View Full Version : The Birth and Evolution of a Phono Stage.
Ok... This all started because I need a phono stage and I've been doing a bit of waffling about it recently received some suggestions, one of which I've taken as a bit of a challenge. So here goes....
The Plan:
To try and demonstrate that with a bit of basic knowledge and asking some questions it's possible to build a good quality phono stage for not a lot of money. In this case, no more than £200, hopefully considerably less.
Wherever possible everything will be sourced via t'internet or re-cycled from stuff that's lying around. All questions/answers will come via this forum to show the value of the on-line community.
--------------------------
So, here we go. Feel free to ask questions, offer advice, pour scorn and mockery etc. over the next few weeks and we'll see what happens!
Cheers,
Mike.
P.S.There may not be much happening today as one of our cat's has died and we've just had to bury him, so I'm not really in the mood. :(
P.S.There may not be much happening today as one of our cat's has died and we've just had to bury him, so I'm not really in the mood. :(
That is serious shit man :( you have my sympathy.
I lub my pooky (who dat!) and he is getting old. I have always had cats I hate it that they die. Dogs - huh! - horrible smelly things. Cats, so much internal energy and comunication. They are little people, you just need to learn the language.
Mike Reed
29-03-2008, 18:17
As the owner and worshipper of a stereo pair of monoblock cats (in black, of course) (monoblAck?), you have my sympathy. You don't say what the cause of death was, but if old age, consider the life you gave him (or her).
The father cat of mine loves to sit between the speakers for hours; you can see his ears twitching. He does prefer rock 'n roll to classical; the beatier the better.
His son has no interest in music at all. Kids nowadays......!
Never a dull moment with moggies; one of Nature's most successful species.
Agreed - and very well put, Richard. Sorry to hear about your cat, Mikey :(
We have three 'moggies' - two of them are 16 going on 17, and one is 11, so you have my sympathies.
Maybe your phono stage project will help take your mind off it? :)
Marco.
anthonyTD
29-03-2008, 19:38
Agreed - and very well put, Richard. Sorry to hear about your cat, Mikey :(
We have three 'moggies' - two of them are 16 going on 17, and one is 11, so you have my sympathies.
Maybe your phono stage project will help take your mind off it? :)
Marco.
hi mike,
my sympathy too mate, although it has been said that most who have commented have cats, or prefer cats, i remember my old colly cross dog, he was 17 when i had to eventually agree to let him go, broke my heart, even as i write this, it still hurts like hell...although their gone, you never forget them...
anthony
Filterlab
29-03-2008, 20:38
Sorry to hear about your cat mate, they're great characters - oh the stories I could tell you about Smudge (my cat from years back), full of mystery and snigger inducing moments, that's cats.
Thanks for the sympathies guys, Gibson (bless him) is now buried under the Acer tree at the bottom of the garden next to Mouli (she was my fave cat), but we still have some critters left, so life goes on...
Lister - Gibson's brother is still going strong at 17 years young.
Ginny - the staffy, big daft girly dog.
Milo - the Leopard Gecko.
Idris - the Bearded Dragon - jeez he can move fast!
And a pond full of various fishy folk, who are accompanied at the moment by monumental amounts of frog spawn and humping frogs!
More phono stuff tomorrow.
http://img146.imageshack.us/img146/3274/p3301511ag7.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-03-30
It all starts with this, an NVA phono board and regulator.
There are a few mysteries to solve here, for starters the phono board has bee supplied with a few components deliberately missing, all part of the challenge you see!
But first things first. Non of this will do anything without a power supply so that's the first place to start, we'll be needing a transformer or perhaps four, in fact! The phono board has four gain stages (two per channel) each of which is capable of being powered separately, so I have a few of choices:
1. One PSU feeding all for 'stages'.
2. One PSU with four individual regulated outputs.
2. Four separate PSU's.
At he moment I leaning toward option 2 as reasonable balance between cost and performance, but I'll have to do a bit of pricing up first. At the moment the only clue about this PSU design is from Richard suggesting a 18-0-18 (or upward) transformer, I'll have to have a look at this regulator board and try to work out what I/P voltage it needs (after rectification and smoothing) and what it's O/P is.
Hmmmm, decisions, desisions.........
Cost so far: £100 exactly. Gulp, thats half the budget gone already!
:scratch:
Ok, A quick peek at the pair of TO220 reg chips tell's me they're LM317 (+37V) and LM 337 (-37V), so the 18-0-18 tranny is making some sense now.
A very eye straining squint at the op-amps on the phono board (hopefully) tell's me they're OP37G jobs, which want a supply of 22V.
Time to find a tranny and do some fiddling!
:)
P.S. in the interest of the 'finding everything on t'internet' promise, I looked it up on the RS website to make sure. I recognised the reg's but I'm clueless with op-amps! :confused:
By the way....... when I've finished poncing about with all this solid state stuff I'm still going to build a valve one.
So there! :ner:
LOL. Nice one, Mike.
Keep us posted of developments. Hopefully, your 'mentor' will be around to provide any necessary guidance ;)
Marco.
Mike, you could have got a Project Phono for about £55! :lolsign:
Also WAD had a neat little DIY chip based phono stage that works very well. You could easily put one together for under £50, I'll post the cct if you like...
Yeah!..... I know! :steam:
But a challenge has been made and I've bitten! :mental:
Now that I've got the boards I reckon I could have done something very similar for less than a tenner! :mental: :mental:
Oh well!
Ok.....
The supplier of the boards above has been somewhat offended by various comments and sent me a 'concise and to the point' PM and 'requested' that I return them. Which I am going to do!
Plan B then, (there is also a plan C and D waiting in the wings) so, watch this space.....
Cost so far: £zero.
Hmmm, this could take a while! :scratch:
Richard needs to get a grip. He's behaving like spoilt child! :mental:
Keep us 'in the loop' with your phono stage - sounds intriguing... :)
Marco.
Right...
Forget about Plans B & C!
I'm going straight for Plan D. I can't be bothered messing about with this sand amp stuff.... I can't find a schematic or kit that I actually like to look of.
So it's straight in at the deep end with a valve job, It'll be my first scratch build so bear with me, it could take while.
If it goes completely quiet for too long someone give me a nudge, I may be dead!
:oops:
Prince of Darkness
02-04-2008, 21:49
Any particular circuit lined up?
Top of the list would be a p-2-p wired Phono2 or Phono3 (& PSU) clone. Just need to source a suitable tranny first.
:scratch:
Has your Goldring arrived yet, Mikey?
If so you're half way there! ;)
Marco.
No, I cancelled it. I thought I'd wait a little while longer till I can afford something a little more upmarket. Maybe that AT you mentioned, we'll see.
Cheers.
Way hey... Result! :cool:
Go for the AT33PTG - it's a no brainer, mate. Trust the Marco-boy. I knows me cartridges ;)
Marco.
Filterlab
03-04-2008, 08:30
I'll second that, Marco is very good indeed with anything turntable related. :)
The cartridge can wait a while....
I'm looking for a transformer for the PSU at the moment, I want something with 240V primary and 270-275V secondary. Anyone got any ideas?
