Info on shunt caps for Adcom GFA-545?

[nadams]

Can I do the shunt cap mod on my GFA-545? If so, what type of caps do I need? I'm very familiar with capacitors on computer motherboards, as I've replaced scores of bad ones. Audio caps, on the other hand, baffle me. :confused:

See here for pics of a 555 with shunt caps installed - http://www.polkaudio.com/forums/showthread.php?t=76378

Thanks in advance,

Noah

[ben62670]

You can easily do the mod. All you need is some 100v or better film caps like you would use in an XO. Now what values you use are controversial. I like either 12uf, or a combo of 20uf, and 1uf paralleled. I will be doing this mod soon. I had a 555 with the mod. I take a look at the schematic to see if there are any input caps that should be replaced. Shoot me a PM if I don't post an answer by this evening.
Ben

[nadams]

So then, I'm looking for something like this, right? - http://www.parts-express.com/pe/showdetl.cfm?Partnumber=027-430

Would I need 2 or 4?

[fredv]

4, one by pass per main filer cap.
I did this before I shipped my pair of GFA-555's the new happy owner.
This is a low cost way to give a little more helping zooom to the old caps. If you don't mind to spend a little more, replace the main filter caps with new low ESR caps will give you a better improvement. Of course, you can do both :-)

Have fun!!

[nadams]

If I could find replacement 10,000uf 100v caps in audio grade, I might entertain the thought of replacement. But I can't find a source for them!

[Face]

If I could find replacement 10,000uf 100v caps in audio grade, I might entertain the thought of replacement. But I can't find a source for them!

EPCOS

http://www.alliedelec.com/Search/SearchResults.aspx?Ntt=10000uf+100v&Ntk=Primary&sid=11F8E16DDA28&i=9&Pst=10000uf+&N=0&sw=y

[nadams]

Ooookay... I won't be spending more for the caps than I did for the amp just now. Maybe if it dies :o

[heiney9]

If I could find replacement 10,000uf 100v caps in audio grade, I might entertain the thought of replacement. But I can't find a source for them!

Nelson Pass swears by computer grade Panasonic filter caps, have you looked into those? Many DIYer's use his suggestion for their projects.

[fredv]

Nelson Pass swears by computer grade Panasonic filter caps, have you looked into those? Many DIYer's use his suggestion for their projects.
Ditto, I am quite happy with Panny. Digikey:
http://search.digikey.com/scripts/DkSearc/dksus.dll?Detail&name=P10038-ND

[nadams]

Ditto, I am quite happy with Panny. Digikey:
http://search.digikey.com/scripts/DkSearc/dksus.dll?Detail&name=P10038-ND

Except I need to have screw terminals - http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=338-1265-ND which of course quadrupels the price.

[fredv]

How about this?
http://www.diyaudio.com/forums/showthread.php?s=&threadid=135652
Pretty good price. Of course, this is still almost 3X of the Dayton .... But imagine you still can hear the music for 1 min after you turn off the power :-)

[rabies_70]

4, one by pass per main filer cap.
I did this before I shipped my pair of GFA-555's the new happy owner.


That's ME!!!! I have 5 555's in my HT rack now. The two from fredv have the mod. The other 3 soon will have it done. I just added the new cap to my CS350ls, now I'm opening up my Adcoms. Do it. The sound is noticeably improved. Thanks again Fred