I have a yorkville xm200t and about a week ago it was buzzing. i tried plugging it in to different outlets around the house with just my bass (no pedals) and it was still buzzing. after just sitting down and playing my guitar through it pretty hard for about ten minutes and when i stopped playing, the buzzing stop. so here it is a week later and i'm practicing with my band. at first it sounds great, but then it starts buzzing again(and i know it's not the chords/pedals/outlet) i know buzzing might be anything, but if any of you could shed some light on this issue, maybe give me some extra trouble shooting ideas it would be appreciated. Thanks! p.s. is it possible it could be the weather?