:scratch:
Sorry, mate, you need a techie-type for that one.
Going back to your cartridge (for a second) if you fancy sticking to am MM instead of a coil, then I would recommend any of the Nagaokas shown here on the Musonic Styli site:
http://www.musonic.co.uk/
Click on 'Cartridges', then 'Nagaoka'.
Some of the more exotic ones there are really fab :smoking:
Marco.
Right, I've had enough of waiting for transformer manufacturers to 'get back to me'! (I was thinking).
When rather fortuitously, an email arrived yesterday with some interesting schematics attached. One of which is an intriguing take on the PSU I was thinking about making which uses a pair of 240:9V traffo's back to back, all the components seem to be easily obtainable 'off the shelf' items so there should at least be some progress shortly! :)
There is a name on the corner of this schematic, to whom I may be addressing some questions. ;) Take a bow Mr Nick Gorham!
Cheers,
Mike.
Here's the schematic for the PSU:
http://img256.imageshack.us/img256/4880/phono1gg2.gif
By Shian7 (http://profile.imageshack.us/user/Shian7) at 2008-04-12
Time to start buying some bits at last! :)
Thats most of the parts now ordered!
I just need the choke and tubes, and I'm away!
Oh!..and a box!
;)
Maplin doesn't supply the choke any more, but the same one can be found here
http://www.livinginthepast.demon.co.uk/xformer.html?amplifiers_summary.html
http://img144.imageshack.us/img144/548/phono1apw6.gif (http://imageshack.us)
By Shian7 (http://profile.imageshack.us/user/Shian7)
Do I need the bit in the red box I wonder....... What's it for?
:scratch:
Its a C4S constant current source, it has two jobs. It isolates the supply from the rest of the phono stage by looking like a very high impedance to AC, and it provides a load for the VR regulators to work as shunts.
What phono stage do you intend to use after it? As if its the one I built that supply for, that also has CCSs in the first anode load, and you may have trouble finding the depletion mosfets I used in that position, so you may need to use two more C4Ss anyway.
Ooer!... I'd best leave it in there then! :exactly:
It's for more or less the same phono stage, a WD Phono3, or maybe a homebrew heavily based on it.
The parts are on yesterday's RS order anyway. Thanks for the info, a little bit more learnt! :)
Cheers,
Mike.
Ha!... 'stuff' has begun to arrive. Rah!!! :)
Progress soon!....
:smoking:
Pah!
'Stuff' is not arriving fast enough. Waiting is a pain in the @rse! :unfair:
Maplin doesn't supply the choke any more, but the same one can be found here
http://www.livinginthepast.demon.co.uk/xformer.html?amplifiers_summary.html
What a very nice man to deal with. Thanks for the link Nick! :)
Cheers,
Mike.
anthonyTD
22-04-2008, 20:22
Thats most of the parts now ordered!
I just need the choke and tubes, and I'm away!
Oh!..and a box!
;)
mike,
let me know what tubes your short of, i will donate them, [for the cause]
and anything else your short of, let me know, if i have it, its yours.
anthony...
by the way, you have a message,;):)
You have a PM too! :)
I'm sorted for the PSU (except for a nice box) but I've only just started looking at the phono stage itself. Can I email the schematic for a bit of advice maybe? ;)
Cheers,
Mike.
anthonyTD
22-04-2008, 20:44
You have a PM too! :)
I'm sorted for the PSU (except for a nice box) but I've only just started looking at the phono stage itself. Can I email the schematic for a bit of advice maybe? ;)
Cheers,
Mike.
yes,thats fine mate...
PS, did you understand my message about your amp???:)
Assuming you mean the point you made about biasing and matched valves. Yes.
Next time its 'up on blocks' I'll check it out. Theres a complete rewire on the cards in the not too distant future, and the 88's will be due for replacement before too long also.
As for the phono stage, I'll very soon be looking for a trio of ECC83's. To my mind it won't be too important that the tubes are matched to each other, but pretty much essential that each is very closely balanced internally. I'll email the schematics and you can let me know what you think, if thats ok?
Cheers,
Mike.
anthonyTD
22-04-2008, 21:26
Assuming you mean the point you made about biasing and matched valves. Yes.
Next time its 'up on blocks' I'll check it out. Theres a complete rewire on the cards in the not too distant future, and the 88's will be due for replacement before too long also.
As for the phono stage, I'll very soon be looking for a trio of ECC83's. To my mind it won't be too important that the tubes are matched to each other, but pretty much essential that each is very closely balanced internally. I'll email the schematics and you can let me know what you think, if thats ok?
Cheers,
Mike.
yes, fine mate,:)
<*yawn*>...... Here's where I'm at so far.
You can probably tell there's still a little work do. Ahem!
:scratch:
http://img171.imageshack.us/img171/8673/p4271561di8.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-04-27
I'm still waiting for a couple of caps and some boxes for it all to live in to turn up, but I've got enough stuff here to make a start. At last!
:)
Having seen this thread I've some suggestions:
- we have a special (toroid) transformer, type 4N1193, been made for us for our line amp and phono pre amp. It has 2 x 200 V-0,1 A and 2 x 8 V-2,5 A. As an extra there's a static screen.
- In our designs we use a parallel stabilizer (shunt regulator), this can be an EL84 or a high voltage fet.
- We disagree with the use of an ECC83 anywhere in current audio designs. The internal capacity is far too high so bandwidth will be limited. Instead use a 6N1P.
Currently I've been busy on a "solid state" phono amp. If anyone is interested I could publish the design ideas in a new thread.
John
Filterlab
24-05-2008, 09:41
Currently I've been busy on a "solid state" phono amp. If anyone is interested I could publish the design ideas in a new thread.
John
Hey John! Post it up mate, we'd love to see your ideas. :)
Hi John,
Thanks for the suggestions, unfortunately I've already bought all the parts I need for this build but I'll keep them in mind for the next project.
The PSU is well under way as I type this, hope to get most of it finished today!
Cheers,
Mike.
Oops.... made a beginner's type cock-up with some diodes!
Doh! :doh:
Doubt it'll be finished today after all, got a nice curry and some alcohol abuse lined up. :mad:
Ha!.... Things are looking up!
Just scored these for £23.27 inc delivery. :)
They might not have enough gain for this job but I think they should be OK.
http://img524.imageshack.us/img524/9462/img0035bj7.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with Canon PowerShot G9 (http://profile.imageshack.us/camerabuy.php?model=Canon+PowerShot+G9&make=Canon) at 2008-05-26
Oops.... made a beginner's type cock-up with some diodes!
I suppose it's better than having a beginner's 'cock-up' with some dildos :lol:
Nice one on the valves :smoking:
Hey it looks like you might have this finished in time for Christmas... ;)
Marco.
Hey it looks like you might have this finished in time for Christmas... ;)
Marco.
Which Christmas would that be? :scratch:
Is 2008 somewhat optimistic?
Let's have a bet, then... Which do you think will come first - the completion of your phono stage or my Technics review? :eyebrows:
Marco
Christmas!!!.....
:lolsign:
I honestly do not know where the bloody time goes.......
