65' Super reverb Tube Trouble

[albania]

2 months ago i had back my old 65'super rvb, it was retubed with 2 sovtek 6L6WXT, but one of them overheated and ceased to function, im new at tube amps, but seems odd to me that a tube dies on just 2 months. my question is, what kind of problem could make a tube overheat?? by the way, i found some 6L6GC tube (dont know the brand) and replaced it just for 1 gig, worked ok.

[Alex R]

Could be biased wrong, or a problem in the bias supply, or just a bad tube (it happens, quite often).

[52 Bill]

Related to the bias problem that Alex mentions is that there may also be a problem with the tube sockets. If the connection to the grid opens up, the loss of bias to the tube can cause it to overheat.