So some of you probably know some of my story already....replaced all my tubes in my SVT, brought it to a tech for piece of mind but everything was good. I played two gigs and practices and everything was great... I let my amp sit and cool for about 90 min after a gig loaded it in my van and left it overnight...it was a pretty cold night, maybe 30, but it was covered and the van is pretty well insulated. Brought it in the next day, took it to practice, warmed it up and BUZZZZZ.... That's it, lights are green, no changes/sound from playing bass, when I dial the bias lights to red the buzz increases but that's about it, as it would under normal circumstances when there is sound...no output other than that. Tried cables, bass and cabinet... Thanks for the help!