So I noticed that one of the power tubes (second from the left) was not lighting up. I figured that it was a dead tube, so I replaced the pair (the two middle ones) with a new pair, and left the other two in.

Right when I turned the amp on, I noticed that only the third tube from the left was lighting up, and none of the other tubes seem to light up at all.

I had a gig so I just switched the tubes back. What should I do?
Does it sound bad, if it still sounds good then I wouldn't worry about it.
"A well-wound coil is a well-wound coil regardless if it's wound with professional equipment, or if somebody's great-grandmother winds it to an old French recipe with Napoleon's modified coffee grinder and chops off the wire after a mile with an antique guillotine!"
- Bill Lawrence

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