Since I was in another room when the fuse blew, I didn't see if there was any arcing in the tubes. But they look OK, getters are still silver.
Opened the amp up just now to take a look inside. Everything looks OK, save for the quad cap resistor. A bit of the ceramic housing is gone from one of the legs. Possibly blown?
What do you all think, does that look blown? Is there a way for me to test it in situ?
If so, what does that indicate? Especially when considering the blown fuse and all. Bad Quad Cap?
If it helps narrow things down any, I was running Sovtek 6550 tubes, and a vintage Mullard GZ37 rectifier tube. I've got the auto bias board installed. I learned just yesterday that my mains voltage is a bit high at 123v, so I bought a variac to set it down to 117 per Bob's advice in another thread.
I'm looking forward to getting this amp up and running again, so I eagerly await and much appreciate any advice and insight from the community here.