There, I've done something at last.....:ner:
PSU board completed, need to build the case and connect up the rest of the gubbins now.
:)
http://img138.imageshack.us/img138/5163/p5261594yi7.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-05-26
Hmm... I need to make a decision. :scratch:
There is a PCB available for the actual phono part of this little project which would speed things up quite a bit, but it that cheating?
So what do I do? Carry on as planned with the point-point wired version, or 'cheat' and get it done quickly with the PCB?
Perhaps Marco or other passing admin could set up a poll?
Cheers,
Mike.
LOL. I don't think we need a poll for that, Mike. Start another thread here if necessary and target your query at people like Anthony, Nick (Lurcher), etc, who I’m sure will be able to help :)
Marco.
Well, if its the WD one you mean, the PCB makes life a lot simplier, and maybe for a first build would be worth it, hard wired has the potential to be better, but not by much, and there are other more important tweeks that could be done.
If you do build on PCB, it might be worth using pins for the coupling and output caps, so they can be changed later without running the risk of the PCB tracks lifting.
LOL. I don't think we need a poll for that, Mike. Start another thread here if necessary and target your query at people like Anthony, Nick (Lurcher), etc, who I’m sure will be able to help :)
Marco.
Just thought I'd try and get folk's opinions really Marco (and try and drum up a bit of interest!!!), but sod ya! I'd pretty much decided on the PCB option TBH. Like Nick says, makes life simpler.
And I want this thing up and running sooner rather than later.
It's not actually my first build Nick (well, it is for a phono stage) but I'm all for an easy life! ;)
Cheers,
Mike.
P.S. Can't help thinking I'd be better posting this stuff on the WD forum. Doesn't seem to be that many people here who really give a toss about DIY. Oh well! :confused:
P.S. Can't help thinking I'd be better posting this stuff on the WD forum. Doesn't seem to be that many people here who really give a toss about DIY.
I don't think that's the case. It's just that there are far more D.I.Y minded people on the WD forum (naturally) and of course also on audio talk, Nick's place. You might wish to post your query there, too :)
Marco.
You might wish to post your query there, too :)
Marco.
Nah!.... decision is made. PCB it is!
I'm the one who's going to be using it after all. :)
I'll save the point to point malarkey for the next project. ;)
Cheers,
Mike.
Ali Tait
28-05-2008, 18:08
Nick knows far more than me,but I'd give the same advice.PCB versus hard-wired sound difference will be minimal,and you'll effect a much greater difference changing components further down the line.
Using a "good" pcb design can be an advantage. On the PCB, by being very precious with the lay out of the traces, one can avoid unwanted oscillations. Also for an amateur it's almost impossible to make mistakes by false connections.
John
Yes!.....HaHa..... the final pieces of the puzzle have arrived!
Onward and upward!
:)
http://img80.imageshack.us/img80/4193/p5301596mc1.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-05-30
This looks like a very small pcb. What type of capacitors are intended for the RIAA correction?
John
This looks like a very small pcb. What type of capacitors are intended for the RIAA correction?
John
Hi John,
I'm using some 1% silvered mica caps for the RIAA section, they were the best tolerence I could find at the time I ordered them.
I'm also going to fit pcb pins in many places so that I can change components without wrecking the tracks.
Yes, the board is rather compact. ;)
Cheers,
Mike.
Argh!...... the pcb pins don't fit. :doh:
Bum!
Filterlab
31-05-2008, 11:17
Can you drill the holes larger, or is the illfittedness in some other capacity?
I could, but that would risk damaging the tracks. I'll just buy the right pins I think.
:)
Mica capacitors are okay. You better don't use pins. They make the signal path, the earthing and/or the supply lines longer and might lead into oscilations.
John
They make the signal path, the earthing and/or the supply lines longer and might lead into oscilations.
Not with ecc83's you won't. I would personally not bother with pins for the RIAA caps, I was thinking more of the coupling and output cap, they are the ones you are more likely to want to replace.
And another bit done:
http://img137.imageshack.us/img137/5377/p6011599bk0.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-06-01
Note unnecessary use of 3W resistors at the far end of the board.
Nothing special going on there, it's just that I already had them so put them to use rather than buying more lower wattage ones.
:)
Oh no, I'm at the scary part now, I need to make the boxes.
Eeek!
:sofa:
Can't wait to read your thoughts on the results of your labour, Mike! :)
Marco.
My thoughts at the moment are pretty simple: I am going to bleed! :(
Donald Hanson
04-06-2008, 17:27
The cartridge can wait a while....
I'm looking for a transformer for the PSU at the moment, I want something with 240V primary and 270-275V secondary. Anyone got any ideas?
:scratch:
Hi:
I know I am totally late for this party, but have you found your transformer yet?
If not, have you looked closely at the Hashimoto tube power supply transformers? A little pricey, very high quality (as one would expect from a former Sansui Electronics Engineer), but a fairly large lineup and you may find your power supply there.
http://www.tube-amps.net/
Hashimoto even has some mc step-ups that I may be doing in diy form this winter (providing of course that the schematic is available). Most of his stuff is there for the taking in schematic form. He just wants us to buy his transformers.
Hi Donald,
Thanks for the suggestion, but I've gone for a different PSU this time (schematic is in the thread somewhere). I've added that link to my favourites for future use though. Ta!
Cheers,
Mike.
Donald Hanson
04-06-2008, 17:49
Yeah, if I wasn't so lazy I would have read over the parts where this is all water under the bridge now. However, I am very eager to see the end result and to read your review of the product. Don't keep us in suspense too long eh?
Bum!..... someone pass me a 1mm drill bit please, I can't find mine. :(
'Stuff' is honestly happening, really, it is! :)
Right, I give up. I am clearly no carpenter! :(
I've had a few goes at building boxes/cases for this stuff and frankly they all look utterly crap! I might as well buy some! :doh:
Anyone got any links to places selling nice aluminium cases/chassis please?
Cheers,
Mike.
http://www.autocostruire.com/catalog/index.php?cPath=43&osCsid=514380e3c543dc44eeda398c40a38d3c
Is one I have used.
Thanks Nick, I've got that one but was hoping for something a little closer to home.
They look good quality though. :)
They are good value, and deliver in about a week.
Ooh!... that's not a bad delivery time considering they'd be comming from Italy.
What's the quality like? (he said, knowing damn well they'll be better than his half arsed woodwork efforts! :eyebrows:)
Cheers,
Mike.
Welll, they are not high end, the front panel is only 3mm (though thicker is available), the top and bottom benifits from a bit of damping, but for the price they are great. About the same (I would say) as the wad cases.
This is my pre in one of the cases, and a modified squeezebox in another
http://www.lurcher.org/nick/images/sbox/sb.jpg
Nick, Mike or anyone else, if you're ordering from this company around Sept/Oct this year I can collect stuff for you to save the carriage as Pistoia is not far from where my relatives live in Italy, whom I will be visiting.
Anyway, if I can be of any assistance just let me know :)
Marco.
I was hoping the boxes might arrive in time for this weekend so I could have everything finished, but according to the on-line tracking they are currently in Germany.
