAAAAAAACRw/60S2Rl57ojg/w849-h566-no/2014-04-13+12.37.29_resize.jpg
Marco.
Incidentally, as NVA equipment has been brought into this discussion, but not the designer himself or his forum, I'd just like to reiterate our policy in that respect, and that overall on the RD/HFS discussing ban:
It should be noted that the above ban does not include sales/wants ads by members for NVA products in Private Exhibitions or standard queries/discussion about NVA products and services in any other area of the forum.
For example, if someone wants to advertise their NVA amplifiers or cables for sale, or post queries about NVA products and services in other areas of the forum, or discuss their NVA equipment, then this will be permitted, provided that no mention of Richard Dunn is made, out with of him simply being the owner of NVA and the designer of the company's products.
Please note, in particular, the parts highlighted in blue, which is what's happening here. Therefore, no rules are being broken, just in case anyone mistakenly thinks differently!
Marco.
The Grand Wazoo
14-04-2014, 23:10
.....the 'SPPV' of the former doesn't appear to be too high...
Can you actually see the SPP in that image? Where is it, wassit look like?
Lol... As ever in audio, one would have to listen to both products to ascertain that. However, I don't know about you, but if I didn't know which unit cost £195 and which one cost (£700?) I'd say that the Khosmo occupied the place of the latter, not the former.
The P90SA looks distinctly 'home-made' in comparison. However, that's only my opinion. If it outperformed the Khozmo, sonically, then I guess one would have to judge if the extra £500 was warranted or not.
It would be an interesting one to test. Perhaps if I buy the Khosmo, I could bring it to Macca's forthcoming bake-off and compare it to his P90SA in the same test system? To make it fair, a partnering NVA power amp (to ensure synergy with the P90SA), and a non-NVA power amp, could be used for the comparison. Then we'd soon know which passive preamp offered the highest SPPV :)
Marco.
The Grand Wazoo
14-04-2014, 23:35
I think Jason may have suddenly landed here to stir the effluent with his post.....
But anyway:
To try to bring a little balance to the discussion (albeit with dual-mono controls!) I've just had a look at the spec of that unit on the Ebay advert and, having bought a few Shinkoh resistors in the past (for my SUT), I can confirm that they are bloody expensive, so I don't expect the thing is priced stupidly. Whether it sounds better, I don't know but when I tried several different brands, the Shinkoh ones were clearly better.
To try to bring a little balance to the discussion (albeit with dual-mono controls!) I've just had a look at the spec of that unit on the Ebay advert and, having bought a few Shinkoh resistors in the past (for my SUT), I can confirm that they are bloody expensive, so I don't expect the thing is priced stupidly. Whether it sounds better, I don't know but when I tried several different brands, the Shinkoh ones were clearly better.
:D
Fair point, muchacho. When I made the comment I had no idea how much the Shinkoh tantalum resistors or Elma switch were - I was simply going on perceived material value, judging by the look of both products in and out.
You have to admit that the Khozmo unit looks far better made, and is outstanding value for money, given that £100 (or so) represents the cost of the stepped attenuator itself, if ordered separately, leaving a mere £95 to cover the cost of the superbly finished wooden casing and gorgeously chunky brushed aluminium fascia, high-quality control knobs (far nicer than those used on the P90SA), phono sockets and labour!! ;)
As for which one sounds best, well since Macca uses the NVA, I guess there's only one way to find out....
Marco.
Incidentally, as NVA equipment has been brought into this discussion, but not the designer himself or his forum, I'd just like to reiterate our policy in that respect, and that overall on the RD/HFS discussing ban:
Please note, in particular, the parts highlighted in blue, which is what's happening here. Therefore, no rules are being broken, just in case anyone mistakenly thinks differently!
Marco.
Well they weren't being breached.. until you discussed Voldermort in the context of the ban and not in the course of converstaion about him simply being the owner of NVA. You breached the ban Marco!!
You're banned for a week! Or in other words take the week off and leave the other mods to hold the fort for a bit..
Should have replaced the name with Voldermort as I have done .. and no-one will have had a clue what you were talking about.
(you need to add a clause which also allows his mention in the course of policing the ban)
Normally DIY trumps in the passive attenuator world but when you get something like the Khozmo made in an industrial heartland like Poland (that phrase probably doesn't make sense - I mean industry is readily there to make your parts for pretty cheap) then it gets to the price point where ready-made products hold the advantage.
Would be nice if they made something with a wider footprint, just for my personal aesthetic taste.
The Grand Wazoo
15-04-2014, 06:54
You have to admit that the Khozmo unit looks far better made...........the superbly finished wooden casing and gorgeously chunky brushed aluminium fascia, high-quality control knobs.....
A matter of opinion but I rather disagree. The design has potential, yes, but the detail is poor. I don't think that the wood is well finished at all and the quality of the knurling on the knobs looks like a proper arse-biscuit!
Lol - well, in this respect, we'll have to agree to disagree :)
It's certainly superbly finished, given that the complete preamp is produced, with the inclusion of a very high-quality stepped attenuator (one which I've now heard in a preamp near-identical to mine and am going to buy), for a mere £195 - that bit is indisputable!!
Marco.
Well they weren't being breached.. until you discussed Voldermort in the context of the ban and not in the course of converstaion about him simply being the owner of NVA. You breached the ban Marco!!
You're banned for a week! Or in other words take the week off and leave the other mods to hold the fort for a bit..
Should have replaced the name with Voldermort as I have done .. and no-one will have had a clue what you were talking about.
(you need to add a clause which also allows his mention in the course of policing the ban)
:lolsign:
Yeah, noted (although that should be taken for granted)!
Marco.
Cor, that really would be a novelty - a forum owner banning HIMSELF :rfl:
All very interesting...
I bought my P90 of a member here for £90 delivered. It had a damaged case (top plate had sagged at the front). It sounded very good but there ws too much gain. I sent it back to NVA for the top spec upgrade to the very best passive attenuators designed to cure the gain issue. Cost was £300. It was back with me in days, I don't know if the case was repaired or if it was a whole new case (I suspect the latter), anyway it looked absolutely mint with not a mark or scratch. The gain problem was completely solved, the knobs are obviously high quality expensive items, it feels like laboratory equipment in use. Sound quality was good from the off but seemed to improve over a week or two of use. I later found out this was entirely to be expected as each resistor on each step has to burn in.
I could not be happier with the product or the service. I will happily take the Pepsi challenge with this pre amp against *any* passive or active pre amp in existence (providing the power amp is not incompatible. I don't use an NVA power amp and I imagine it would work well with most power amps. I can always try that out if anyone is interested since I have several power amps lying around).
If it is possible to get the same performance from a much cheaper passive that is all well and good; I have to say I would have money on it that you cannot. Certainly the Tisbury passive which I have tried in exactly the same system was not remotely in the same league, although it is of course much cheaper.
As to cosmetics I wouldn't let a bit of wood and chrome blind me to mediocre performance; it seems to me a lot of kit these days is desigend so that you listen with your eyes and is not something for the serious enthusiast.
As far as material value is concerened the NVA 'philosophy' is that the only thing better than the best component is no component at all. That makes perfect sense to me.
I will happily take the Pepsi challenge with this pre amp against *any* passive or active pre amp in existence (providing the power amp is not incompatible. I don't use an NVA power amp and I imagine it would work well with most power amps. I can always try that out if anyone is interested since I have several power amps lying around).
Nice one. If I can be arsed buying one now, we'll do the comparison, as the main reason why I was going to buy the Khosmo passive in the first place was because of the superb stepped attenuator therein (as effectively I was getting a passive preamp for £95, along with a top-notch stepped attenuator), which Anthony and Joe had recommended, but now that I'm going for the remote control version of that stepped attenuator, there's no real need for the preamp itself.
However, if I don't buy one, I'll certainly bring my Croft preamp down and use that instead with your power amp. Remind me again which one it is? :)
Incidentally, as far as the use of acrylic cases is concerned, and please correct me if I'm wrong in terms of NVA design, I believe the main point is that it is non-ferrous (non-magnetic) - something which I also firmly believe in.
Therefore, as long as the casing material fits that criterion, it shouldn't matter, unless someone can educate me as to the special properties of acrylic, which make it sonically superior for a preamp casing, to any other non-ferrous material?
Marco.
Marco
yes we will do it, the proof is always in the pudding:)
Power amp is an XTZ
H'okay dokes - look forward to it! I'm sure that Anthony would also like to bring his Soul Mate preamp along for comparison, or if he can't make the show, I could bring one with me.
Perhaps some of the NVA boys attending the show would also like to hear that one? :)
Marco.
http://i132.photobucket.com/albums/q8/DSJR_photos/croft_Series7.jpg (http://s132.photobucket.com/user/DSJR_photos/media/croft_Series7.jpg.html)
http://i132.photobucket.com/albums/q8/DSJR_photos/croft_25.jpg (http://s132.photobucket.com/user/DSJR_photos/media/croft_25.jpg.html)
These have been described as untidy despite the cable ties 'dressing' the cables, yet Naim removed the ties on some of the NAC82 wiring and dressed the individual wires 'freely' 'cos they thought it improved performance..
anthonyTD
15-04-2014, 09:43
Hi Marco,
I try my best to stay well away from discussions concerning NVA, and its owner these days, [for obvious reasons] so, i will not be getting involved with product comparisons etc, and besides, the Soul-mate preamp is in a different league as far as price point, so' not a fair comparison.
I would like to comment on the quality of the Khozmo though, when you think the guy designed each part of it, [including the Attenuator] and builds each one from scratch, it does make you wonder how the heck he can do it for the price he sells them for, i predict that as his products gain popularity, the prices will start to go up considerably.
A...
No worries, matey, regarding the preamp comparison. I just thought that some folk might be interested in also having your design in the equation. You're right though - it's an unfair comparison.
I guess that also applies to the Croft, although since Martin is up for the demo, it will act as an interesting example of A/B-ing a top-notch valve preamp against a (reputedly) top-notch passive preamp. I'll also have my Copper amp on hand for alternative power amp comparison duties.
If someone could bring an NVA power amp along, then that would help ensure that at some point we can hear the P90, optimally, in its intended configuration.
Incidentally, as I know you're a fan of using acrylic cases on your equipment, are you aware of any sonic advantages of using that material other than the fact that it's non-magnetic? :)
Marco.
P.S Yup, get a Khosmo at that price while you can! A future 'classic' in the making, me thinks...
http://i132.photobucket.com/albums/q8/DSJR_photos/croft_Series7.jpg (http://s132.photobucket.com/user/DSJR_photos/media/croft_Series7.jpg.html)
http://i132.photobucket.com/albums/q8/DSJR_photos/croft_25.jpg (http://s132.photobucket.com/user/DSJR_photos/media/croft_25.jpg.html)
These have been described as untidy despite the cable ties 'dressing' the cables, yet Naim removed the ties on some of the NAC82 wiring and dressed the individual wires 'freely' 'cos they thought it improved performance..
