Sonic Cap help

[heiney9]

I am replacing some small value caps around the op-amps in my Adcom dac.

What's the difference between using the Sonicap Gen I or Gen II for this application. I need to get them ordered before the sale ends. The Gen II's physically are a tad smaller.

Any ideas which to get for this application? I need these values

(2) 0.022uF
(2) 0.0039uF
(2) 0.0027uF

H9

[heiney9]

Dammit...................NM, I should learn to read

The Gen I is basically a fairly balanced capacitor. However, some find our "balanced" slightly thin and bright compared to the more lush "colored" capacitors which would include the Gen II. While the Gen II has a nice Midrange bloom, Gen I has a slight advantage on the freq extremes (top and bottom).

Still you can add your impressions

H9

[backsigns]

The size of the gen 1's are only slightly larger than the stock caps in there. They fit in perfectly.

[F1nut]

Go with the Platinum's, if at all possible.

[backsigns]

Go with the Platinum's, if at all possible.

The problem is the correct sizes, they don't got.

[george daniel]

I ordered the Gen 1's,, I hope to have them tomorrow,, and for those of you who perform this mod,, there is a "bonus" tweak,, compliments of Fred that I have already disclosed to backsigns,, and H9 yours will be in your package.;)


If anyone here owns an Adcom DAC,, this is a mandatory mod. ;)

[F1nut]

The problem is the correct sizes, they don't got.

Have you asked Jeff or Elliot for custom values?

[backsigns]

No, but I never thought to.

[F1nut]

Ok, just ask and they will do their best to accommodate.

[heiney9]

3 issues with the Platinums Jesse,

1) hate to say it but cost. Not building a balls to the wall mod here.
2) physical size is a big concern as real estate is very limited.
3) values are way off

I need 2 of each

0.022uF is avail

0.0027uF and 0.0039uF aren't close to anything they have, not that they couldn't custom make them for me. Just guessing I'd have more than $120 just in Platinums.

I am going with the Gen II's just because of the description of having some midrange bloom. I really want Auricaps but they don't make the values I need.

H9

[F1nut]

Gotcha.

[Face]

You can use Relcaps for the tiny values.

[heiney9]

You can use Relcaps for the tiny values.

Do you think that would be a better choice sonically? Where should I ge them from?

[Face]

Sonic Craft sells them. I believe Jeff recommends them in some applications over Sonic Caps, I've give him a call or email him.

[heiney9]

Sonic Craft sells them. I believe Jeff recommends them in some applications over Sonic Caps, I've give him a call or email him.

Sounds good. I'm not even sure how much impact these have, but I'm guessing they must, or Adcom wouldn't have used higher quality mylar caps in those positions at the time.

H9

[F1nut]

You can use Relcaps for the tiny values.

Good suggestion.

[billbillw]

What type of caps were in there originally? What voltage rating do you need? Are they coupling caps or bypass caps? With small values like that, you might need to look at another type of cap all together. Maybe a polystyrene cap.

[heiney9]

Good suggestion.

Except now I can't make up my mind. Well sort of since Relcaps don't have a .022uF cap. They have the other values.

Decisions, decisions :p

[heiney9]

What type of caps were in there originally? What voltage rating do you need? Are they coupling caps or bypass caps?

I believe coupling and they are poly's rated at 100V I need these values

2700 pF or .0027uF
3900 pF or .0039uF
.022uF

and they need to be small to fit in a very tight spot.

H9

[billbillw]

Are they the yellow caps, C540/543, C541/544, and C560/561? As far as I can tell, those are all bypass caps. Are you just changing them for an upgrade or due to damage? I honestly don't think changing them will have much effect on the sound. Have you looked around over at DIYaudio to see if anyone else is doing mods on this DAC?

EDIT: I checked and nobody at DIYaudio seems to be talking about the GDA-600.

Honestly, after looking at the scat, I'd focus on the power supply and the actual opamps. That's where your biggest gains will be.

[heiney9]

Are they the yellow caps, C540/543, C541/544, and C560/561? As far as I can tell, those are all bypass caps. Are you just changing them for an upgrade or due to damage? I honestly don't think changing them will have much effect on the sound. Have you looked around over at DIYaudio to see if anyone else is doing mods on this DAC?

Yes those are the ones. I have been talking with George Daniel about his mods and am going forward with everything he has done so far. I thought since I was in there doing everything I might as well replace those too. They used polys in there for a reason. If you don't think it will matter then I can save about $40.

Here's thread. Some additional caps are added to the op-amps and then grounded so maybe replacing the yellow poly's isn;t going to have any impact.

http://www.polkaudio.com/forums/showthread.php?t=97185

H9

[billbillw]

I doubt you'll hear $40 worth of improvement, but I'm not a guru on this DAC. However, I'm pretty sure those are just used as filter/bypass caps to clean up the signal coming off the DAC (remove ultrasonic and subsonic info).
I'd ask someone who knows more about circuit design. Its not like you can't do it sometime later.

EDIT: Looking through George's thread, I'm really surprised there is no mention of the power supply caps. After nearly 20 years, I'd be replacing those suckers. 6x2200uf plus a handful of 10uf.
I've seen huge reductions in noise floor by replacing power supply caps. They are after all, the main components that go bad after time. Most (back then) were only rated for a few thousand hours.

[heiney9]

Thanks for the input. I believe the PS caps are replaced as well. I think perhaps George didn't mention it, but I think he has in subsequent e-mails to me.

I'm sure he'll chime in when he has a chance, to clarify.

H9

[heiney9]

Still on the fence about Sonicaps for this particular mod. I can get all the other parts I need from Parts Connexion, thus saving me multiple shipping and minimum order charge if I have to order from another place like Sonicraft.

The only other film caps I've found in the small values in need are Multi-caps (PPMFX). Many say the RTX line is the best but they don't make the values I need. I'm torn. What do people think of Sonicaps vs. Multi-cap PPMFX. I read one review where they felt the Sonicaps were clearly better.

Face, F1 anyone have an informed opinion.