Sleeper Vintage Tube Gear?

Hello All,

I'm pretty good with a soldering iron, used to be a tech, and have built a few guitar amps from scratch as well as repaired/modded others soooooo…….

Any recommendations of vintage sleeper tube amps or preamps (home audio) that I can look for to repair, upgrade, modify that would be relatively inexpensive, say $200 each ?

Thanks