Hi folks. Before I bring this amp in to a tech, maybe someone can give me some insight. Here is what happened: I was playing a show last night with the Bivalve into a 1x12 4ohm cab. Sounding good then no sound. One 6L6 tube blew and has a grey cloud at the top of the glass, and both preamp tubes blew. NO FUSES seem to have blown. I replaced 3 tubes and all lit up, yet NO SOUND. Maybe someone can advise.....thanks.