Hi Dave,
I'm sure it does improve performance (I've never questioned that), but the fact that the wires inside the NVA passive were splayed out wasn't the reason why I thought it looked rather 'home-made' and unprofessional, in comparison with the Khosmo :)
I'm sure you'll agree that, whilst being tuned for maximum sonic performance, Glenn's designs are also very neatly laid out and superbly constructed, something that, IMO, cannot be said of the P90SA, which is on a par price-wise with the Croft Basic range of preamps.
The NVA unit just doesn't seem to have been built with 'love', or any sense of pride - more like thrown together as quickly as possible and churned out to meet a deadline. Just because you've built a piece of equipment for an employee doesn't excuse haphazard and shoddy workmanship.
Anthony's built/modified many things for me, and the standard of his workmanship is exemplary, and also consistent, regardless if it's been carried out for me, a customer he's known for years, or Tom, Dick or Harry.
Marco.
john dolan
15-04-2014, 10:48
The wires aren't exactly neat in my DIY Glasshouse
http://i61.tinypic.com/28wmiig.jpg
That's the one with Seidon attenuator and Elma selector switch.Mundorf 99%silver/1%gold wire and Audio Note silver plated RCA.Also updated with 2 Zfoils.
This Pre runs my Passion mighty close.
Pic of my silver Glasshouse with DACT and neat wires lol.
http://i58.tinypic.com/bduxw0.png
anthonyTD
15-04-2014, 11:10
Acrylic as a material has good damping characteristics when used in particular applications,however, i think the main reason people use it in Audio is because it is an insulator, and its quite easy to work with, ie; machine etc, and when used right,its quite a nice material aesthetically.
No worries, matey, regarding the preamp comparison. I just thought that some folk might be interested in also having your design in the equation. You're right though - it's an unfair comparison.
I guess that also applies to the Croft, although since Martin is up for the demo, it will act as an interesting example of A/B-ing a top-notch valve preamp against a (reputedly) top-notch passive preamp. I'll also have my Copper amp on hand for alternative power amp comparison duties.
If someone could bring an NVA power amp along, then that would help ensure that at some point we can hear the P90, optimally, in its intended configuration.
Incidentally, as I know you're a fan of using acrylic cases on your equipment, are you aware of any sonic advantages of using that material other than the fact that it's non-magnetic? :)
Marco.
P.S Yup, get a Khosmo at that price while you can! A future 'classic' in the making, me thinks...
john dolan
15-04-2014, 11:24
Tom Evans always uses it and must say I like my Michell Iso phono and Argo HR preamp he designed which is what the Vibe is based on.
http://i61.tinypic.com/anf1ar.png
john dolan
15-04-2014, 11:37
Here is my Glasshouse with Noble pot
http://i61.tinypic.com/2iqmrzd.jpg
Hi Dave,
I'm sure it does improve performance (I've never questioned that), but the fact that the wires inside the NVA passive were splayed out wasn't the reason why I thought it looked rather 'home-made' and unprofessional, in comparison with the Khosmo :)
Personally I've never taken the lid off any component, mainly because I'm not competent to fix anything electrical without a) breaking a wire or b) electrocuting myself or c) burning myself with a soldering iron, so as far as I'm concerned they can look as tidy or untidy as they like; the sound coming out is what matters.
anthonyTD
15-04-2014, 12:23
http://imagizer.imageshack.us/v2/xq90/838/sbw9.jpg
Sure, Joe - and the same used to apply to me, before I discovered the joys of having my kit modified to the kind of sonic standard for a fraction of the price that a high-end commercial manufacturer would charge! :)
Marco.
john dolan
15-04-2014, 12:27
Learn to DIY its good fun and you save yourself a fortune.
Start with cables they are they biggest price con in hifi.
http://imagizer.imageshack.us/v2/xq90/838/sbw9.jpg
Ah, another novel use of acrylic! Btw, good point about it being an insulator - I hadn't thought of that :)
Marco.
Learn to DIY its good fun and you save yourself a fortune.
I can imagine that it would be good fun, but I'm a listener not a builder. I'd rather suggest some mods that I think might improve my kit, and if my EE or DIY-orientated mates agree, ask them to expertly carry out the work on my behalf.
At the end of the day, it's the end result that interests to me the most, not the process leading up to it :)
Marco.
I can imagine that it would be good fun, but I'm a listener not a builder. I'd rather suggest some mods that I think might improve my kit, and if my EE or DIY-orientated mates agree, get them to expertly carry out the work on my behalf.
I wouldn't even know where to start on 'suggesting mods'. If I have something that can be upgraded, I send the thing off to the bloke who designed it, or to someone the designer approves to do mods, and let them weave their magic. That's what I did with my Tom Evans preamp and Border Patrol power amps.
That's fair enough. However, I've built up enough experience now to be able to understand why something might work, and also know intrinsically how my kit sounds, in order to ascertain whether when the mods have been carried out, if they have been a success or not.
I've successfully carried out that process umpteen times now with various parts of my system, from sources to speakers. I just leave the actual electronic work to an expert, a) to ensure than I don't end up killing myself or blowing up my equipment, and b) to ensure that the job is done to the required professional standard.
For me, it's a win-win! :)
Marco.
Can anyone comment on the sonic difference between an "attenuator" based passive (Kozmo, etc.) and a "LDR" based one (Tortuga Audio LDRx) for example ? Isn't a LDR based pre closer to not having anything in the signal path at all ?? It is much more expensive though around the same level the high-end VDM kit would be.
Thank's
I've always wondered about LDR attenuators too.. matching the components is the cost.
Then there are the other remote controlled, relay attentuators like what Lukasz Fikus uses in his Lampizator pre-amps - supposed to sound good too, although I think they are ladder attenuators adding further resistors into the path, additive attenuation?
I found this on their site which seems to indicate that the potentiometer is not in the signal path
Optically Isolated Signal Path - The audio signal is optically isolated from the power supply and the control circuitry. The audio signal only “sees” purely resistive LDRs. Electrical isolation between multiple incoming audio signals is well in excess of 5 mega-ohms.
More here http://www.tortugaaudio.com/what-is-a-passive-preamplifier/
Greets
Audio forums make me chuckle.
Only here can we see people buying mains cables for £700 interconnects at around £500 (or more) cartridges in the region of £2k (and up) and complain a pre-amp is not good value for money, as there is not much in there?
Who cares.
As long as it sounds good, and you are happy with your purchase, crack on if it makes you happy.
As for price, surely you pay for the time to design, build and test the equipment (development phase) as well as just the individual component cost and overheads.
Value for money is in the ear of the beholder.
anthonyTD
15-04-2014, 17:23
I have also heard the relay based attenuators, they are very good, they use either an encoder to switch the relays, or remote, the control circuits use a programed pic chip.
I've always wondered about LDR attenuators too.. matching the components is the cost.
Then there are the other remote controlled, relay attentuators like what Lukasz Fikus uses in his Lampizator pre-amps - supposed to sound good too, although I think they are ladder attenuators adding further resistors into the path, additive attenuation?
I've always wondered about LDR attenuators too.. matching the components is the cost.
Then there are the other remote controlled, relay attentuators like what Lukasz Fikus uses in his Lampizator pre-amps - supposed to sound good too,
although I think they are ladder attenuators adding further resistors into the path, additive attenuation?u
I bought an LDR pre amp kit last year prior to getting the NVA but it is stiil awiting building. Hopefully I will have it ready soon.
u
I bought an LDR pre amp kit last year prior to getting the NVA but it is stiil awiting building. Hopefully I will have it ready soon.
...and that is the other side of DIY ! Projects of the mind.. never getting made. My imaginary DIY hifi is AMAZING !!!!
I'm not making it myself, the double E who is reckons it is a simple job. That was six months ago although last time I checked I was 'in the diary' so some progress at least ;)
Audio forums make me chuckle.
Only here can we see people buying mains cables for £700 interconnects at around £500 (or more) cartridges in the region of £2k (and up) and complain a pre-amp is not good value for money, as there is not much in there?
It's not so much that there's not much in there, Kevin, but rather that what's in there looks somewhat 'unloved'. It wouldn't matter if I was spending £500 or £5000 on a preamp (or any other equipment): I want it to look like the designer cares about what he's doing and has pride in his workmanship.
If Glenn Croft can do that (as already shown), so can anyone else.
Marco.
Figlet108
15-04-2014, 21:37
All very interesting...
I bought my P90 of a member here for £90 delivered. It had a damaged case (top plate had sagged at the front). It sounded very good but there ws too much gain. I sent it back to NVA for the top spec upgrade to the very best passive attenuators designed to cure the gain issue. Cost was £300. It was back with me in days, I don't know if the case was repaired or if it was a whole new case (I suspect the latter), anyway it looked absolutely mint with not a mark or scratch. The gain problem was completely solved, the knobs are obviously high quality expensive items, it feels like laboratory equipment in use. Sound quality was good from the off but seemed to improve over a week or two of use. I later found out this was entirely to be expected as each resistor on each step has to burn in.
I could not be happier with the product or the service. I will happily take the Pepsi challenge with this pre amp against *any* passive or active pre amp in existence (providing the power amp is not incompatible. I don't use an NVA power amp and I imagine it would work well with most power amps. I can always try that out if anyone is interested since I have several power amps lying around).
If it is possible to get the same performance from a much cheaper passive that is all well and good; I have to say I would have money on it that you cannot. Certainly the Tisbury passive which I have tried in exactly the same system was not remotely in the same league, although it is of course much cheaper.
As to cosmetics I wouldn't let a bit of wood and chrome blind me to mediocre performance; it seems to me a lot of kit these days is desigend so that you listen with your eyes and is not something for the serious enthusiast.
As far as material value is concerened the NVA 'philosophy' is that the only thing better than the best component is no component at all. That makes perfect sense to me.
Martin, getting the P90SA for £390 is good value especially when you consider that the stepped attenuators are bought in at around £264 per pair. I was always happy with the sound of the P90SA. Good clean transparent sound and plenty of drive as you say. But then why wouldn't it sound good? It uses well deigned stepped attenuators by Neville Roberts (http://www.hificollective.co.uk/components/shinkoh_stepped_attenuator.html) with an Elma switch and Shinkoh resistors. While the fit and finish is not very professional with the top sagging (as there are no braces on the front and back panel to support it) and the knobs stick out and look a bit of a mess, none of that really bothered me. Oh, and incidentally I paid full price of £640 on Jan 6 2011 for my P90SA just like any ordinary customer, so I assume it was typical of the units going out at the time. Not sure if production has improved by now...
The problem I did have with mine was that the left channel was always just a bit louder than the right and I could never get them matched up properly. There are not enough steps (only 24) and the resolution of each step was too big to get the balance exactly right. If I got another SA I would want more steps for sure.
Ultimately I got rid of it not for any of those reasons, just that I didn't need it anymore when I replaced my NVA amps with the EAR 509s I bought on here. Those have a built in level control and allow me to plug my DAC directly into them without compromising digital attenuation.
However what I did find interesting before I got rid of the P90SA was buying that cheap stepped attenuator from ericyam on ebay and comparing them. On paper they are very similar in that they use a very similarly designed attenuator with 24 steps, silver wiring etc. The main difference as far as I could see were the Dale resistors instead of the Shinkohs. I personally couldn't hear that much difference. For me that's not so much a comparison of brands and products, but more a comparison of the resistors.
