WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
I have a Mesa dc10 that in the last two days has started making a phase shifting noise. I have only noticed it in the overdrive channel. The noise comes and goes at random. Any ideas as to what is causing this?
i would guess RF interfiernce and/or oscilation in the amp. its possible that a filter cap has gone bad, but first thing to do is try a tube swap and re bias.