Adcom 565 amplifier HELP

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi Brad,
No. The breakdown voltage is important. The difference is too great here.

Hi montfriz,
How old did you say that amp is? Of course they don't have stock. The replacements would be as old as the amp as the parts are bought at the same time. However, you can find something the same approximate size physically and the same voltage and install those The actual capacitance is not that important given the tolerances. You may need to change to some PC mount parts but there is always a way.

-Chris
 
Montfritz,

I have new and unused Adcom power caps they use in the 300w/pch GFA-5802. The 565 is also 300w/pch so they should work. They are the same width but slightly short so they will drop just right in the current slots... that is if you can settle with the being 22000uf 100v .:smash: :smash: :smash:

That being said, I have 2-3 565's lying around and I can take out the big caps you want and put the 22000uF's for my use... how much would the 35000uF/100v be worth to you? I am just seeing if they are worth my time to sell them to you and go with the 22000uF (which by the way Adcom sells for $62.5 each ) ;)
 
The rails on the 565 are around 82-84vdc per rail depending on Mains AC.

Chris... Can I use a 100v cap (125v surge) on 100v rails? i.e. will the surge rating take care of the 20% margin that you need to have typically? Please note: It is Very hard to get caps over 100v ratings incrementally... you need to go to 160v or 200v both which are either too big or less capacitance. :dodgy:
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi Arif,
I am not comfortable with that. What if your average hydro voltage is boosted in a couple years? The life on the caps would be shortened for sure. How about some 65V units in series? I know, I would try to get around that as well but if it's the only way. Or find another brand using special order 125V caps and buy tho$e. 160V is not too bad except for the exponential pricing.

-Chris
 
Hello MJR :
Well buddy are you sure we have the same problem??? Mine ultimately lead in another direction. I got two caps from www.[url]http://jeacaps.com/[/url] (great service) now they are paperweights on my desk. See my amp was misdiagnosed and the caps are fine it was the caps and transisters on the driver board that were the problemmmm one had leaked and........the amp is fine now....I can say I learned alot from that little LEAK... Take a peek at this site http://www.angelfire.com/art2/stereorepair117/adcom.htm it pretty well sums up the problems ....hope this helps, any further assistance just send an e-mail.
Cheers Harold
 

mjraudio

Member
2007-01-26 9:43 am
USA
montfriz said:
Hello MJR;
35000 MFD
100 VCD
+/- 20 % 85 degrees C

Cheers Harold


Hmm, I have looked through various capacitor manufacturers such as Cornell Dubilier and have never once seen a capacitor matching the exact values of the original ADCOM GFA-565 capacitors (35,000uF @ 100V {125V Surge}). I just pulled the capacitors out of my amp...one works and one is dead. I really want to replace both of the capacitors with brand new electrolytics at the same time. And I want 4 of them so I can replace the caps in BOTH my amps.

Does anybody see any problems with downsizing the capacitors? Could I use 100V 22,000uF capacitors instead of the 35,000uF ones? Or would that create a mismatch between the capacitors and the massive torroidal transformer's power requirements and create problems in the amp's circuitry and function?

Thanks
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi mjraudio,
Does anybody see any problems with downsizing the capacitors? Could I use 100V 22,000uF capacitors instead of the 35,000uF ones? Or would that create a mismatch between the capacitors and the massive torroidal transformer's power requirements and create problems in the amp's circuitry and function?
No, but high power level performance into low impedance loads may suffer. Look at it another way. Works much better than an open cap!

-Chris
 

mjraudio

Member
2007-01-26 9:43 am
USA
@anatech: I respect your input at diyAudio forums as you are very knowledgeable and have helped many people with their amps. Thanks so much.

I'm going to order a pair of ADCOM 100V 22,000uF capacitors from JEA Capacitors on ebay, does this look alright to replace the GFA-565 100V 35,000uF capacitors? (I'm going to try repairing this broken one first before purchasing caps for the other, functioning amp).

http://cgi.ebay.com/2pcs-ADCOM-100v-22000uf-computer-grade-capacitors-NEW_W0QQitemZ200074177411QQihZ010QQcategoryZ36336QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 

mjraudio

Member
2007-01-26 9:43 am
USA