I bough a new/used tube amp that uses EL84 tubes. It sounded good. Within a day I was eager to do some tube rolling. I ordered some tubes to try.
Then I remembered I had a sophia baby tube amp with the same tubes....oops, they weren't the same. They were actually 6P1T...different pin out that provided a dead short.
I figured it out when no music came out and I smelled the hot smell. Turned it off but too late.
Openedit up and found the blown resistor. Only cost $5 and had it back in service the next day but it was a bonehead move.
Jerry