I've heard that resistors can make a big difference for some folks, but in this case I didn't experience it.
Anyway moving on, I too have always wondered about LDR pre amps and I too bought the Stereo Coffee LDR kit (http://www.ebay.co.uk/itm/Light-Dependant-Resistor-Single-input-Preamp-Kit-/291041024249?pt=AU_Electronics_Audio_Amplifiers&hash=item43c36598f9) which I think is the one you got? And I too have yet to build it despite having it for a good number of months now... :)
It would actually be really interesting to bake off the best of the stepped attenuators with an LDR such as this one.
i find Plexiglas cases make equipment look cheap... especially when inprecisely glued together... but then if it is good for the sound i suppose its ok.
Stratmangler
15-04-2014, 21:57
i find Plexiglas cases make equipment look cheap... especially when inprecisely glued together... but then if it is good for the sound i suppose its ok.
Them old plexi Marshalls are always in demand ....
http://en.wikipedia.org/wiki/Marshall_1959
the concept of the stereo coffee ldr got some challenging over at diyaudio,com... http://www.diyaudio.com/forums/vendors-bazaar/242373-light-dependant-resistor-3-input-preamp-kit-8.html
probably not because of the looks :-)
Figlet108
15-04-2014, 22:17
the concept of the stereo coffee ldr got some challenging over at diyaudio,com... http://www.diyaudio.com/forums/vendors-bazaar/242373-light-dependant-resistor-3-input-preamp-kit-8.html
Hi Rupert, yes I can see poor Chris isn't very popular on diyaudio and frankly without a PhD in electronics I think I'd be too afeared to show my face on there... :)
However the proof is in the eating and the meal hasn't been prepared yet, so we'll see. And for the £38 that it cost me I don't really care that much if it's a dud...
Anyway moving on, I too have always wondered about LDR pre amps and I too bought the Stereo Coffee LDR kit (http://www.ebay.co.uk/itm/Light-Dependant-Resistor-Single-input-Preamp-Kit-/291041024249?pt=AU_Electronics_Audio_Amplifiers&hash=item43c36598f9) which I think is the one you got? And I too have yet to build it despite having it for a good number of months now... :)
It would actually be really interesting to bake off the best of the stepped attenuators with an LDR such as this one.
hi Jason !
why dont you ask the guy at tortuga to send you one for the bakeoff i would be very interested in a comparison
However the proof is in the eating and the meal hasn't been prepared yet, so we'll see. And for the £38 that it cost me I don't really care that much if it's a dud...
is true !
Martin, getting the P90SA for £390 is good value especially when you consider that the stepped attenuators are bought in at around £264 per pair. I was always happy with the sound of the P90SA. Good clean transparent sound and plenty of drive as you say. But then why wouldn't it sound good? It uses well deigned stepped attenuators by Neville Roberts (http://www.hificollective.co.uk/components/shinkoh_stepped_attenuator.html) with an Elma switch and Shinkoh resistors. While the fit and finish is not very professional with the top sagging (as there are no braces on the front and back panel to support it) and the knobs stick out and look a bit of a mess, none of that really bothered me. Oh, and incidentally I paid full price of £640 on Jan 6 2011 for my P90SA just like any ordinary customer, so I assume it was typical of the units going out at the time. Not sure if production has improved by now...
The problem I did have with mine was that the left channel was always just a bit louder than the right and I could never get them matched up properly. There are not enough steps (only 24) and the resolution of each step was too big to get the balance exactly right. If I got another SA I would want more steps for sure.
Ultimately I got rid of it not for any of those reasons, just that I didn't need it anymore when I replaced my NVA amps with the EAR 509s I bought on here. Those have a built in level control and allow me to plug my DAC directly into them without compromising digital attenuation.
However what I did find interesting before I got rid of the P90SA was buying that cheap stepped attenuator from ericyam on ebay and comparing them. On paper they are very similar in that they use a very similarly designed attenuator with 24 steps, silver wiring etc. The main difference as far as I could see were the Dale resistors instead of the Shinkohs. I personally couldn't hear that much difference. For me that's not so much a comparison of brands and products, but more a comparison of the resistors.
I've heard that resistors can make a big difference for some folks, but in this case I didn't experience it.
Anyway moving on, I too have always wondered about LDR pre amps and I too bought the Stereo Coffee LDR kit (http://www.ebay.co.uk/itm/Light-Dependant-Resistor-Single-input-Preamp-Kit-/291041024249?pt=AU_Electronics_Audio_Amplifiers&hash=item43c36598f9) which I think is the one you got? And I too have yet to build it despite having it for a good number of months now... :)
It would actually be really interesting to bake off the best of the stepped attenuators with an LDR such as this one.
Hi Jason
That's all fair comment, I am not suggesting that it is impossible to get comparable quality for less, I have not tried everything on the market by a long way. it is just that your precious post read like an unwarrented slagging of a bit of kit that I really rate. I've not had an issue with getting correct volume in fact that is one of the thngs I really like about the P90SA
Re the LDR pre-amp I cannot recall what the make is of the kit I have bought but it is not the one you are referring too. It is from Australia and cost me about £160. On paper it should be the most transparent pre possible but that doesn't necessarily translate into good performance in the real world. Got a few days off from tomorrow so I might drop in to the pro shop and see how far up the queue I have moved.
Figlet108
16-04-2014, 14:31
...it is just that your precious post read like an unwarrented slagging of a bit of kit that I really rate...
Well I do my best Martin, but I don't think it was the best post I've ever made :)
Seriously though, I feel that's a rather unfair comment. If you re-read my original post you'll see that first I posted some photos without any comment or criticism. This was in the spirit of John Dolan's photos of pre innards. I personally really like it when folks post the insides of stuff.
And then the only comment I made was that it was no better than a cheaper pre off ebay. I never said that both these pre's weren't good, they are both good and I've said so.
On the other hand you stated "Certainly the Tisbury passive which I have tried in exactly the same system was not remotely in the same league, although it is of course much cheaper."
I would say that's a greater condemnation for Tisbury than anything I said in my original post. I'm sure lots of Tisbury fans were unhappy that there favourite pre was put down.
What do you think?
Re the LDR pre-amp I cannot recall what the make is of the kit I have bought but it is not the one you are referring too. It is from Australia and cost me about £160. On paper it should be the most transparent pre possible but that doesn't necessarily translate into good performance in the real world. Got a few days off from tomorrow so I might drop in to the pro shop and see how far up the queue I have moved.
Ok, I think I know which one it is. Well let's see which one of us get their LDR built first :)
I still think on paper LDRs should give the best of the pres a run for their money...
great ! maybe some competition will get these LDR attenuators finally built :cool:
Hi Rupert, yes I can see poor Chris isn't very popular on diyaudio and frankly without a PhD in electronics I think I'd be too afeared to show my face on there... :)
It's ok, just go on there and get ignored like I do..
i find Plexiglas cases make equipment look cheap... especially when inprecisely glued together... but then if it is good for the sound i suppose its ok.
Not if you can see the expensive looking insides:
http://www.positive-feedback.com/Issue39/images/P1013119.jpg
DNM. Every other month used to see revised boards at one time and there's little to no hard wiring inside. ;)
Yep, I thought I read "DNM"... do they sound any good ? kinda reminds me of the old Quad 33 which also has little boards inside.
I see they even have pre amps "the most transparent pre amp..." .. look's interesting
12082
I've had some DNM and still have an older DNM pre around.
Very nice they are - detailed and full of energy. The amps are really good too - they are low powered but sound so much more powerful than some amps more than twice the rated power.
Problem with some older ones is they're not good with today's line levels, newer versions are different designs. Those photos are the new 3D versions and are about £5k upwards, depending on power supply level. 3D in that the older models were 3, 3A, 3B, 3C..
Still surprised though that after all these years, they still used the same Colvern pots.. are they that good? I had to change some on one I had and they weren't audiophile expensive, about £20 each maybe..
Yep, I thought I read "DNM"... do they sound any good ? kinda reminds me of the old Quad 33 which also has little boards inside.
I see they even have pre amps "the most transparent pre amp..." .. look's interesting
12082
P.s. they used to be made in Switzerland too I think.. by Reson. The clear cased ones are special models, normally they are a dark, smoked acrylic.
Think they're made in the UK now.
Well I do my best Martin, but I don't think it was the best post I've ever made :)
Seriously though, I feel that's a rather unfair comment. If you re-read my original post you'll see that first I posted some photos without any comment or criticism. This was in the spirit of John Dolan's photos of pre innards. I personally really like it when folks post the insides of stuff.
And then the only comment I made was that it was no better than a cheaper pre off ebay. I never said that both these pre's weren't good, they are both good and I've said so.
On the other hand you stated "Certainly the Tisbury passive which I have tried in exactly the same system was not remotely in the same league, although it is of course much cheaper."
I would say that's a greater condemnation for Tisbury than anything I said in my original post. I'm sure lots of Tisbury fans were unhappy that there favourite pre was put down.
What do you think?
Ok, I think I know which one it is. Well let's see which one of us get their LDR built first :)
I still think on paper LDRs should give the best of the pres a run for their money...
Okay - 'precious' should have been 'previous', that was an unfortunate typo. And you are correct you did just post a picture it was Marco who commented on there 'not being much inside'. So please accept my apologies.
As far as the Tisbury is concerned I reserve my right to comment favourably or unfavourably on anything I have heard especially if it is in my own system. That is one of the mainstays of a hi fi forum and one reason why they are so much better than mag reviews if you want to get a good idea of whether something is worth trying or not. As I recall only one other member here who has tried the Tisbury has commented on its lack of slam and attack. This I put down to partnering equipment, the sort of music pkayed, the volume used and expectation level. Its strengths were such that I decided passive was worth pursuing and purely by chance the NVA came up for sale not long after at an acceptable price for taking a punt. It is superior to the Tisbury in every respect and I am pretty confident that would be the case in any system, within reason. I have a lot of kit to hand including different speakers so can put together a fair gew digferent combos myself quite easily to test that, something magazine reviewers rarely do. It is of course much more expensive but I did also point that out. My only commeny to hppy Tisbury owners who are disgruntled by what I wrote would be to say that you can do better if you are prepared to spend a bit more. Not always true in the hi fi world but it is the case in this situation. Hope that clarifies things a bit more. I dont have any loyalty to a brand or manufacturer, if I like it then it stays until it dies or I find something better.
Figlet108
16-04-2014, 19:50
And you are correct you did just post a picture it was Marco who commented on there 'not being much inside'. So please accept my apologies.
Thank you Martin, I appreciate the courtesy.
As far as the Tisbury is concerned I reserve my right to comment favourably or unfavourably on anything I have heard especially if it is in my own system. That is one of the mainstays of a hi fi forum and one reason why they are so much better than mag reviews if you want to get a good idea of whether something is worth trying or not.
Well said sir! I believe this is *exactly* my point, and still applies even if it refers to the NVA brand ;)
For the record I have never said that NVA sounded bad. My criticisms of the products in general is that, for me, there is a lack of production quality and they look and feel like what they are: home made. In the specific case of the P90SA I also think there is better value for money out there.
