I've had my Smash for a while now - today noticed a faint crackling noise coming out of both channels during quiet passages - independent of the input source. It might be my imagination, but microphonics seem to be a bit more than in the past. My normal inclination would be to suspect the tubes & change them - but I can't seem to find a source for 4P1Ls.
Any suggestions on what to look at (or where to find tubes)?? I won't be able to do much for the next few weeks due to travel, but would like to get an idea what to attack when I get back.
TIA
Rich