It's happened to me too. In combo amps the vibration of the speaker interacting with the tubes is a part of the overall sound but the downside is that it puts the tubes at some risk of shortened life and catastrophic failure. Fortunately these are a cheap fix and I always keep a couple of spares handy just in case.
12AX7 preamp tube failure last night
I was playing a gig last night with my Vox AD50VT amp which has one 12AX7 preamp tube. Suddenly I lost all sound. Is that a normal failure mode for a tube? Is that uncommon? I bought this amp new almost 7 years ago and love the sound of it. I have a recording of the song when it failed and it seems like you can hear the tone breaking up and getting scratchy right before all sound was lost. Any ideas appreciated.
Bill
Bill