I believe that having spent as much money as I have with NVA and as much time as I have living with NVA products I too reserve my right to comment favourably or unfavourably.
Now, this thread has inspired me to build my LDR, so you won't hear from me again until I do :)
With the stereo coffee ldr kit was else do you need to buy? Anyone made one yet?
Sovereign
16-04-2014, 22:54
Thank you Martin, I appreciate the courtesy.
Well said sir! I believe this is *exactly* my point, and still applies even if it refers to the NVA brand ;)
For the record I have never said that NVA sounded bad. My criticisms of the products in general is that, for me, there is a lack of production quality and they look and feel like what they are: home made. In the specific case of the P90SA I also think there is better value for money out there.
I believe that having spent as much money as I have with NVA and as much time as I have living with NVA products I too reserve my right to comment favourably or unfavourably.
Now, this thread has inspired me to build my LDR, so you won't hear from me again until I do :)
Bloody hell its Figlet! Welcome mate ;-)
For the record I have never said that NVA sounded bad. My criticisms of the products in general is that, for me, there is a lack of production quality and they look and feel like what they are: home made.
That's precisely my stance with the NVA preamp in question (and a lot of their other stuff I've seen): 'the home-made look' factor. That sort of thing doesn't bother me when dealing with DIY kit, but I expect commercially produced items, especially ones that have been on the market now for many years, to be more professionally finished.
The fact is, you can achieve superb sound without sacrificing the build quality of equipment, and also without it costing the earth. You just have to sufficiently care! ;)
Marco.
and maybe a little love too ?
That's precisely my stance with the NVA preamp in question (and a lot of their other stuff I've seen): 'the home-made look' factor. That sort of thing doesn't bother me when dealing with DIY kit, but I expect commercially produced items, especially ones that have been on the market now for many years, to be more professionally finished.
The fact is, you can achieve superb sound without sacrificing the build quality of equipment, and also without it costing the earth. You just have to sufficiently care! ;)
Marco.
I am not the world's greatest photographer and my camera is a bit basic but I don't personally think this looks shabbily built or 'homemade' (in a derogatory sense):
http://i903.photobucket.com/albums/ac233/Macca_photos_2009/p90001.jpg (http://s903.photobucket.com/user/Macca_photos_2009/media/p90001.jpg.html)
They are hand built to order by one person so comparisons with something from a multi-million pound production line operation are not going to be relevant.
I will find out the exact breakdown of parts, labour and profit in this product and report back...
Okay cost of P90SA pre-amp. 50% of the selling price is the parts and labour The other 50% is the profit.
So if sold by a typical hi-fi manufacturer - distributer - dealer set up we can estimate it would cost at a minimum £1K up to say £1.5K. Stick a High End badge on it and bling up the case you could perhaps add a zero to those prices.
Edit - got this slightly wrong, now amended.
The Black Adder
17-04-2014, 10:33
The TVC passives that use the S&B transformers are excellent... Had one in my system, I would be quite happy with that but whilst the Croft has a little more drive the TVC had more air to it... So it's about choosing your poison really.
I believe that I've now got a very good balance with using the Khozomo in the Croft.
I am not the world's greatest photographer and my camera is a bit basic but I don't personally think this looks shabbily built or 'homemade' (in a derogatory sense):
Nope - not until the lid is taken off and a 'multitude of sins' hidden underneath is revealed, including a 'lack of love' from the maker, as discussed. Ultimately, that will bother some folk more than others. For me, it boils down to pride of workmanship, or lack thereof.
That 'out of sight, out of mind' mentality is akin to tidying your house in preparation for some visitors arriving: do you spend time hovering or just brush all the dirt and dust under the rug? The superficial effect is the same, as on the surface, the room appears to be clean - and no-one will know any differently unless they look under the rug, but of course the room isn't clean.
Anyway, I've said enough on the matter. NVA kit is hardly alone in the respect of looking somewhat home-made (and aesthetics/build quality is a personal thing), so it would be unfair of me to single it out. The most important thing is sound quality, and we'll discover what happens there at your bake-off :)
Marco.
Well what I know about building audio equipment (with the possible exception of speakers since I have designed/built/modified some) could be written on a postage stamp. So here again is the picture that Jason posted of the internals of his P90. Specifically what is wrong here? I've no agenda here just would like to hear opinions from anyone who does build kit:
http://i903.photobucket.com/albums/ac233/Macca_photos_2009/2014-04-1312_37_29_resize.jpg (http://s903.photobucket.com/user/Macca_photos_2009/media/2014-04-1312_37_29_resize.jpg.html)
My opinion is probably moot as I don't build my own kit but two things stand out for me, one of which is probably me being pernickety therefore we will address this one first: I note that the input selector knob sits closer to the facia than its counterparts which triggers my OCD tendencies. I realise this is down to me and that it won't bother most people. The second slight issue for me is the wire routing. There may be a very good reason why they are laid out in the manner they are but would it not be better for SQ if the red & blue wires from each pot were routed directly across the case to their relevant positions rather than diagonally, thus crossing under the two cream wires? To put it simply, is the shortest signal path not the better option?
Well what I know about building audio equipment (with the possible exception of speakers since I have designed/built/modified some) could be written on a postage stamp. So here again is the picture that Jason posted of the internals of his P90. Specifically what is wrong here? I've no agenda here just would like to hear opinions from anyone who does build kit:
http://i903.photobucket.com/albums/ac233/Macca_photos_2009/2014-04-1312_37_29_resize.jpg (http://s903.photobucket.com/user/Macca_photos_2009/media/2014-04-1312_37_29_resize.jpg.html)
It isn't the tidiest by any means, nor is it the untidiest, but being overly tidy can cause all sorts of other problems like crosstalk between unshielded wires, but this pre shouldn't suffer from that as only one cable pair route is active at any one time.
It would bother me not a great deal if it was giving me what I wanted from it ;) The glued on lid would also make me think twice about satisfying any curiosity I might have, but again, if it was doing it's job perfectly I would see no need at all to crack it open in the first instance.
Some who might have thought processes different to mine might liken it though to having the Mona Lisa painted onto the back of a cornflakes packet :eek:
Martin,
I think I've said enough about the build quality of the NVA preamp in question.
All I will mention is that if you look at how the Khosmo preamp has been built (from the pics posted earlier) - and for a mere £195, including a stepped attenuator, which I believe is every bit as good, sonically, as that used in the P90SA, which costs £700 (although that theory has still to be tested), and compare it to the above, then you should understand where I'm coming from.
If not, there's really no point in continuing this part of the discussion, as we simply have a difference of opinion :)
Marco.
istari_knight
17-04-2014, 12:34
.
Gordon Steadman
17-04-2014, 12:44
This is an old argument that the two sides will never agree on.
For me, its the same as the comments I get about pride of workmanship in woodwork. I spend a considerable amount of my time restoring antique furniture. Some of the most expensive, desirable and best looking bits of furniture have the crappiest, unfinished 'unseen' bits you can imagine. The maker concentrated on the 'important' bits. They are meant to be seen and used and thats where the money went.
My guitars are the same. If it didn't make a difference to the sound, I sure as hell wouldn't spend the hours it takes to smooth off the bits inside that no-one would ever see. I take plenty of pride in my work but I won't waste valuable time that has to be costed in.
If it looks good, works well and sounds good - end of the argument as far as I'm concerned. Only if the neatness of the wiring makes a sonic difference can it matter, surely?
Firebottle
17-04-2014, 12:45
I build kit, so here is my humble opinion:
I have to agree with Dave about the unequal distances the control knobs are from the front panel. The attenuator shafts should be cut shorter so all knobs are close to the panel.
The wire routing is no problem but I would have made the red and blue wires a little shorter.
The glaring no-no is having unsupported unsleeved joints, the one red and one blue wire to the input resistors of the attenuators, plus the output wires to the screened cables.
:rolleyes: Alan
Martin,
If not, there's really no point in continuing this part of the discussion, as we simply have a difference of opinion :)
Marco.
We don't have a difference of opinion since I have *no* opinion either way, I have no idea if it is good or bad construction/layout since I know nothing about building amplifiers, passive or otherwise. You raised the issue of build quality of the P90 so now we are discussing it. Sorry if that appears fractious, it is not meant to be but if someone posted the internals of your Croft pre-amp and suggested it was built without care would you not want to find out if that was true or not? I think where we both agree is that it probably does not have any impact on the sound either way.
So oaky in the interests of peace and harmony let us leave it there, thanks to those EEs who have commented already.
£700 is about the same price as the LDR from Tortuga. I would be extremely interested to get a direct comparison between the two. I know it is asking a lot but could someone taking part at the bake-off ask Morten at Tortuga for a test unit ? He is a really nice person and probably could send one for the event.
edit: some pics of the LDR here (http://www.diyaudio.com/forums/vendors-bazaar/230114-tortuga-audio-ldr3x-diy-preamp-controller-w-remote-12.html#post3861204)
not much in it to look at but a lot of R&D and software in it.
12089
Gordon Steadman
17-04-2014, 13:17
By the way, are we to assume that this is a bog standard bit of NVA kit rather than one that has been modified in any way? I can't really imagine any manufacturer leaving shafts a different length as it shows so obviously.
We don't have a difference of opinion since I have *no* opinion either way, I have no idea if it is good or bad construction/layout since I know nothing about building amplifiers, passive or otherwise.
Sorry, my impression was that you thought it looked ok, which of course I don't, hence the difference of opinion.
You raised the issue of build quality of the P90 so now we are discussing it.
I simply said that for £195 (with a high-quality stepped attenuator fitted as standard), the Khosmo, IMO, offered better fit and finish, internally and externally than the NVA, and likely sounded just as good. The latter, of course, has still to be proven.
Sorry if that appears fractious, it is not meant to be but if someone posted the internals of your Croft pre-amp and suggested it was built without care would you not want to find out if that was true or not? I think where we both agree is that it probably does not have any impact on the sound either way.
I think it's already been proven (from previous pictures supplied) that Croft preamps are superbly constructed, even the entry-level models on a par, price-wise, with the NVA, whilst ensuring that they are tuned for maximum performance. If you can't tell the difference between them, Martin, in that respect, then there's not much more I can say.
When I bought my Croft preamp, it looked much better than it does now, simply because I've modified it for ultimate sonic performance, and so have had to make some aesthetic compromises, internally and externally, in order to achieve that. That doesn't bother me one iota, nor what anyone thinks of how it looks.
The point is, when the amp left Glenn originally, it was a professionally finished product, built inside and out by someone who has a pride in his workmanship, which is not something I can say for the P90SA in question. I'm sorry, but that's really all I have to say on the matter.
Marco.
By the way, are we to assume that this is a bog standard bit of NVA kit rather than one that has been modified in any way? I can't really imagine any manufacturer leaving shafts a different length as it shows so obviously.
Apparently the manufacturer concerned couldn't be arsed fixing it, as the job was a "pain in the arse" to do, which for me says it all. It's precisely that sort of lackadasicial attitude I'm referring to.
An amplifier designer of any merit should always strive to achieve the highest possible standards of construction within the available budget, inside and out of their equipment, whether something impacts directly on sound quality or not.