Oh well! :(
Getting closer. Now in the West Midlands. :)
Can you feel the excitement baby? :eyebrows:
Marco.
Not really.
They're bound to arrive when I'm on-call. :doh:
All work and no play makes Mikey... ;)
Marco.
Ha!... I have boxes!
They're actually very good for the price. I'm rather pleased with them. :)
Onward and upwards! Err, as soon as the weather gets a bit better that is. My garage is that full of crap it's completely impossible to work in there, I'll have to extract the tooling I need and do all the cutting & drilling on the patio. Humpf... :scratch:
Ooooh... 'On the patio', eh? Whilst one is sipping a glass of Claret, per chance? :eyebrows:
Marco.
Ooh!.. Ooh!.. Suits you sir!
Knowing you it'll sound better if you design it half pished! :lol:
Marco.
Prey tell!.... what makes you think I designed any of this? :lolsign:
Ok, you 'waved' a soldering iron in the rough direction of some mass-produced components.
Is that better? :lolsign:
Marco.
No it's not actually! :steam:
I'm very particular about 'how' and 'where' I poke my iron! :eyebrows:
Whilst one is sipping a glass of Claret.
mmMMmm... I quite fancy some actually, or a lovely Fitou. :)
Pity you're not here now. I have rather a fine collection of such specimens after our recent sojourn to France... :cheers:
Marco.
Well, I've got my 'marking out' done, but I'm on-call (again) so do I dare make a start, or am I tempting fate? :scratch:
Hell yeah!....
I'll be back later, probably bleeding a bit! :eyebrows:
I don't bloody believe it!
No sooner had I typed the post above... and yes, the phone rang! :doh:
Phew... false alarm. Excellent! :)
Laterz...
Filterlab
12-07-2008, 11:09
Tut, just phoned Mike and he hung up on me. :( He must be busy doing something.
Believe it or not, something constructive has actually happened! :)
I've got the PSU almost finished and late last night decided to to power it up and do some quick preliminary checks.
Heater voltage = 6.31V
HT = 320V (this was before the stabiliser (regulator) tubes were fitted)
AND!... nothing went BANG!.... so far, so good.
I'll get it finished shortly (with a bit of luck) and post some piccys and more details later on.
Cheers...
If you haven't electrocuted yourself I'll look forward to hearing more later :lolsign:
Marco.
Well it's going to be tomorrow now. Work intervened again. :doh:
Also, I've decided that the valves are going to be mounted on the top plates so a bit of reinforcing is in order. Both tops now have some 3mm aluminium plate clamped to the inside while the epoxy sets, I'll leave them overnight at least.
Oh, and I can't find any suitable connectors for the power umbilical at home. I'll see if there's anything at work that can be Wombled.
Wombled? Love it.
Let me know if you need those Mullards at some point, shweety :)
Marco.
Bah!... Why is it always the stupid little things that get in the way?
Here I am with everything I need to get it all finished, or so I thought, and can I find any screws and nuts to secure the valve sockets?
Screws, yes! Nuts?... err no! :doh: :steam:
More Wombling required......
How's the wombling doing, Mikey - are you any nearer to playing a record? ;)
Marco.
Wombling mission was a dismal failure! :(
However!..... A bit of 'getting the wallet out' action has procured the last of the necessary items! :)
Downside is I'm on-call tonight and tomorrow (of course... what else!) so I'm only managing to get bits & pieces done here and there.
The good news is, after tomorrow I've got a week (yes a whole week) including the weekend all to myself. Rah!!!
If it's not ready by the end of this weekend all forum members are invited round to my house to publicly kick me in the knackers!
Here's some piccys of the psu.
http://img253.imageshack.us/img253/9008/p7161688xs2.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-07-16
http://img253.imageshack.us/img253/8095/p7161690ij0.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-07-16
http://img253.imageshack.us/img253/3959/p7161689vq9.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-07-16
Looking good, Mikey :)
Nice big trannies, btw! It looks quite 'serious'.
Marco.
P.S Got your CD - cheers. Not had a chance to play with it yet. Will let you know what I think soon.
Cheers Marco,
No shoddy shite around here my boy! ;)
Just off to do a bit of testing, back in a bit. I hope! :scratch:
Ha!... It works! :)
Voltages are just a touch high but thats with no load so I'm not going to worry about that too much at the moment.
HT = 264V
Heater = 6.32V
http://img172.imageshack.us/img172/2125/p7161692pj2.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-07-16
Onto the phono stage itself now.....
I'm confident that my spuds will remain 'un-kicked'! :)
Good progress is being made. It WILL be finished by the end of this weekend! :eyebrows:
Oooh!..... I'm suffering today.
Had a lamb vindaloo last night, complete with CHILI garlic rice and a CHILI nan! My backside has definitely gone completely 'Johnny Cash' this morning, err, three times so far! :drugs:
Still!... It's not going to stop me getting this finished today. Oh no!
Piccys of glowing valves to follow later. :)
Would this be the appropriate time to use the phrase
'skittering aboot' ?
:lolsign:
Yes it would... Along with 'Ring of Fire'!
Oooh!..... I'm suffering today.
Had a lamb vindaloo last night, complete with CHILI garlic rice and a CHILI nan!
You dirty fucker! :lol:
I see I'm going to have to get Del to make one of her 'painfully hot' Vietnamese noodle soups when you arrive chez-moi... You're a real man if you can eat the whole bowl without being reduced to a crying, quivering wreck, gasping for air and drenched in pools of your own sweat :eyebrows:
Marco.
It's all done, built, finished!.... hahahahahahaha!!!
I'll test it n take piccys tomorrow. I'm knackered now and need a beer! :cool:
Nice one :clap:
Bet you test it PDQ after you've had that beer. The curiosity factor will be way too much... ;)
Let us know if it doesn't blow up! :lolsign:
Marco.
Bet you test it PDQ after you've had that beer. The curiosity factor will be way too much...
Generally beer and high voltage is a bad combination...
That combination won't be happening!
I'll play with it tomorrow.
Generally beer and high voltage is a bad combination...
Is that how you grew that quite impressive beard, Nick? :lolsign:
;)
Marco.
Not doing it was how it had time to grow :-).
Arrrgh!... there is a 'fault'! (meaning 'I've made a mistake'!) :(
Something's not right with the heaters. They come on quite brightly for a fraction of a second (surge?) then quickly settle down, but after about 30 seconds or so they fade away.
I've probably made a wiring mistake rather than fitted a faulty component so I'd better check that carefully first. The voices in my head are whispering "voltage regulator" for some reason.
Bum! :doh:
Nightmare, mate. These things happen with D.I.Y projects. I'm sure you'll fix it and if not there is plenty of expertise here from the likes of Nick, Anthony, John rtd, etc, which I'm sure will enable you to resolve the problem :)
Keep us posted.
Marco.
Hmmm.... The voltage regulator in the heater supply is overheating after a while (despite a big lump of aluminium stuck on it) and then the voltage collapses. Not a good sign. :(
What regulator are you using, what valves, and whats the voltage before the reg???
LM1085IT (5V, 3A).
