Vintage Modern 2266C weirdness

[Angus]

Because of the snow, I had to carry my 2266C down the track to our rehearsal place this week. We set up and jammed but all of a sudden I experienced a big loss of volume, and the guitar sound was nastily distorted. I assumed a valve had gone and used a spare amp and my Blues Driver for the rest of the time. When I got home I changed out all the valved in sequence, but nothing made a difference. I wobbled the speaker lead around.... nothing. I also noticed that reducing the amp's Treble setting to zero, increased the volume significantly. Then I randomly pushed the Bypass Loop button and suddenly all was well! Now I've never used those buttons as I tend not to use effects, maybe it was accidentally pressed when I carried the amp to and from the studio......

You're probably thinking "idiot!" and who am I to disagree? :-) But when the problem arose, the amp was working fine, nobody was within 10 feet of it, and the problem suddenly started. Which seemed a bit weird to me. :-/

Any thoughts - with which I can increase my wisdom? :-)

[surfnorthwest]

Plug your guitar into the FX return and see if you have the volume back. Doing this can narrow the issue to the preamp and not the power amp.

[Angus]

Plug your guitar into the FX return and see if you have the volume back. Doing this can narrow the issue to the preamp and not the power amp.

No Surf, let me clarify. :-) When I looked at the amp later, I pushed the Loop butoon (out) and everything worked again as normal. It's just that if that really was the problem, how could it have commenced when nobody was near the amp?

Just to be clear, the amp is absolutely fine now (fingers crossed!). :-)