• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Adcom GFA-565 Issue

G

Gliocas

New Member
I have 2 Adcom GFA-565 Monoblock Poweramps and while both turn on having power, they are not delivering any sound to connected speakers. The speakers work properly as well as the cables connecting them function. Also, there's no "pop" noise when turning the amps on from the speakers connected. There used to be this noise when switching on the amps, along with the sound being delivered to the speakers, but all of a sudden this has stopped. Any advice would be greatly appreciated.
 
Register to hide this ad
Odd that they both are seemingly inoperative at the same time.

Got a spare amp to check the upstream components?
 
Indeed, my thoughts exactly. I have a Benchmark DAC going to an Adcom GFP-565 preamp, then into the monoblocks. I've tested each component down to the GFA-565s and all work as expected. For instance, I connect my JL Audio (powered) subs to the preamp and they function just fine.
 
Hmmm. As I recall, the 565 pre has a couple of outputs? (My 565 has been slumbering for years). Tested all outputs? Eliminated the DAC for the simplest audio chain? Odd.
 
Have tested all outputs on the 565 pre. Haven't yet eliminated the DAC, but have however connected the DAC directly to the 565 monos with the same outcome (no speaker "pop" as it used to be of course, and no sound - which thus I surmise is interrelated).
 
Are there fuses on the outputs?
If there were and they were blown, you might see these symptoms.
 
I just went forward with replacing all 4 fuses and everything works again! Thank you all for your advice and assistance in resolving this matter, greatly appreciate it!
 
Glad it is all working again.
But I hope the blown fuses are not a symptom of a problem rather than an accident.

I've got two GFA555 II's and have been nothing but happy with them. At some point in the future, I want to do a preventative-maintenance/upgrade and at the very least will do a re-cap. The new input boards on Hoppesbrain are very interesting but a bit pricey for me.
 
Gliocas said:
I just went forward with replacing all 4 fuses and everything works again!
Click to expand...

I'm not AK's leading proponent of prophylactic re-capping, but I would suggest doing it for the driver boards on this amp, to prevent the electrolyte leakage problem mentioned above.
 
chazix said:
I'm not AK's leading proponent of prophylactic re-capping, but I would suggest doing it for the driver boards on this amp, to prevent the electrolyte leakage problem mentioned above.
Click to expand...

It does look like there is almost a 100% chance of failure of certain electrolytic caps with amps from a particular time-period.
 
Gliocas said:
I just went forward with replacing all 4 fuses and everything works again! Thank you all for your advice and assistance in resolving this matter, greatly appreciate it!
Click to expand...
The boards will fail. Fix then now or fix a blown amp later.
 
You must log in or register to reply here.
Back
Top Bottom