3 random ECC83/12AX7
12.7V
I've moved the Reg to one of the chassis side plates (as a sink) and wired it back to the PCB, it seems much happier now. After an hour it's only warm and the heater voltage is a steady 6.29V
Some more piccys:
http://img501.imageshack.us/img501/3564/p7211693yi5.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-07-21
http://img501.imageshack.us/img501/2064/p7211694at5.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-07-21
LM1085IT (5V, 3A).
3 random ECC83/12AX7
12.7V
I've moved the Reg to one of the chassis side plates (as a sink) and wired it back to the PCB, it seems much happier now. After an hour it's only warm and the heater voltage is a steady 6.29V
If its any concelation, the WD one will overheat given a bit of prompting.
Just FYI, the problem is the high voltage before the regulator. you have 6.3 afterwards, 12.7v before, so there is 6.4v across the regulator, so at 0.9 amp (three ecc83's) the regulator is dissapating 6.4 * 0.9 watts or 5.75W, so it needs a heat sync that can dissapate that much heat while keeping the device within its safe limits.
Looking at the data sheets, I would estimate it would need a heat sync of at least 14 deg C per Watt.
Bolting to the case will do as well :-)
Anyway, does it work?
Prince of Darkness
21-07-2008, 15:47
If its any concelation, the WD one will overheat given a bit of prompting.
Yes, that's why WD bolted the regulator to the case on the psu III, whereas the psu II used a heatsink.:)
In this case, given there is 12 and a bit volts before the reg, and its producing 6.3v, and the regulator is a low drop out type that only needs 1.5v across it to regulate, you could afford to burn some volts before the regulator, adding a extra resistor and capacitor before the regulator would be a choice, a 1 ohm 7W wirewound and 10,000uf 16v cap would help.
Another thing to consider, is also using a resistor before the first cap, maybe a 0.5 ohm 7W would be worth trying. The point of that resistor is to reduce the size of the charging spikes into the first cap, and this may help to reduce switching noise.
Anyway, does it work?
Dunno yet. I'm throwing a TT together to find out right now.
It's connected up to my amp and theres some hiss and a bit of hum (nothing connected to phono stage i/p) which goes up and down with the volume. So I think it's doing something at least.
Anyway, does it work?
Well... Today I've fixed the overheating reg, I've converted my Hadcock from a 228 into a 242, rewired the armtube with Litz wire, mounted the cartridge and fitted the whole caboodle to the SL120. I've payed no attention at all to alignment other that checking the pivot to spindle distance.
And do you know what?
It works!!!! I'm playing vinyl again.... See Ya! :gig:
It works!!!! I'm playing vinyl again.... See Ya!
Nice one.
Let me guess the first record
What We Did On Our Holidays ?
:)
I thought the SL-120 was a gonner, dude... Where's yer DP-3000? :)
Marco.
Ali Tait
21-07-2008, 20:36
Nahh,
It's "I did it my waaaaay" :)
I thought the SL-120 was a gonner, dude...
Nah, it's still here at the moment, p/xing it for the DP this weekend.
First record was: Faithless - To All New Arrivals
LOL. I can see that's a favourite so I'm gonna have to play you it at mine... :)
And pray tell how did it sound?
Marco.
Err... pretty much as I expected it would; Brand New! :lolsign:
It'll take a little while yet, don't forget the cartridge is new and shiny too!
Only problem is a hum that gets obvious beyond half volume, but I've not even bothered looking at the earthing arrangement yet.
Shian, Whatever you do further I would advise you to replace that stabilizer for a new one. When you connected it the first time you saw a lot of light (glowing) from the tubes so there was a higher voltage there and that stabilizer went over the top. Don't trust it to stay functioning as it should. When replacing you could tage a LM78S05 or the µA7805c. Both types can handle 3 A with a maximum at the input of 35 Volts. The common pin should be connected to ground via two 1N4001 diodes in series.
There "was" ever a type called the 7806KC delivering 6 Volts but that one is out of production.
In our P-12 pre-amp we use that 78S05 (with the diodes) placed on the PCB with a small heat sink, but our DC input is around 11 Volt. At the input we have 10.000 µF and at the output 470 µF.
May be, if you follow up, the hum disappears. That's a "maybe" because hum might also originate from your way of earthing.
Anyway, I'm glad that with our kits this type of mishap cannot happen because all is on the PCB so the amateur is "forced" to do it the right way.
John
Shian, Whatever you do further I would advise you to replace that stabilizer for a new one. When you connected it the first time you saw a lot of light (glowing) from the tubes so there was a higher voltage there and that stabilizer went over the top. Don't trust it to stay functioning as it should. When replacing you could tage a LM78S05 or the µA7805c. Both types can handle 3 A with a maximum at the input of 35 Volts. The common pin should be connected to ground via two 1N4001 diodes in series.
There "was" ever a type called the 7806KC delivering 6 Volts but that one is out of production.
In our P-12 pre-amp we use that 78S05 (with the diodes) placed on the PCB with a small heat sink, but our DC input is around 11 Volt. At the input we have 10.000 µF and at the output 470 µF.
May be, if you follow up, the hum disappears. That's a "maybe" because hum might also originate from your way of earthing.
Anyway, I'm glad that with our kits this type of mishap cannot happen because all is on the PCB so the amateur is "forced" to do it the right way.
John
Unless I have misread the posts, I think the extra light was from the valve heaters at startup, which is often the case and they were built to do that. The power supply uses a CCS to feed the VR tubes, so its should not be possible to overdrive them as long as the CCS is set for 20ma or so.
Yep… it’s the heaters, they ‘light up’ quite brightly for a split second on start-up, as if it takes a moment for the reg to stabilise the voltage.
I’ll have a play around tonight when I get home to see if I can sort the slight hum, I’ll also have a rummage around and see what components I’ve got lurking here and there. See if I can burn off a bit of voltage before the reg.
Cheers…
as if it takes a moment for the reg to stabilise the voltage.
Its the way the valves are made. Some of the heater extends outside the ends of the cathode so heats up quicker than the rest of the heater that is enclosed.
Its nothing to do with a regulator problem, they would do the same with a bettery or AC.
I read somewhere it was a intentional design to reduce the switch on current inrush by getting some of the heater quickly up to temperature.
Interesting... another little nugget learnt. :)
I've never noticed it before TBH, certainly the single ECC83 in my WD88 doesn't exhibit this little trick, everything just gradually starts glowing.
Soft-start maybe? I thought that usually only applies to HT though?
Cheers...
Interesting... another little nugget learnt. :)
I've never noticed it before TBH, certainly the single ECC83 in my WD88 doesn't exhibit this little trick, everything just gradually starts glowing.
Soft-start maybe? I thought that usually only applies to HT though?
Cheers...
You tend to find it more on NOS valves, I don't think its been copied in newer production. I thik the goal is to avoid the thermal shock to the fillament. Certainly one of the main things that kill bright emitter directly heated triodes lieke the 211 and 845 is that everytime the fillament lights it gets a twist and shock, and each time it becomes a little bit more brittle. Eventually it will let go either in transport or at turnon. Unused ones are remarkably robust given the length of the fillament.
