Every once in a while when playing through my amp, the sound through my cabinets "fizzles" (aka volume drops a LOT and it crackles and pops). It comes back up after a while, but obviously something is up. I've tried new instrument cables, my preamp in my bass has fresh batteries... I do probably need to replace the speaker cables, but usually when those are shorting out you can trouble-shoot it by jiggling them, no such result doing that. I've noticed it does it in my bedroom when I'm practicing and the A/C unit outside my bedroom clicks on. Or when setting up for a gig and sound checking with a fan plugged into the same power-strip. And yesterday we were practicing in the guitarist's garage and it was acting up every so often (lord knows what was running in the house). Also note that in my bedroom and yesterday at practice I was not going through a power-strip. Is this a case where a power-conditioner or surge protector is needed? Or maybe a new power-cable for the amp-head itself?