So the other night my idiot drummer (who we recently fired) moved my head while we were loading for a show and put it in a slightly precarious location. It ends up falling and you hear some stuff sounding like it's breaking inside. The center two tubes fell out. I take the thing apart, make sure everythings tight, warm it up. One of the tubes that fell out lost it's ability to fire up, so I remove the pair, it works fine with 4 tubes. I remember a while back someone on TB said they used their Bass 400 for a leg of a tour with only 4 power tubes. Well, it worked fine at the show. I cranked it a little extra and apparently drowned out the whole band with my 4x10. hah! I'll still have to take it to a tech and KT-88's aint cheap.