Right... onto another 'issue'. This may well be connected with the slight hum problem; I seem to have a potential difference between the two cases. The phono case being +42V with respect to the PSU case. Odd! :scratch:
Best get the lids off methinks.
Sounds like the case ground is connected to the heater supply somewhere. Thats about the voltage its raised by.
You need to make sure that the signal ground only meets the case at the one place you want it to.
Yep... that makes sense. I'll poke around when its cooled down.
I've tracked down the hum, it's not coming from the phono stage (at least not directly) but from the TT itself. There is no hum at all until I plug the motor unit into the mains. Having a lash-up of extension leads all over the place isn't helping.
Right... onto another 'issue'. This may well be connected with the slight hum problem; I seem to have a potential difference between the two cases. The phono case being +42V with respect to the PSU case.
Oops, that's wrong!
The phono case is -42V wrt the psu case. :scratch:
I am a silly silly man! :sorry:
Ignore the bollocks above about 42V between the cases, it was nothing more than a poor electrical contact with the front plate of the psu. :doh:
Ignore the bollocks above about 42V between the cases, it was nothing more than a poor electrical contact with the front plate of the psu.
Good, you have to watch out for the anodising, makes for a good insulator.
I did find one silly mistake on the input phono's while I was looking though. I'd connected them up to the step-up traffo's ok, but forgot to connect the 'outers' to ground. Ahem!... It's up and running again and sounding rather nice.
I'll get a few more miles on the clock before any more tinkering. :)
Been away at Steve's today doing a mini bake-off with my Sony transport and DAC, Croft preamp and Yaqin, and his Bel Canto, Spectral preamp and TD/AOS power amp - some interesting findings... :)
Anyway, glad your T/T set-up seems to be coming together nicely now. What's you initial impressions of the cartridge, Mike?
Marco.
What's you initial impressions of the cartridge, Mike?
Erm... early days but the midrange and treble are nice and sweet, bass is a bit weak(ish) at the moment. But not that weak, I have 'cone flap'! :eyebrows:
Setup is pretty rough 'n ready though, but I'm not going to mess about with it for now. Got to get the TT boxed up tonight to ship off to Dave at Green Home, I was going to go down and deliver/collect on Saturday but Cath is hijacking the car for the weekend.
There's another 'issue' I need to look into as well, the LED on the WD88 has decided it's a disco light when I play vinyl. That and the cone flap are a bit of a worry, they are in-sync. :scratch:
There's another 'issue' I need to look into as well, the LED on the WD88 has decided it's a disco light when I play vinyl. That and the cone flap are a bit of a worry, they are in-sync
Remember the gain of a phono stage is max at the low freq end. The phono stage has no rumble filter and the amp will be doing its best via feedback to reproduce the low fequency signal.
It would be possible to add a rumble filter, my I prefer Morgan Jones approach, fix the problem at source instead of trying to hide it later.
Might you have a problem with the resonant frequency of your arm/cart combination?
Might you have a problem with the resonant frequency of your arm/cart combination?
Indeed I might.
For now I'm not going to worry, the whole thing was more or less thrown together yesterday just to see if the phono stage works, which it does.
I'll spend more time and effort with setup when I install it on my replacement deck sometime next week.
To be continued....
There's still the problem of the "lighting up" of the valves when switching on. This has to do with the lower resistance of the filament when it's still cold (as in light bulbs). This means that at the start there will be more current flowing through the filament. The nice thing of voltage stabilizers though is that they have an internal current limit. So normally, when using such a stabilizer, there will be hardly any extra light from the tubes.
Overlooking the entire project with all the costs and labour I wouldn't hesitate a minute but replace those stabilizers and make sure the old ones are thrown away.
BTW We have this new P-14 pre-amp. That pre-amp doesn't produce any "noticeable" noise or hum whatsoever. But upon switching on my SL-1200, with a low output Van-denhul cartridge, I can hear hum originating from the motor. So this only happens when the TT is moving and can be heard with the ear inside the loudspeaker cones. At approx. 10 cm distance it's not noticeable any more.
It could be that your step-up transformer picks up the field from the drive motor. You can find out for sure by simply lengthening the signal cables and moving the pre amp to a greater distance from the TT.
John
There's still the problem of the "lighting up" of the valves when switching on. This has to do with the lower resistance of the filament when it's still cold (as in light bulbs). This means that at the start there will be more current flowing through the filament. The nice thing of voltage stabilizers though is that they have an internal current limit. So normally, when using such a stabilizer, there will be hardly any extra light from the tubes.
Overlooking the entire project with all the costs and labour I wouldn't hesitate a minute but replace those stabilizers and make sure the old ones are thrown away.
Ok, I am going to have one last try at this, then I give up
http://www.audioasylum.com/cgi/t.mpl?f=tubes&m=210090
Yep John,
"Lighting Up"
This is what they do. This is expected. This is design intended. It is not a problem. For some people it is a new and educational experience and it also needs to be so for you. There is no issue here. These valves perform this way by design. Nothing is wrong. It's about getting used to a new and unexpected presentation at fire up. Many of us have been there and understand it. Hook onto the end of our trail.
Best wishes,
Greg :)
Hi Greg :wave:
I'd never noticed it before (there's a Mullard CV4004 in my WD88) so I 'asked'. I'm happy with the explanation that Nick gave. :)
Cheers.....
Mikey,
How's this phono stage of yours doing then? You've been awfully quiet... :confused:
And what about the DP3000? Has it arrived? If so, how does it sound?
We need info!! :)
Marco.
I'm waiting for the DP to arrive, hence the silence. I've nothing to connect to the phono stage!
Christ, what is it on - the slow boat from China? ;)
I thought the deal was done over a week ago!
Marco
Well it's here!
First problem, it's a big fella and I need a bigger top for my stand! :scratch:
Second, I need a proper mounting plate (ordered) for the Hadcock, coz it's too nice a deck to make a bodge of it! :)
Nice one, Mike. I'm sure you'll get it sorted.
I presume the big fella is coming to Chester.....and the turntable, too ;)
:lolsign:
Marco.
Yes I could bring it along if anyone's interested.
Well I am most definitely. It will add to the list of excellent T/Ts coming, Nick's SP10, my KAB 1210, etc... :)
That's if it's in a playable state by then ;)
Marco.
That's if it's in a playable state by then ;)
Marco.
Indeed!...
And also if it's any good! :eyebrows:
I'm sure it will be. So is the phono stage 'sorted' now and sounding shweeeet :cool:?
Marco.
Not realy, it's only had a couple of hours or so in use. It needs burning in.
Nae hums now or any of that pish? :)
Marco.
Nah... the hum was getting induced from the TT motor unit, a bit of fiddling with the earth cable arrangement and equipment positioning sorted that out.
I'll have to watch out for that arm resonance/cone flap thing though. It could be that the tubing I've used to extend it to a 242 isn't suitable, in which case it'll go back to a 228. We'll see.
Cheers...
I think that's probably what it is, Mike. You might also want to consider getting one of Thruno's nicely machined plates made to go between your AT cartridge and the headshell on the Hadcock.