Marco.
john dolan
17-04-2014, 14:30
Would take but 30 seconds to saw the attenuator shafts so all the knobs lined up level.
Gordon Steadman
17-04-2014, 14:33
Would take but 30 seconds to saw the attenuator shafts so all the knobs lined up level.
I would have thought it rather easy to establish that this is a standard issue problem or not:scratch:
Figlet108
17-04-2014, 14:53
By the way, are we to assume that this is a bog standard bit of NVA kit rather than one that has been modified in any way? I can't really imagine any manufacturer leaving shafts a different length as it shows so obviously.
Yes Gordon, standard issue. Paid full price off ebay just like everyone else. No modifications.
The other unnecessary sloppiness is the lack of support at the front and back panels for the top panel to rest on.
Any pressure on the top panel will bend it and push it down, and very quickly you have a warped panel that is permanently sunk below.
Martin, I'm curious since you have a recent incarnation: have any of these issues (uncut shafts and unsupported top panel) been addressed in the current production models?
I build kit, so here is my humble opinion:
I have to agree with Dave about the unequal distances the control knobs are from the front panel. The attenuator shafts should be cut shorter so all knobs are close to the panel.
The wire routing is no problem but I would have made the red and blue wires a little shorter.
The glaring no-no is having unsupported unsleeved joints, the one red and one blue wire to the input resistors of the attenuators, plus the output wires to the screened cables.
:rolleyes: Alan
I don't know what's gone on with the control knobs as every NVA piece of gear I've used hasn't had this problem. In fact I was using a P90sa just a couple of weeks ago and the knobs were perfectly aligned...
istari_knight
17-04-2014, 15:25
Word on the street is Figlet and NVA have a "history" which I didn't know. With that now in mind I'm unwilling to critique based on that picture provided as its likely not representative of the real mccoy. Its obviously been posted by someone with an axe to grind.
Yes Gordon, standard issue. Paid full price off ebay just like everyone else. No modifications.
The other unnecessary sloppiness is the lack of support at the front and back panels for the top panel to rest on.
Any pressure on the top panel will bend it and push it down, and very quickly you have a warped panel that is permanently sunk below.
Martin, I'm curious since you have a recent incarnation: have any of these issues (uncut shafts and unsupported top panel) been addressed in the current production models?
Again, I don't get this, the case aside from the top panel isn't going anywhere, it's permanently bonded. The top is glued to help with servicing. And it's a dinky unit, people shouldn't be putting any pressure on the top panel anyway!
NVA is idiosyncratic gear, but as a friend said "the man does make some damn fine amps."
As for unsleeved joints, again, so what? There's no way they're going to be shorting out on anything... My units have always looked great, sounded great and as I "read the fucking manual" have never had problems with them.
Don't like the tone of this thread...
Haselsh1
17-04-2014, 15:31
I simply cannot agree that Croft amplifiers are "superbly constructed" from my own personal experience. The ones I had certainly were not.
I'am sure NVA would be happy to put there amps in better cases for another £500.
Of the units i've seen all are fit for purpose and sound very good.
Have to say i'am not sure why people would want to take the lids off there stuff unless they are going to diy it.
My amp may be filled with sand but it makes no odds as long as it sounds good.
From sitting on the sideline for the majority of this thread, there has to be some kind of story deeper than what is being told. If I bought that off ebay, and paid full price, I would have raised a case against the vendor, and either demanded a full refund or a replacement product. Obviously you didn't and are no longer happy with the product. This kind of action baffles me.
When you bought it, were you happy?
To me it looks like a Prototype built to prove the product and test.
It also seems a bit of bad form slagging off a manufacturer who can't reply on an open forum.
I'm not interested in the history one bit, and I don't really want to know the reasons why the ban was put in place, as I assume people had their reasons, but constructive criticism is all well and good.
Does it sound good? Is the sound that it produces good value for money? That is all I care about.
If it looks good externally, it helps get the mod of approval from Mrs. H
...Specifically what is wrong here? ...
http://i903.photobucket.com/albums/ac233/Macca_photos_2009/2014-04-1312_37_29_resize.jpg (http://s903.photobucket.com/user/Macca_photos_2009/media/2014-04-1312_37_29_resize.jpg.html)
it's glued together. why would anyone want to glue all the panels together ?
Using glue only makes production take longer (curing time), less precise (man look at those glue marks!), less strong, etc. and renders the finished product less professional looking...
To avoid metallic parts (screws) Nylon screws could be used.. if that is the (official) reason for doing so..
Please note that i am only commenting on the build quality. I think we all agree NVA gear is renowned for upper end sound quality...
Maybe it is the glue that makes them sound so good ? if so i take above comments back.
oh jeez here we go .. the censors are out again .. don't read it if you don't like the tone .. there is no hidden agenda ffs .. the build quality is being discussed
why not stick the electronics in a cardboard and save 150 quid ??
What's the issue with gluing things together?
Why take the lid off in the first place?
What's the issue with gluing things together?
It's a right PITA if you want to post pictures of the innards of your amp on an internet forum so that people can guess what the designer's intentions were.
A really valid reason then. :doh:
oh jeez here we go .. the censors are out again .. don't read it if you don't like the tone .. there is no hidden agenda ffs .. the build quality is being discussed
why not stick the electronics in a cardboard and save 150 quid ??
Well I already read it, how am I supposed to pre-read forum posts? I read it, I responded. Yes, a thread has turned from "have you tried a Khozmo passive" to "ohhh look at that shoddy NVA construction". Well that picture certainly looks NOTHING like the P90sa I used, so something's up with it...
the let it die its natural death
Why take the lid off in the first place?
:exactly:
istari_knight
17-04-2014, 16:07
I didn't even see any constructive criticism, just plain old slagging off... People http://i26.photobucket.com/albums/c129/istari_knight9/Other/shitstir_zpsa001697a.gif should be at least be warned if not sin binned IMO.
I neither have nor want any but he must be doing something right as he's still in business, still manufacturing in the UK, still has a loyal user base, still prices very competitively, I've never seen a faulty one & s/h examples rarely come up for sale.
am i entitled to express my opinion on the build quality of these amps ? or is that now considered slagging some one ??
Gordon Steadman
17-04-2014, 16:35
Regarding Figlet's comments about NVA stuff, it is impossible to ignore that fact that there has been personal animosity between him and the manufacturer of NVA equipment because of a failed commercial relationship (I don't speak from personal knowledge here but the fact has been acknowledged elsewhere).
With this knowledge it is impossible to accept that any criticism does not have an ulterior motive. His earlier comment about this pre being standard issue is denied elsewhere as it was converted from a pot based pre to stepped attenuator.
Figlet108
17-04-2014, 17:06
Let me just very quickly address this point first:
https://lh5.googleusercontent.com/-MnqRP7LvjJg/U1AJNYMNG-I/AAAAAAAACS8/CZN4lZ6HCas/w470-h565-no/Screen+Shot+2014-04-17+at+17.52.36.png
I'm up for a robust debate but let's not stoop to outright lies...
This was a standard P90SA purchase bought along with a TSS amp and cable totalling £1800 (I have all the invoices)
No modifications were made.
Figlet108
17-04-2014, 17:24
Word on the street is Figlet and NVA have a "history" which I didn't know. With that now in mind I'm unwilling to critique based on that picture provided as its likely not representative of the real mccoy. Its obviously been posted by someone with an axe to grind.
Hi James, I appreciate your comments and yes things did end badly with me and NVA. However, everything was resolved to my satisfaction in the end without any remaining chips on my shoulder and I only wish NVA all the best and I'm sure they will continue to be successful. The products sound good as I have always said and continue to say.
However as I think we already established with Martin, I have the right to comment positively or negatively on products I have owned and have experience of. If you look at the sum total of my 5 or so posts I have simply said that while the pre sounds good, I believe you can get the same or better for less. And I mentioned a couple of things I didn't like about the case and the channel balance.
That's it. I never made any comments about the insides or any other negative comments, some of which I personally think were a bit OTT and unnecessary. Other people took my photos and made many comments that I did not contribute to or wish to be a part of.
Selby, the original poster started a thread about pres and I contributed following Martin's comments to provide a different point of view to the pre he mentioned.
If others want to turn this into something ugly and start accusing me of ulterior motives that's fine. But my comments are from personal experience and are as true and objective as I can make them. And I will reiterate that the pre shown is exactly what I was sent. I already said the case imperfections etc didn't bother me that much and were not the reason I moved it on.
Figlet108
17-04-2014, 17:33
Why take the lid off in the first place?
Because it takes all sorts of people to make a world. Some people like to take things apart and try and understand how they work or are put together. I've been taking things apart since I was 5 - it's just an affinity. The first thing I do with any new kit is open it up and have a look. It's part of the ritual of a new purchase and I enjoy that aspect of buying stuff as much as any other aspect.
And I'm not the only one. If you frequent the more DIY focussed forums like DIYaudio or AudioTalk it's fairly standard procedure to take stuff apart and see how it ticks.
Figlet108
17-04-2014, 17:40
...It also seems a bit of bad form slagging off a manufacturer who can't reply on an open forum...
Kevin, all good points which I think I've already addressed.
As to bad form, go and have a look at the other forum and then come back here and talk to us about bad form.
I've stated my opinions and experiences just like folks do all over forums for all sorts of kit. No untrue or unfair slagging off in any of my posts as far as I'm concerned.
Is there any reason why a competent equipment manufacturer wouldn't welcome pictures being taken of ANY part of their equipment, either of the inside or outside?
The fact is, if there was nothing arguably shoddy or sub-standard, under the hood or otherwise, to highlight in the first place, then there would be no ammunition for anyone with an ulterior motive to use against the manufacturer of that equipment.
Marco.
As to bad form, go and have a look at the other forum and then come back here and talk to us about bad form.
Indeed. Kevin, you should direct the very same remark at those in charge elsewhere, in reference to their comments about this forum and some of its members, where slagging things off is a way of life.
Marco.
Gordon Steadman
17-04-2014, 17:57
Indeed. Kevin, you should direct the very same remark at those in charge elsewhere, in reference to their comments about this forum and some of its members, where slagging things off is a way of life.
Marco.
That is no reason to appear to use this opportunity to have a pop. Why lower yourself you a level you clearly despise.
Figlet108
17-04-2014, 18:03
Anyway, let's move on and get back to helping Selby with his search for Passive Pres.....
To that end, I have quickly thrown together the Stereo Coffee LDR (http://www.ebay.co.uk/itm/Light-Dependant-Resistor-Single-input-Preamp-Kit-/291041024249?pt=AU_Electronics_Audio_Amplifiers&hash=item43c36598f9) I mentioned before (I've only had it lying around for 6 months!):
https://lh3.googleusercontent.com/-g-2hcJPCU2c/U1AVMLqB-PI/AAAAAAAACTc/fiP86V9R_Xg/w849-h566-no/2014-04-17+18.23.27_resize.jpg
https://lh6.googleusercontent.com/-aEBfRxGkAaI/U1AVMHhYQzI/AAAAAAAACTg/e7DkKBJh1TU/w849-h566-no/2014-04-17+18.23.47_resize.jpg
It was really easy to put together and just needs a power supply building (or buying) and putting in a case.
