2100-65 buzzes in standby

I have some bleed coming from somewhere. I replaced the filter caps and the caps on the rectifier board. This is a SS model. I still have a buzz under the tone on hi or lo and the buzz is there on standby.
Any suggestions?

Hi Cyle,
if we assume that your standby switch works correctly, there should be no B+ on the output tubes and hence no sound whatsoever coming out of the speaker in standby.
Do you still hear the buzz if you unplug the speaker from the amp? If you do, you need to start checking voltages in the amp to ensure that the power supply is operating correctly. You could have a faulty standby switch that could cause some peculiar symptoms.
Sincerely,
Lars Verholtwww.captain-foldback.com

It's not a constant buzz. It's a faint distorted undertone of whatever you happen to be playing in Hi or Lo & you still hear it on standby.

Do you hear it JUST after turning it to standby? What I mean is, does it continue to do it for a long time or just a few seconds? The caps COULD be charged up and just take time to disipate the voltage or does it do it after several minutes of playing on standby? Mike.

Sounds like you have crossover distortion going on. Time to check for leaking caps.
Sincerely,
Lars Verholt

It never goes away. Like I said, I've replaced the filter caps and the caps on the recto board. I'm gonna try replacing the electrolytics on the preamp board to see if it helps. If not, I'm wondering if it could be some sort of bias issue, I've never had it checked.

Hi Cyle,
yes - the bias may need adjustment. The only way to get to the bottom of it is to get a 'scope on it. Anyway, if one of the coupling caps before the driver transistors is leaking (as in DC leakage), adjusting the bias may not solve the issue. A few mV offset caused by a defective cap makes a relatively large difference in this particular amp design.
Cheers,
Lars Verholt

Hopefully, changing the blue electrolytic caps on the preamp board will do it. If not, it's for sale.

With all the work you've already put into it, THAT would be a shame.

It's leaking DC voltage to the Chassis, just can't figure out where it's coming from.

Still searching

How much dc voltage are we talking? A few mV or a crapload?

All 16v

Finally changed the caps on the preamp board, cleaned the bias pot and set the bias. All better.

Good-glad to hear it. Did it clean up all the bleed? Mike

Yep. Like new. Now I need a back panel