Blackstar Artisan 100 with 2 burnt tubes and a blown HT fuse

[JustMike]

I can't find a schematic anywhere, but it's pretty much a 100w Marshall with a 5 position Voice control. 2 tubes on one side have burnt paint on them and the HT fuse was blown. I pulled the EL34's and checked the neg bias voltage, which is there.. so I put the tubes back in and the burnt tube side bias was way high and i could hear a random popping noise in the speaker. So I swapped the tubes to the opposite sides to eliminate the bias circuitry and the high bias voltage followed the tubes. So I then pulled the bad tubes and tested with the 2 good tubes (in both pairs of sockets) and the amp sounds fine. The sockets are white ceramic and I don't see any carbon or burn marks on them.
 My question is this; If one tube on a side shorts(?) or goes bad, can or will it take out the parallel tube with it?


Thanks,

[shooter]

tubes tend to die "normally" based on hours/operating conditions used, so if they all went in together, they all have the same "hours"
that said, the "high current" tube will suck up it's parallel brothers power, since the bad tube offers less "resistance" to ground

[Latole]

Power tubes must be matched pair with 9 ma or less.

One of you tube may be out of specs from the other one.
Bias could be too hot for one tube, it blow as you see.

You have to read power dissipation on each tube, not only bias negative voltage on grid.
I bias not more than 60 %. Often at 50% when I test sound with guitar