I was playing every Friday and Saturday during a 2 month period in a bar band (classic rock). I was using an Epiphone Alleykat thru the Vox. For a couple nights running I was noticing that my guitar sounded "fluttery", like there was a slight tremelo going on, especially on high notes, although I had no tremolo on. I disconnected my pedals so I could rule those out, and made sure I had no effects actuated on the amp, but the fluttering remained. So later I mentioned this to people, and the consesus was that maybe the one 12AX7 in the amp was going. So at home, I switched out the tube and it seemed to sound better.
So I'm back at the gig the next night thinking problem solved, but as soon as I played a note, there was the flutter. So now I'm thinking "oh great, the digital amp is living up to it's reputation for crapping out!". Nothing I can do so I bear with it. Then, I don't remember if it was later that night, or the next night, but I'm playing and I bend down to put my ear into the speaker, and then the fluttering was gone! I go "huh?" and then look up - and there was the answer right above me. I had been setting up right under an overhead fan, and that was causing the sound from my amp to swirl around with it, causing the fluttering I was hearing. So stood up and bent down several times to verify my conclusion. I was happy to have found the answer to the puzzle, even though I felt like a complete dunce for not realizing this sooner!
Byron
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) I heard that it can be awfully hot during Summer in Japan -poor guys.