I reckon a little bit more mass there would be a good thing. The headshell on your arm is designed mainly for a high compliance moving magnet cartridge. MCs, in my experience, like a bit more 'girth', just like the ladies :eyebrows:
It's a shame George Hadcock is no longer alive. When I had my 242 Integra we used to have some good chats on the phone about how best to set-up his arms, and this and that. He was a true gentleman - pure 'old school'.
Marco.
I'll have to wait for the adaptor plate before I can find out what the problem is.
It's an interesting deck though, some nice bit's some not so, I might start a new thread about it when I get started. I can already tell it's crying out for a better plinth! :eyebrows:
Grrrr.... I'm getting impatient!
I hate waiting for 'things' to arrive. :steam:
If the adaptor plate doesn't arrive tomorrow I' going to have to bodge the arm on somehow.
I hear Sellotape works well...
Marco.
Arrrgh!.... The postman has been and brought me nothing but a letter from the criminal justice system, which does not help my Hadcock. :unfair:
Let the bodging commence! :mad:
Well... that's interesting!
I've removed a Mullard ECC83 from the phono stage to send to Jerry, and just filled the empty slot with a Brimar. The 'cone flap' is suddenly horrendous! :uhho:
The interesting thing is; the TT isn't even turned on, never mind playing a record!!!
I rather think I've been barking up the wrong tree by giving the Hadcock a good talking too! :scratch:
I think I need some 'known good' valves!
Good, I would check the power rails to make sure they are stable.
I've noticed that one particular Brimar sends it bonkers!
So I thought I'd try the 5751's I bought recently. I've popped the 5751's in and it's all but gone, if I turn the volume right up to max there's the odd twitch from the bass cones, but that's it! Just some hiss.
And boy does it sound good! http://www.wduk.worldomain.net/forum/images/smilies/biggrin.gif Just played 'Wish You Were Here' and was compelled to pick up the geetar and play along, then I got shouted at for "being too loud"!!! http://www.wduk.worldomain.net/forum/images/smilies/biggrin.gifhttp://www.wduk.worldomain.net/forum/images/smilies/biggrin.gif
When I get chance I'll put the old tubes back in and take a vid of the cones, too busy playing music right now!
Cheers,
Mike.
Hmmm.... I may have spoken too soon, it's greatly reduced but still there.
At least it no longer flaps cones without even having the TT switched on, but there is still the occasional dodgy looking cone excursion when playing some records.
Possibly reacting to warps?... maybe I need some LF filtering as per the 3S?... Peering at the schematics, it shouldn't be too difficult to incorporate.
First I'd better get it 'up on blocks' and dust off the scope, make sure there's no funny business going on. http://www.wduk.worldomain.net/forum/images/smilies/confused.gif
OK, some progress has been made here.
I've had a couple of PM's from Nick and asked a few question on the WD forum. Nick's suggestion of getting the scope out was the key, The B+ is bouncing around like a merry little thing and causing much weirdness.
Richard over on the WD forum mentioned replacing the C4S section in the PSU with a 15K resistor to see what happened. I did this and WOW!... What a difference. Cone flap issues completely gone and a huge improvement in bass performance.
I'm pretty sure I've got this active section wrong somewhere which in conjunction with a decoupling cap which shouldn't be there has been causing all sorts of instability problems. I'll have a good close look a little later once I've smoked a few fags, drank a gallon or two of tea and got rid of my headache! All this peering at little things and reading stuff has given me a 'blinder'! :doh:
Laterz,
Mike.
*Note to self* - Go to the sodding opticians you pillock!!!
What current did you set the C4S for?. You need to see if its passing enough current.
The values on the PDF worked for me with the LED's I used, but it may be that even if its working as a constant current source, its not passing enough current to supply the phono stage AND keep the VR tubes lit in your case.
Errrr...... :scratch:
Dunno TBH, I just built it!..... Erm, with these LED's: http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=2285922&x=10&y=13
How do I check it?
couple of 9v batteries and a 100 ohm resistor, Connect batteries in series, then connect the CCS and resistor, apply 18v across them both, and measure the voltage (and hence current) across the resistor. You need to aim for about 10ma + whatever the phono stage draws, so about 15-20ma would be ok.
Its also worth pointing out that the phono stage that the power supply powered was different from the WD one as well, the first stage has a much higher PSRR than the standard one, also there are no decoupling caps on the B+. With the regulator, as long as the connecting wires are not too long you don't need them, maybe a 47nf cap where the B+ comes into the second box, with maybe a 470pf ceramic to take care of any RF picked up.
http://www.lurcher.org/nick/audio/Phono-2.gif
(PSRR = Power supply rejection ratio)
so about 15-20ma would be ok.
105mA is probably wrong then! :scratch:
Arrrggghh!!!!....... I've killed it! :(
I've popped the C4S section and in angry haste managed to snap the legs off the regulator in the heater supply.http://www.wduk.worldomain.net/forum/images/smilies/rolleyes.gif
It's dead but resurrect-able. http://www.wduk.worldomain.net/forum/images/smilies/redface.gif
Its one of the problems with silicon, it lets the magic smoke out far too quickly :-(
If you build another C4S, to test with a battery, it might be worth reducing the size of the lower resistor to ensure the LEDs are passing enough current. It wouldn't produce the 105ma result though.
I'm not even going near it tonight, I've broke it, missed the MotoGP, and got cross! :laser:
I'm going to drink some beer, have a fag, and come back to it in the morning when I'm nice and happy. :)
LOL. What are you like! :lol:
Thank f*ck I let someone else do all this pish for me so I can just concentrate on listening to music ;)
Marco.
Bah!.... to55er! :ner: :lolsign:
It'll all come good in the end, mate :)
You know what they say - no pain no gain...
Marco.
T'will all be right, in my own sweet time!
Patience young sly wanker. (Hmmm... Is that how it's pronounced?) all will be well. :eyebrows:
Until you fecked it tonight (!) have you made some progress since we last spoke in terms of the sonic issues you described?
Marco.
Good news, dude. Hopefully you're starting to hear how good that AT cartridge is.
Marco.
I've ordered some replacement parts (and plenty of spares!) which should arrive tomorrow. I'm going to rebuild the power supply on tag boards because I don't like how I've laid it out ATM, I find tags easier to work on too.
I'm determined to get the C4S section working properly so need to do some reading/learning coz my understanding of them is obviously poor. I can't seem to find much info about them on the interweb though, anyone got any pointers? :scratch:
Cheers....
I can't find any of the Camille original articles. Its a simple enough circuit, what do you need to know?
The small transistor acts to keep the voltage across the load resistor the same as the reference forward voltage across the LED (plus 0.6v for the Vbe of the transistor). The large transistor acts to prevent the small transistor seeing the high voltage.
I just meant CCS's in general...
I've found shed loads of stuff and it's making sense now. ;)
You can live without it for the timebeing. Its job is to provide improved isolation between the mains and solid state switching and the phono stage.
What voltage do you get before the C4S?
You need to replace the C4S with a resistor, and the value of that depends on the voltage from the supply.
