Last night I played a gig at a club in which I've never had any amplifier noise problems. Previously at this club, I had always used my EA iamp800, but last night I thought I'd try my beloved Clarus on the gig, since I felt that the 800 was a bit of overkill (it sounds great, but is a huge schelp). Anyway, the Clarus ended up sounding great but was subject to an annoying buzzing or humming that wouldn't go away, even when the master volume was turned all the way down. The sound man said that the sound was "AC hum", and the drummer said it was a "60-cycle hum". If that is correct, what is the nature of the problem? Is it necessarily a function of the amp, or could it also be patch/speaker cables or preamp? If it's the amp, is there some sort of filter I could stick under the seat of my car for instances like this? It was very frustrating. Tonight I plan on bringing the iamp back in and seeing what happens, but I love my Clarus and would like to find out the nature of the problem, which I've never had before with this amp.