I have owned this amp since January this year, I was playing away last night and things were pretty dirty, what with the tubes driving and the big muff going into the amp and buckers driving that! Anyway, there was a sudden loss of sound and the switch even stopped glowing blue. There was an acrid chemical smell and I assumed that the power tube had gone. I took the 20 (!) screws out to take the cover off and discoverd that it had come from the area of the 12ax7. I changed tubes out and changed the 250v fuse in the back, powered up - sound, lights, everything! I turned up to halfway and saw R12 fizz and burn up in front of my eyes! All still lit, no sound!! AT popped???