Bias/Tube Rating for Kustom Coupe '36

[WilliamAmusic]

So, I just bought a set of power tubes about a month ago and at a gig this weekend, I noticed the "mini-fire" action goin on and pretty much no sound coming out of my amp. This troubles me, b/c it's the first time I've had to replace the tubes in well over a year and a half. This tells me that I've either gotten the wrong tube rating...which was '7' I believe...or the amp needs to be biased again and with that re-tubed also. I've read that these are self-biasing, but if this is the case, why are my tubes jacked in a month?! Advice?

[steelguy1]

Could it be you have been using the amp without speaker ? If so, this is probably the cause of blowing output tubes. Sometimes the output transformer gets fried when operated with no load on it.

[Blue Strat]

Incorrect bias wouldn't cause low output or no sound. Either the tubes have worse problems or something else is wrong. Pop the old tubes back in and see what happens.