• 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.

SE amp problem


2007-12-19 11:56 am
I just finished my first project. An all tube SE kt88 guitar amp with reverb. When I turned it on everything sounds fine, but when I turn the master volume above one quarter it starts to produce some audiable high frequency oscillation through the speaker,and a moment after that something starts to hiss in the amp head (I think it is the OT). I also noticed that if I turn the reverb full on, and the master volume just below the oscillation, then if I turn the reverb lower it starts to oscillate again.

Any ideas?