Take the caps off of your pre amp tubes. Turn the amp on without a guitar plugged into it and tap the pre amp tubes with something to the nature of a pencil. I use a drumstick. If you hear a ding noise coming out of the speakers it means your have a bad pre amp. Based off of the description is...
Yeah I know it's not the power. I tried different guitar cables, guitars, speaker cables, power chords and outlets. I tried it at our practice space and at home. Just bought a new set of tubes. they were all 5 years old anyway.
Of course when we go to start our show last week I start getting a buzz and a small sputter here and there in channel three. I'm assuming it's the v3 pre-amp tube. Suggestions?