Adcom GFA-555 ii power amp filter caps

[Electone]

I picked up a mint 555ii last week and I'm just going over it. I did some measurements on the four big filter caps and it seems one of them may be dying. They are the original Adcom 15,000uF 100V caps.

1. 15.96mF, ESR 1.2ohm, Vloss 0.9%
2. 10.16mF, ESR 1.2ohm, Vloss 1.6%
3. 15.92mF, ESR 1.3ohm, Vloss 1.9%
4. 15.36mF, ESR 1.2ohm, Vloss 2.3%

Questions are would it be ok to leave things as they are, or should I replace cap #2 or replace all four.

The amps sounds perfectly fine as is and is very powerful.

Thank-you in advance.

[redwire]

Re: Adcom GFA-555 ii power amp filter caps

Nice!
I would run the amp for a while, the caps might just need reforming, if it was out of service for a time. Then recheck the capacitance... But not in-circuit.
They are expensive caps to change out.

[Electone]

Re: Adcom GFA-555 ii power amp filter caps

Sounds like a plan. Exact replacements would be cost prohibitive. I was looking at some CDE 382LXs but they are not screw terminals, so i'd have to modify the connections.

[budm]

Re: Adcom GFA-555 ii power amp filter caps

You may not even notice anything unless you run the amp at full output power spec..

[redwire]

Re: Adcom GFA-555 ii power amp filter caps

The CDE screw type cans are over $100 each, ouch. But only 75V or 100V. Snap-ins are $17 each. Not sure why.