Two things to mention, first, I guess you read that Wilson Pickett had died. I am sure his Obit. is available on the web.

The main reason I am writing is that something weird soundwise is going on with my Peavey amp. It is producing a tone like a ring modulator distortion. Here is what I have done to try to isolate the problem. First, you should know that it is a trans tube amp, meaning it has a solid-state pre-amp (trans) and a 4-tube power amp. As you know, for I think it is the B class of tubes, they work in pairs, outside and inside pairs. I took one set out and then the other, same bad tone either way, so it does not seem to be in the tubes in the power amp, though it could be two bad tubes at the same time, one on the inside and one on the outside. Another thing I tried, thinking the distortion was from a bad speaker, say a bad voice coil problem, was to use my 2-10 speakers instead of the amps 2-12s. Same bad tone. To see if the problem is from the pre-amp instead of the power amp, I took the pre-amp out from the Peavey and put it into the power amp in on my Carvin. Beautiful tone.

My understanding is there is not much to a power amp besides the tubes, just a rectifier of some type (trans or tube) and transformer(s) – this thing has two big power transformers.

My Carvin is working fine, but I would like to get this thing back to working right. I do have all the specs and circuit schematic. Do you think it is the rectifier?

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I explained to my brother, one transformer is power, the other is output.

Any suggestions on the "ring modulator" tone?

I would lean towards testing, in case there is something in-circuit which is dangerous to good tubes. Not just testing in a tester, perhaps another amp as well.

Since you have the schematic, does it have any voltages on it? Can you determine if it is misbehaving in an outwardlymeasureable fashion?
cheers,
Douglas

We have the schematic, and I will be taking a look at the amp and Thermionic's suggestions this week.

My brother followed up, he did some basic trouble shooting. The amp in question is a Peavey Heritage. It has a solid state preamp section and tube power section. He ran a line from the pre-out to the pre in on another amp (a Carvin). And the preamp section is A-OK. He also ran the other amp into the speakers on his Heritage, and the speakers are OK. So, that did narrow the problem to the power amp.

He said the amp makes a "ring modulator" type noise. Thermionic had some good suggestion on capacitors in the circuit that could cause that problem if shorted out.

So, check in the guitar amp section as we troubleshoot this and solve the problem.

Thanks.