I've had no problems with my tube amps, even the ones I acquired used. The only exception is the 60 year old Super Reverb... was kind of like taking home the dog nobody wanted from the pound. But three prong cord, filter caps, and new tubes was all that was needed to restore a great sounding amp.
Last remaining problem was cosmetic; I play in "respectable places" and would need it to "look classy". The old Tolex was made by the General Tire company for Fender back then (modern is vinyl) and the decades resulted it it looking mangy (dry rot), coming off in places, missing in others.
I originally figured I'd re-cover it, but after removing the old stuff and prepping the wood (pine!) I decide to stain and finish it. I had never done any of that before, but worst case would be if it didn't come out well I'd go back to recovering it.
I used two different stains and minute applications of WD-40 and AmorAll while still wet, then finished it when dry with ChapStick and a few hours of rubbing.
Each of the four boards has a knot hole because all four were cut from the same piece - with a 3 foot diameter circular saw (the saw marks visibly emerged during the staining).

Recommandations for Hollowbodies for $600 and under?
Today, 05:20 AM in Guitar, Amps & Gizmos