I haven't actually put it in a system yet and heard it - just about to :guitar:
Certainly from a simplicity and low component count I like it already, but let's see what it sounds like...
Is there any reason why a competent equipment manufacturer wouldn't welcome pictures being taken of ANY part of their equipment, either of the inside or outside?
The fact is, if there was nothing arguably shoddy or sub-standard, under the hood or otherwise to highlight in the first place, then there would be no ammunition for anyone with an ulterior motive to use against the manufacturer of that equipment.
Marco.
There is nothing wrong with the internals though Marco, it is electrically safe and done for sonic reasons. However those wonky knobs look like a mistake, as I've mentioned, my unit looked immaculate from the outside.
That is no reason to appear to use this opportunity to have a pop. Why lower yourself you a level you clearly despise.
Yes, but I don't consider that's happening here. Also, that's very easy to say, Gordon, for someone not continually on the receiving end of any abuse.
Jason has, IMO, more than justified his contributions on this thread, and I've simply commented on what I've seen, based on the picture he posted of the NVA preamp in question. All I've done is compared it with a passive preamp from another manufacturer I think is far better built and probably sounds as good for considerably less money.
Should I just shut up and keep my opinions to myself, simply because it might upset the designer of said preamp and some of the users of his equipment?
Marco.
There is nothing wrong with the internals though Marco, it is electrically safe and done for sonic reasons.
I've never said otherwise, Neil; merely that, in my opinion, it doesn't appear to have been built with much love - and I stand by that view.
Marco.
Gordon Steadman
17-04-2014, 18:12
Yes, but I don't consider that's happening here. Also, that's very easy to say, Gordon, for someone not continually on the receiving end of any abuse.
Jason has, IMO, more than justified his contributions on this thread, and I've simply commented on what I've seen, based on the picture he posted of the NVA preamp in question, and compared it with passive preamp from another manufacturer I think is far better built and probably sounds as good for considerably less money.
Should I just shut up and keep my opinions to myself?
Marco.
Not at all but knowing that there is an accusation that this pre is not the work of the NVA manufacturer, any opinion on the standard of construction is invalid.
I have no personal interest in this, I stopped posting at HFS because I found the level of vitriol offputting. I find the attacks here equally offputting and it affects my enjoyment of the forum. It is impossible to rid myself of the feeling that there is an injection of personal animosity in all this from both of you. Sorry if its not true but I don't see how you could avoid it.
Figlet108
17-04-2014, 18:21
...However those wonky knobs look like a mistake, as I've mentioned, my unit looked immaculate from the outside.
Neil, I believe you. I have no problem in believing that all other P90SAs sold have non-wonky knobs. But mine was as shown.
Not at all but knowing that there is an accusation that this pre is not the work of the NVA manufacturer, any opinion on the standard of construction is invalid.
...an accusation that so far has not been proven; indeed, in my view Jason has provided more than enough evidence to the contrary.
I have no personal interest in this, I stopped posting at HFS because I found the level of vitriol offputting. I find the attacks here equally offputting and it affects my enjoyment of the forum. It is impossible to rid myself of the feeling that there is an injection of personal animosity in all this from both of you. Sorry if its not true but I don't see how you could avoid it.
I won't deny that, as like you say it's impossible to avoid it, so perhaps instead you could make allowances for that and appreciate things from my perspective? After all, we're all only human.
Anyway, I was simply being honest, regardless that the preamp in question was an item from NVA. I can assure you that my comments would've been identical had the preamp been made by anyone else.
Marco.
Indeed. Kevin, you should direct the very same remark at those in charge elsewhere, in reference to their comments about this forum and some of its members, where slagging things off is a way of life.
Marco.
My point is that the other forum, from what I have read talks about goings on here and elsewhere on similar forums. It can make interesting reading, but I tend not to get involved in that type of discussion. That's not my "thing".
Some of the comments posted on here could be damaging to the livelihood of certain manufacturers, and in extreme cases, you, as the owner (if I am correct) of the forum could be held liable.
Open two way discussion is great, but at some point the mark gets well and truly stepped over.
Reading on here and the other forums (fora?) certainly makes it interesting. I often think I get two completely different sides of the same story, and nobody is ever wrong. How can that happen?
It's amazing how a hobby that is supposed to give us all something in common - enjoyment of listening to music, can have such extreme reactions.
By the way, I only went over to communicate with Pinky after you pushed him off the naughty step. ;)
I'm sure I am not the only one reading the posts over there.
Anyway, it's time everybody chilled, and listened to some tunes. I'm about to spin Stanley Road vinyl and see if the newly arrived CuSat cables make much difference to my system.
Something I enjoy doing....
john dolan
17-04-2014, 18:31
I think all brands should show pictures of the internals of the kit they make.
If you make great kit put together with love and care id of thought they would be proud to show it off.
Gordon Steadman
17-04-2014, 18:31
Well, its a shame that this thread has drifted the way it has. I just hope Selby has gathered some useful information from it. There seems little doubt that he will have been put off NVA though which, if he could afford it, would be a shame from all (most) accounts.
Whatever, I'm going to move on and try and think some warm, loving thoughts about some favourite music and pretend all is well with the world.
I really don't care what it looks like inside. It's not something I will get to see often when listening to music.
If you guys want to, then "fill yer boots!"
I think all brands should show pictures of the internals of the kit they make.
If you make great kit put together with love and care id of thought they would be proud to show it off.
Hear hear, John!! That's my point exactly. Furthermore, they would also welcome feedback, positive or negative, from anyone in relation to the construction of whatever it is they've built.
Anyone who's got nothing to hide would feel that way.
Marco.
Gordon Steadman
17-04-2014, 18:42
I really don't care what it looks like inside. It's not something I will get to see often when listening to music.
If you guys want to, then "fill yer boots!"
Quite so. I just switch it on and listen to the music. Who gives a damn whats under the bonnet. Talking of which, I must dismantle the Audi tonight to check what the engine wiring looks like.
So much for loving thoughts:lol:
john dolan
17-04-2014, 18:46
khozmo passive shows internal pictures on all the sites that sell it because it looks very well made and the pics will help sell it.
Here is my passive
http://www.audiosynthesis.co.uk/passion.htm
scroll down it shows the internals it makes me wary of other kit that don't show the insides and don't like it when others take pictures of the internals of their kit.
My point is that the other forum, from what I have read talks about goings on here and elsewhere on similar forums.
That's a rather novel way of interpreting the content there, Kevin, but we'll leave it at that.
Some of the comments posted on here could be damaging to the livelihood of certain manufacturers, and in extreme cases, you, as the owner (if I am correct) of the forum could be held liable.
Please quote direct examples of anything written here that qualifies as such?
All I've done is express my opinion on the construction of an NVA preamp after I was shown a picture of its interior. How is that liable to damage anyone's livelihood? I've certainly written nothing even remotely libellous.
I certainly won't stifle expressing an honest opinion on a piece of equipment simply because what I've written is not in the manufacturer's best interests!!
Marco.
john dolan
17-04-2014, 18:57
Well if brands don't like it when people comment about the sloppy build of their products they shouldn't make products with sloppy build should they.
khozmo passive shows internal pictures on all the sites that sell it because it looks very well made and the pics will help sell it.
Here is my passive
http://www.audiosynthesis.co.uk/passion.htm
scroll down it shows the internals it makes me wary of other kit that don't show the insides and don't like it when others take pictures of the internals of their kit.
Spot on, my friend! :thumbsup:
Marco.
Found on eBay: http://bit.ly/1qmaZ0X
Or website: http://www.khozmo.com
They look beautifully made.
Hi there,
I have heard one of these as someone I know is using one. It is very, very good. Excellent value for money too.
Strangely, considering the course that this thread has taken, I also own an NVA P90SA. This pre is also very, very good.
I haven't ever heard them in the same room or system, but if pushed I would probably say that they are both pretty transparent, but differ slightly in the way that they deliver music. Whether or not one is better than the other is hard to say and I imagine that it would be a matter of taste more than anything.
Regards,
Frank
Gordon Steadman
17-04-2014, 19:13
Spot on, my friend! :thumbsup:
Marco.
Hows the inside of your computer? How come you bought it without checking? Camera? Kettle? take the lining apart on your best suit??
I'm sorry but this is silly and is just trying to make a point.
Hi there,
I have heard one of these as someone I know is using one. It is very, very good. Excellent value for money too.
Strangely, considering the course that this thread has taken, I own an NVA P90SA. This pre is also very, very good.
I haven't ever heard them in the same room or system, but if pushed I would probably say that they are both pretty transparent, but differ slightly in the way that they deliver music. Whether or not one is better than the other is hard to say and I imagine that it would be a matter of taste more than anything.
Regards,
Frank
thank's thank's thanks
john dolan
17-04-2014, 19:16
Hows the inside of your computer? How come you bought it without checking? Camera? Kettle? take the lining apart on your best suit??
I'm sorry but this is silly and is just trying to make a point.
I built my own sli 780s water cooled
http://i59.tinypic.com/15y9r14.jpg
Gordon Steadman
17-04-2014, 19:19
I built my own sli 780s water cooled
http://i59.tinypic.com/15y9r14.jpg
very nice but will it run MacOs?
Might I also add that the khozmo, in reality, as opposed to in the photographs that are being viewed by everyone, does appear a tad DIY too.
Hows the inside of your computer? How come you bought it without checking? Camera? Kettle? take the lining apart on your best suit??
I'm sorry but this is silly and is just trying to make a point.
Yes, but this is a hi-fi forum, Gordon, so we critique hi-fi equipment - simples! Anyway, are you quite finished yet going round and round in circles when quite clearly we will never agree on this matter?
Is there any chance, folks, that having done the NVA thing to death we could revert now instead to the original thread topic? :)
Marco.
Might I also add that the khozmo, in reality, as opposed to in the photographs that are being viewed by everyone, does appear a tad DIY too.
Yes, but it costs £195, not £700!! ;)
Marco.
Gordon Steadman
17-04-2014, 19:27
Hi Selby,
Can I suggest you have a look at a Creek passive?? They come up on eBay occasionally. I use mine in front of my Firebottle OTL as I have been influenced by the designer of said amp to be a lazy git and sit in my chair to adjust the volume. It seems transparent to me and I can't hear when its in circuit.
I have no idea what's inside (sorry - couldn't help it):eyebrows:
Yes, but it costs £195, not £700!! ;)
Marco.
True, but IMO the NVA is a bit better or perhaps I should say 'preferable'.
Maybe tomorrow I will give my mate a call and see if he can bring his khozmo over at some point to compare the two in the same system.
gordon, you are a carpenter and i'm sure you appreciate it when a piece of furniture, a guitar, etc is nicely built so whats wrong with looking at the inside of an amp, computer, tv, kettle
john dolan
17-04-2014, 19:35
The Creek passive just has a cheap Alps blue inside
http://i57.tinypic.com/wujlnb.jpg
if you can DIY and can live without the remote control for volume you could make your own pot in a box with a Alps for £20
Figlet108
17-04-2014, 19:36
Right, the Stereo Coffee LDR has moved into the test rig:
https://lh4.googleusercontent.com/-2xuLl05OV98/U1Arp86phbI/AAAAAAAACT0/bbnHnrSbieo/w430-h645-no/2014-04-17+19.59.57.jpg
Good news is that the volume does indeed go up and down when you turn the pot :)
It does sound transparent and there's plenty of drive, although given the limitations of the test rig all we can really say at this stage is that it works and sounds so far so good...
