Tonight at rehearsal all of a sudden my channel 3 and 4 volume levels went WAY low. I had to turn them on like 8 and 9 while channel 1 and 2 were on 3 or 4. I have been playing fine until then with my levels are set within reasonable ranges of each other. All 4 channels are running the same tube configurations so I know it wasn't that. All channels just use speaker A - and I checked that so I know it wasn't that. Channel 3 uses vintage rect while channel 4 uses the diode... so I know it wasn't that. I had my power switch set to spongy but I thought that affected all 4 channels? I switched it to bold and the problem seemed to go away but now I am paranoid of it happening again and we have a gig this weekend.
Do I have tubes going bad or what???
Do I have tubes going bad or what???