Assume (for instance) you have 310v from the supply. You will have 250v after the resistor because of the VR tubes. You want about 10ma through the VR tubes, and another 5ma or so through the phono stage itself. So the voltage drop across the resistor is 310-250 or 60v, and the current is 15ma. So Ohms law gives us 60/0.015 or 4k. And the power dissapated in the resistor is 60*0.015 or 0.9w so I would use something like a 6w 3k9 wirewound
Hopefully you're starting to hear how good that AT cartridge is.
Bloody fussy about loading!.... Just changed from 100 to 50ohms and a different animal!
Most moving coils are, mate - that's the advantage of having variable loading, so have a play around.
The 103 only sounds right loaded at 180ohms; most people use it at 100ohms (because fixed MC phono stages set MCs at 100ohms or variable ones jump from 100 to 250ohms, and above) and it sounds pants like that.
Marco
I'll make sure I bring my soldering iron and suitable resistors to match your rubbish old 103 then! :lolsign:
Just got back from Andy's (SDDW) where me likkle old phono stage has had very stern test. Andy's system is rather 'high end' compared to my humble little setup and the Phono3 clone was called upon to fill the shoes of his rather splendid Modwright!!! :sofa:
I'm not going to tell you how it sounded, ahem!
Go on spill the beans - just how pish was it in comparison? :lol:
We won't laugh too much, I promise ;)
Marco.
You'll find out on Friday. ;)
Err... as long as I don't blow it up again! :D
Haha... Where's the fun in D.I.Y if you can't blow a few things up now and then? :eyebrows:
Electric shocks can be a wheeze, too.
Marco.
Electric shocks can be a wheeze, too.
Got one of those yesterday.
And two soldering iron burns!
:eyebrows:
Aye, yer a true martyr to the cause!
Great party game that - let's compare solder burns :eyebrows:
Marco.
'Catch the capacitor' was a popular 'game' when I was an apprentice.
A fully charged one of course! ;)
We used to get told off for that.
Marco,
What's your usual mains voltage?
Last night my phono stage threw a tantrum when fed 230V from Andy's mains regenerator thingy, but was fine with raw 240 mains.
245V or so, mate. It never goes lower than 243V... :)
Marco.
Mk2 PSU underway...
A nut, a nut... My kingdom for a nut!
Preferably one that fits this ere screw... Why is it always stupid wee things that cause all the holdups, eh?
:lolsign:
There's a big enough nut making it! :lol:
Marco.
Yeah, but I need a little nut....
You're no use though, I don't need another sea nut! (work that one out! ;))
I'm now completely f**king demented! :steam:
Earlier today, while I was looking for that bloody nut (for 2 hours or so!) I came across a 0.47R 9W resistor and thought "I'll need that later", and put it in 'a safe place'....
And yes, I've just spent another 2 hours or so trying to find it.... :doh:
It's just dementia, mate, don't worry about it.
Marco.
Mk2 PSU done. :)
http://img387.imageshack.us/img387/3760/p8211967zb8.jpg
By shian7 (http://profile.imageshack.us/user/shian7), shot with u30D,S410D,u410D (http://profile.imageshack.us/camerabuy.php?model=u30D%2CS410D%2Cu410D&make=OLYMPUS+CORPORATION) at 2008-08-21
AND!...... It works!
Which is nice. :)
Note comedy resistor cluster in the red box, this is where the C4S bit will go. PSU is completely passive at the moment but retains the gas VR tubes.
http://img176.imageshack.us/img176/6174/p8211967bt6.th.jpg (http://img176.imageshack.us/my.php?image=p8211967bt6.jpg)
The 103 only sounds right loaded at 180ohms
Hmmm... are you sure?
I've set it up as 180 to match your setting for the 103 and it sounds poo!
I hope it's just a cartridge thing. Where are your loading resistors fitted in relation to the set-up tranny, and what's it's ratio?
Mikey, just because the 103 sounds good loaded at 180ohms doesn't mean the AT will ;)
Loading on both the HA-500 head amp and A23 step-up tranny are set by the manufacturer. There is no variable loading because they're only designed to match one cartridge - the DL103.
Marco.
Thought so.... 180 Ohms it is!
I'll bring some bit n' bobs anyway, so we can play about if need be.
Sounds good, matey. Give me a bell when you're on the road to let me know roughly what time you'll arrive. You're welcome to get here as early as you like :)
I've got the Mullards ready for you, btw. Oh and don't forget to bring some familiar music on both vinyl and CD.
Marco.
I've got the Mullards ready for you, btw.
Great... That should be interesting. I'm rather taken by these 5751's though, but you never know! ;)
I'll be setting off as soon as Cath gets back from shopping and I've loaded up.
Nice one. On the subject of step-ups, I'd like your opinion on what you think is best with the 103 between the A23 and HA-500. I can't decide!
Marco.
Oh I can answer that from here!
You see, they're both for the 103. So both are shite! :D ;)
Hehehe....
Arf!
I think I'll be adding a 'wee something' to your seafood salad :eyebrows:
Marco.
Oh no... not another prawn and 103 salad! :rolleyes:
No, it'll be more like a prawn and laxative salad! :upyours:
Marco.
Oh thats OK then. Hold the prawns! :bog:
How about a roll with 'Sam & Ella'? :eyebrows:
Marco.
Hmmm.... maybe I'll have a roll with Ella. :eyebrows:
But Sam is all yours! :lolsign:
Have you tried those valves yet, matey? :)
Marco.
Nope... Everything is still scattered about the floor where I dumped it all on Saturday night. No 'play-time' till Thursday. :(
Been doing a bit of tube rolling between the JAN GE 5751's and some Mullard ECC83's that Marco has loaned me.
I came categorically say, err, not much TBH!... Apart from the ECC83's having a bit more gain I'm hard pushed to tell them apart, the extra gain is nice to have I suppose. More listening I think.
<wanders off rubbing chin> :scratch:
No worries, Mikey. Have a play and see what you think. When we tried it in my system with your phono stage to my ears there was definitely more clarity and less 'grain' with the Mullards, but it's your ears that matter most! :)
Marco.
Primalsea
01-09-2008, 20:42
Having a hankering for another DIY project and spurred on by Mike's sterling efforts to further the cause I thought I could continue this thread with another project.
I'm going about it in what may seem arse about face but I have my reasons. I'm making the case first and putting in the controls for the functionality that I want first. See pic for where I am currently.
I've done this as it will stop me from drifting off course and ending up not bothering to all that I initially want. Also having everything in a nice chassis with sections on their own sub chassis makes it a lot easier to build and then modify neatly.
What I want:
Power Switch, Always a good start
High/Low Gain Switch (MM/MC)
5 selectable input impedances
5 selectable input capacitances
2 Stage valve topology with passive RIAA
A switchable pre stage for high gain
Wading Through Treacle:
What Pre gain stage, something very quiet like solid state or step up transformers.
What valves to use, I seen ECC88 circuits but also heard that they're not good for phono stages. Point to point as the enclosure is already set up for this.
Whether to use the spare outlet of my WD Pre PSU and regulate this further, to have a separate outboard PSU or a inboard one.
Hopefully at the end of it I can have something better than my Project Tube Box for a couple of hundred quid.
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