Onto the main system...
I am forever amazed and shocked at the childish manner in which certain members across all the hifi forums behave. I'm a member on Saab forums, bicycle forums, cafe racer forums and cigar forums and they are all nothing but happy places. Places where people with a specific hobby can chat, learn, share knowledge and further enjoy their passion. However in hifi for some very strange reason there seems to be nothing but hatred and a lack of respect for fellow members.
Don't you all feel a little silly when you look at some of the posts you're making. We are meant to be grown ups, all sharing and enjoying our hobby not being like the nasty pathetic bully at school.
I truly hope that one day a line is drawn between whatever hatred there is on both sides of the fence. Like two boys fighting in their lunch break, isn't it time both sides said sorry, shook hands and instead of spending hours and hours writing silly nasty posts, instead started enjoying this hobby we apparently all enjoy.
In what I've just written I'm not focusing on specific users as I believe this is a serious issue across all the hifi forums.
Let's make a stand, stop the rot and please just start enjoying your hobby.
Gordon Steadman
17-04-2014, 19:42
gordon, you are a carpenter and i'm sure you appreciate it when a piece of furniture, a guitar, etc is nicely built so whats wrong with looking at the inside of an amp, computer, tv, kettle
I already covered this in an earlier post. Do you checkout the insides of your kettle?? I suppose someone must do it!
True, but IMO the NVA is a bit better or perhaps I should say 'preferable'.
Maybe tomorrow I will give my mate a call and see if he can bring his khozmo over at some point to compare the two in the same system.
That would be interesting and most informative. When it comes to aesthetics, what looks nice, well-built or 'home-made' is entirely subjective.
The point is that, to me, the Khosmo looks much nicer than the NVA, is finished in such a way that it looks like the manufacturer takes pride in his workmanship and cares not only about what is seen from the outside, but also what isn't, and that it contains what, IMO, is a comparable quality stepped attenuator to that used in the NVA - all in a package that costs £500 less!
Anyway, let's get back now to the original thread topic :)
Marco.
I already covered this in an earlier post. Do you checkout the insides of your kettle?? I suppose someone must do it!
Enough now, please!
Marco.
Gordon Steadman
17-04-2014, 19:47
Enough now, please!
Marco.
Seems a reasonable idea:cool:
Figlet108
17-04-2014, 19:50
To reach my own closure for the thread side-track we've suffered I just have this to say. I appreciate that any kind of criticism of NVA however fair and valid from anyone always attracts a similar pattern of responses more than any other brand and no doubt many nasty and hurtful things have been said elsewhere about anyone here who has voiced any criticism.
To all those people in particular, and everyone here as well I wish you all love and peace during this Easter. I don't know the purpose of life and creation, but it's certainly not about hate... I hope you all enjoy some precious time with you families.
Thank fuck for that. I should add that since there's now been more than enough written about the NVA preamp in question, any further mention of such will be removed without further warning.
Let's get the thread back on topic!
Marco.
To reach my own closure for the thread side-track we've suffered I just have this to say. I appreciate that any kind of criticism of NVA however fair and valid from anyone always attracts a similar pattern of responses more than any other brand and no doubt many nasty and hurtful things have been said elsewhere about anyone here who has voiced any criticism.
To all those people in particular, and everyone here as well I wish you all love and peace during this Easter. I don't know the purpose of life and creation, but it's certainly not about hate... I hope you all enjoy some precious time with you families.
:clap: :respect: Happy Easter one and all... ;)
let the bunnies dance !!:p
:clap: :respect: Happy Easter one and all... ;)
Eggsactly :eyebrows: (groan)
Right, the Stereo Coffee LDR has moved into the test rig:
https://lh4.googleusercontent.com/-2xuLl05OV98/U1Arp86phbI/AAAAAAAACT0/bbnHnrSbieo/w430-h645-no/2014-04-17+19.59.57.jpg
Good news is that the volume does indeed go up and down when you turn the pot :)
It does sound transparent and there's plenty of drive, although given the limitations of the test rig all we can really say at this stage is that it works and sounds so far so good...
Onto the main system...
thats great !! i'm really looking forward to your impressions .. best
:-)
Thank fuck for that. I should add that since there's now been more than enough written about the NVA preamp in question, any further mention of such will be removed without further warning.
Let's get the thread back on topic!
Marco.
Regarding passive preamps, and looking at Naim neatness in wiring in particular, do we think that tightly bundled wires are preferable to looser wiring and proper angles to prevent crosstalk? Does the 'neatness' of a passive preamp reflect the quality of sound? More important is the wiring arrangement and quality of soldering, shortness of signal paths etc. IMO.
Why are we looking at a picture and equating it to HiFi? As you say Marco 'your ears' are the final arbiter certainly not your eyes.
Mr Kipling
17-04-2014, 20:14
An amplifier designer of any merit should always strive to achieve the highest possible standards of construction within the available budget, inside and out of their equipment, whether something impacts directly on sound quality or not.
Marco.
What if their objective is purely to try to achieve the highest level of sound quality possible?
john dolan
17-04-2014, 20:14
Regarding passive preamps, and looking at Naim neatness in wiring in particular, do we think that tightly bundled wires are preferable to looser wiring and proper angles to prevent crosstalk? Does the 'neatness' of a passive preamp reflect the quality of sound? More important is the wiring arrangement and quality of soldering, shortness of signal paths etc. IMO.
Why are we looking at a picture and equating it to HiFi? As you say Marco 'your ears' are the final arbiter certainly not your eyes.
With passive preamps the quality of the attenuator and selector switch are the most important things imo.
With passive preamps the quality of the attenuator and selector switch are the most important things imo.
Yes and some would have noticed the Elma switches and Shinkoh resistors from photos in this thread, so definitely agree. Surprising how much different a switch or pot makes though.
Figlet108
17-04-2014, 21:04
Ok, Stereo coffee LDR in the main system now:
https://lh3.googleusercontent.com/-psExYgIVVY8/U1A8diWrlOI/AAAAAAAACUI/qVr-OQBFrmI/w968-h645-no/2014-04-17+21.09.16_resize.jpg
Obviously it's early days and this is not in comparison to any other pre, just a comparison to no pre at all. Also just listening subjectively for now, nothing objective or scientific here.
On the positive side it seems very transparent, no doubt about it and there's no sign of compromise to drive or dynamics. Imaging also good.
On the negative side (apart from terrible casing and cable work ;) ) there is still clearly audible sound even when the volume is at 0. And then when the volume control is turned there's very little increase in volume initially and then suddenly it jumps up in volume.
There's a good chance I've cocked something up - anyone have any idea?
What are the two black boxes at the bottom?
Figlet108
17-04-2014, 21:21
The one on the left is a Pardo PSU for the Young DAC. The one on the right is the PC I designed and built after the TFS.
hmm, nice .. ask chris here http://www.ebay.com/itm/Light-Dependant-Resistor-Single-input-Preamp-Kit-/301150377536?pt=AU_Electronics_Audio_Amplifiers&hash=item461df61640
The Rigol DC power supply you have do you use that just for building/testing or as a perm power supply, it's one hell of a unit.
Figlet108
17-04-2014, 21:55
Yes the Rigol is just a programable bench PSU for building and testing electronics projects. It's waaaay over the top for my abilities, but it makes me feel like a real man whenever I use it :)
Figlet108
17-04-2014, 21:58
Hey Macca, it looks like from this thread that it is the same stereo coffee LDR you have after all:
http://theartofsound.net/forum/showthread.php?28220-LDR-Preamp-Single-and-3-Input-Kit&p=488227#post488227
Regarding passive preamps, and looking at Naim neatness in wiring in particular, do we think that tightly bundled wires are preferable to looser wiring and proper angles to prevent crosstalk? Does the 'neatness' of a passive preamp reflect the quality of sound? More important is the wiring arrangement and quality of soldering, shortness of signal paths etc. IMO.
Why are we looking at a picture and equating it to HiFi? As you say Marco 'your ears' are the final arbiter certainly not your eyes.
We're kind of going around in circles here, Neil. I will always choose equipment that has been produced predominantly on optimising sound quality, but not at the expense of feeling that the manufacturer concerned doesn't care equally as passionately about the standard of his workmanship.
Perhaps that doesn't bother you, but it does me. It's not just about your eyes or ears being the arbiter; it's about what's in your heart, too!
Marco.
Perhaps that doesn't bother you, but it does me. It's not just about your eyes or ears being the arbiter; it's about what's in your heart, too!
Marco.
That makes a change from you worrying what is in yer gusset, big boy :eyebrows:
What if their objective is purely to try to achieve the highest level of sound quality possible?
That's fine, if that approach suits the customers of the product concerned. However, those who think differently are perfectly entitled to express their opposite view when seeing pictures of a product that goes against their particular ideals.
Personally, I don't think there's any excuse for a manufacturer not to build a product to the best of his or her ability, in terms of both construction and performance, and happily most of them do! :)
Marco.
That makes a change from you worrying what is in yer gusset, big boy :eyebrows:
Hehehe...ya knows me too well! :D
Marco.
Figlet108
17-04-2014, 23:00
hmm, nice .. ask chris here http://www.ebay.com/itm/Light-Dependant-Resistor-Single-input-Preamp-Kit-/301150377536?pt=AU_Electronics_Audio_Amplifiers&hash=item461df61640
Yep, just exchanged emails with Chris. He's going to send me the latest board and new 500k pot.
Excellent customer service and very pleasant to deal with - couldn't ask for more.
Mr Kipling
17-04-2014, 23:10
Personally, I don't think there's any excuse for a manufacturer not to build a product to the best of his or her ability, in terms of both construction and performance, and happily most of them do! :)
Marco.
Well, at times, life isn't always that straightforward - ask Stan Curtis,, not exactly someone ignorant in the field of audio design. Working on the Cambridge Audio P50 MK II with its wiring loom and it's "rat's nest" of wires produced a sound that wasn't equalled by the production units with their neatly bundled looms which the production manager insisted on, which had SC somewhat frustrated.
Figlet108
18-04-2014, 15:39
Ok, Stereo coffee LDR in the main system now:
https://lh3.googleusercontent.com/-psExYgIVVY8/U1A8diWrlOI/AAAAAAAACUI/qVr-OQBFrmI/w968-h645-no/2014-04-17+21.09.16_resize.jpg
Obviously it's early days and this is not in comparison to any other pre, just a comparison to no pre at all. Also just listening subjectively for now, nothing objective or scientific here.
On the positive side it seems very transparent, no doubt about it and there's no sign of compromise to drive or dynamics. Imaging also good.
On the negative side (apart from terrible casing and cable work ;) ) there is still clearly audible sound even when the volume is at 0. And then when the volume control is turned there's very little increase in volume initially and then suddenly it jumps up in volume.
There's a good chance I've cocked something up - anyone have any idea?
