I have a '49 Gibson BR-9 amp. It has a strong smell when fired up if I haven't used it for a while. I plugged in the SG for a bit last night and it went into overdrive right away with the hot humbuckers. Roll off on the guitar an solo the neck pickup and it got a really creamy sound I wasn't expecting from the neck. The bridge pickup has a bad pot, so I don't know what it will do yet.
There is joy in undersized tube guitar amps.
They're my favorites to work on as well as lots of fun to play - especially the Gibsons.