Ok, I'm quite embarrassed to have to admit to my stupidity: I connected the inputs and outputs the wrong way round! :doh: :o
Fair play to the LDR circuit as it still worked just fine apart from the 2 minor issues I mentioned.
And a big thanks to Chris Daly for being so responsive and helpful :clapclapclap:
Anyway, it's all working perfectly now and I've been listening all day (since the wife is out).
It sounds superb. I can't tell the difference between having it in the system and not, so can't ask for more.
For £70 (delivered) for single input + say £30 for a small case + £2 for a PSU (http://www.ebay.co.uk/itm/New-UK-DC-12V-1A-Switching-Power-Supply-adapter-100-240V-AC-Promotion-/200874517470?pt=UK_Computing_Other_Computing_Netwo rking&hash=item2ec50de3de) I think it's a steal.
great news.. will you have to send the old board back when you get the updated one ?
I'd probably need the 3 input version. Are there any upgrades or things you can do to make it even better? PSU for example? Also how does this pre compare to the one I originally posted or any other pre people have such as Croft, Music First etc?
Hey Macca, it looks like from this thread that it is the same stereo coffee LDR you have after all:
http://theartofsound.net/forum/showthread.php?28220-LDR-Preamp-Single-and-3-Input-Kit&p=488227#post488227
That was last October! Time flies. Got to go in tomorrow see if there has been any progress.
Figlet108
20-04-2014, 10:57
great news.. will you have to send the old board back when you get the updated one ?
It's just the control board that is being sent, not the board with the LDRs on.
When you buy a Stereo Coffee LDR it looks like they will send you any later revisions of the Control board for free, which I think is pretty awesome.
Macca, I suggest you get in touch with Chris and request the latest control board too.
Figlet108
20-04-2014, 11:04
I'd probably need the 3 input version. Are there any upgrades or things you can do to make it even better? PSU for example? Also how does this pre compare to the one I originally posted or any other pre people have such as Croft, Music First etc?
The 3 input is £100 + case + PSU, so still very good value.
No idea what difference a good linear PSU would do for this particular circuit... I suspect the biggest difference would be the positive consequence of not introducing a cheap switching supply into the general system...
As for comparisons I only have 1 other pre at home I can compare to and yes, you've guessed it, it's an NVA. It's a P50 I've had in the attic for years. I've been listening and comparing both for the past 2 days and I'm going to post my thoughts a bit later today. Hopefully the NVA KGB won't get dispatched this time to silence or discredit me if I say something they don't like... :)
. Hopefully the NVA KGB won't get dispatched this time to silence or discredit me if I say something they don't like... :)
Good luck with that ;)
Have to say I am a bit confused by the need for a PSU as I was under the impression that this is a passive device. Apparantly not. I'm not keen on using active pre-amps with gain since after many years of experimentation I suspect it is the reason why a lot of people do not rate red book CD as a source compared to vinyl.
Figlet108
20-04-2014, 12:16
Good luck with that ;)
Yep: "Full alert for all agents in the field - the Dictatorship is under threat!" :D
Have to say I am a bit confused by the need for a PSU as I was under the impression that this is a passive device. Apparantly not. I'm not keen on using active pre-amps with gain since after many years of experimentation I suspect it is the reason why a lot of people do not rate red book CD as a source compared to vinyl.
The attenuation is passive. The PSU is only used to power the LEDs in the LDRs. As the pot is turned it reduces or increases the brightness of the LEDs and thus the resistance within the LDRs changes and causes the attenuation (http://en.wikipedia.org/wiki/Photoresistor).
That's why I'm not sure how a fancy PSU could effect the LDR circuit at all.
Thanks Jason. It's all coming back to me now.
The Barbarian
20-04-2014, 12:22
I'd have thought the best passive to use would be one that used a pair of high quality single channel Linear pots with charcroft Z Foil as LFR.. anyone could knock one of these up..
docfoster
20-04-2014, 13:01
The 3 input is £100 + case + PSU, so still very good value.
No idea what difference a good linear PSU would do for this particular circuit... I suspect the biggest difference would be the positive consequence of not introducing a cheap switching supply into the general system...
As for comparisons I only have 1 other pre at home I can compare to and yes, you've guessed it, it's an NVA. It's a P50 I've had in the attic for years. I've been listening and comparing both for the past 2 days and I'm going to post my thoughts a bit later today. Hopefully the NVA KGB won't get dispatched this time to silence or discredit me if I say something they don't like... :)
Ahoihoi Mr. S! How the devil are you...?
:-)
Just caught up with your LDR exploits here. It looks like my usual plan of waiting for someone with known similar kit and ears to my own to do all the leg work and then simply copy them will be once again unrolled. (The parchment is somewhat tattered and yellowed these days...)
I watch with interest!
Figlet108
20-04-2014, 13:29
All good here Ben, thanks. And a Happy Easter to you and the family
I'm really liking how this LDR pre is sounding. Wife's been out most of yesterday and today so managed to get a load of man-music in which I don't often get a chance to listen to loud.
I'll write up a bit more later when I can be bothered, but you'd love the percussion that comes out of this thing now...
What would be even more interesting though (especially for you) would be to get Macca to pull his finger out (hint hint!) and get his LDR built in time for his bake off with Marco and the Khozmo pre and the P90SA.
Stratmangler
20-04-2014, 13:29
I'd have thought the best passive to use would be one that used a pair of high quality single channel Linear pots with charcroft Z Foil as LFR.. anyone could knock one of these up..
Not linear - they give you far too much signal at an earlier point in the turn of the pot.
Log pots would give better adjustability.
RdfIZEB2rdM
docfoster
20-04-2014, 13:35
All good here Ben, thanks. And a Happy Easter to you and the family
I'm really liking how this LDR pre is sounding. Wife's been out most of yesterday and today so managed to get a load of man-music in which I don't often get a chance to listen to loud.
I'll write up a bit more later when I can be bothered, but you'd love the percussion that comes out of this thing now...
What would be even more interesting though (especially for you) would be to get Macca to pull his finger out (hint hint!) and get his LDR built in time for his bake off with Marco and the Khozmo pre and the P90SA.
All opinions gratefully received...
Thanks for the seasons greetings...! All the best to you and yours.
"Man music"... I have a mental picture of you stripped to the waist, working up a sweat to some awkward medley of Motorhead, NWA and Wagner or something...
What would be even more interesting though (especially for you) would be to get Macca to pull his finger out (hint hint!) and get his LDR built in time for his bake off with Marco and the Khozmo pre and the P90SA.
When I ordered it I did think that I could build it myself until I got it and looked at the instructions at which point I immediately farmed out the job to a local EE and am still waiting six months on. It will get done, I promise :)
The Barbarian
20-04-2014, 13:43
Not linear - they give you far too much signal at an earlier point in the turn of the pot.
Log pots would give better adjustability
The LFR will decide that.
Stratmangler
20-04-2014, 13:55
The LFR will decide that.
Must admit I hadn't considered the Z foil ....
The Barbarian
20-04-2014, 15:16
The resistor value creates the curve.. Just work out the required resistor, wire it between the output & Ground pins & bobs yer uncle a more accurate pot..
There's a thread on AT about LDRs they appear to be not especially well matched (drifting over time) and not very linear in their operation...
Figlet108
20-04-2014, 17:47
Hi Neal, do you mean this thread (http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=4915&highlight=ldr)?
Interesting read.
So far mine are well balanced (certainly to my ears), but only time will tell if they start to drift.
No complaints so far and sounding very clean and transparent.
I'd have thought the best passive to use would be one that used a pair of high quality single channel Linear pots with charcroft Z Foil as LFR.. anyone could knock one of these up..
What does LFR stand for and, if I'm still none-the-wiser, how does it work?
The Barbarian
20-04-2014, 18:47
Law Faking Resistor It allows you to immitate the curve of a Log pot while using a more accurate Linear pot.
I'm not keen on using active pre-amps with gain since after many years of experimentation I suspect it is the reason why a lot of people do not rate red book CD as a source compared to vinyl.
Lol - that's news to me! :eyebrows:
Marco [an active preamp owner, who enjoys CD and vinyl daily, in equal measure].
There's a thread on AT about LDRs they appear to be not especially well matched (drifting over time) and not very linear in their operation...
i'm not sure but i think that it is possible to control each LDR with software. See the link... i would appreciate an expert opinion as i'm not sure i understood it completely.. thank's
http://www.tortugaaudio.com/hiz-controlsoftware-improves-ldr-passive-preamps/
Light Dependant Resistor
20-04-2014, 22:21
i'm not sure but i think that it is possible to control each LDR with software. See the link... i would appreciate an expert opinion as i'm not sure i understood it completely.. thank's
http://www.tortugaaudio.com/hiz-controlsoftware-improves-ldr-passive-preamps/
In our opinion, its much better to take time matching the LDR's in the first place. We use the NSL32SR2S which suits applications using matched devices. A set of LDR's we put together 4 years ago measures the same today, and we expect it will continue to do so for 20 or more years.
In our opinion allowing software to control LDR's invites more errors, and we consider is sure to detract from the excellent audio that is possible. The two forum members who are our customers will receive an update board shortly, which should remove any doubt as to the capabilities of our Stereo Coffee LDR. We are also building a unit for the bake-off.
Cheers / Chris
Light Dependant Resistor
21-04-2014, 01:38
Relieving some of the mystery concerning matching of LDR's Firstly the NSL32SR2S is a very good part. We buy in lots of 50. Our test set up is our control board ( as there is nothing better ) fed from a 12v regulated supply. We feed the control board out into a T arrangement the left side ( similar to a pot but fixed ) is 54k resistance the right 250k resistance, with this we have a circuit that doesn't change and is easier to assess LDR's.
We firstly set up the shunts ideally these should be LDR's exhibiting with our test rig a pair exhibiting 2.5k resistance, rather than initially solder parts in we place the LDR in the circuit board, and find two that match well at 2.5k, about 3.4k is our cutoff point as these then are a bit weak for the task of doing the shunts, if the first dips lower when the second is ramping up we try another as these two just won't work, slowly but surely a match starts to occur by patiently sorting. We make the shunts as close as possible as we do not want L/R imbalance having to be corrected in the series, and if there is a small imbalance we then permit the series to be just slightly out the opposite way to the shunts, so as an aggregate the 2 pairs then match.
Next the series pair and these can take considerable time to match, but with patience you then similarly get good match with them too, and so on to the next input series pair. So really its just time and care to provide our customers with the best possible match of LDR that provides very good stereo separation, typically better than commercially available products.
Cheers / Chris
Lol - that's news to me! :eyebrows:
Marco [an active preamp owner, who enjoys CD and vinyl daily, in equal measure].
It's news to you that a lot of people do not rate red book CD? Do you ever read hi-fi forums, Marco? :) I am sure you get great results, but a lot of people don't. Part of a wider question that really should be a separate thread - I may start it later on.
It's news to you that a lot of people do not rate red book CD? Do you ever read hi-fi forums, Marco? :)
Lol - no, it's news to me that active preamps are responsible for the problem! I think it's about time you heard a decent active preamp with a CD player of your choice (then you wouldn't make comments like that) ;)
Marco.
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