Over 30+ years, I haven't found any amps that sound nicer or are as simple and basic (as far as controls, features, etc.) as an SB-12 (see image) Volume, bass and treble; 2 inputs, power switch. That's it. In a perfect world, a normal speaker output, and a standby switch would be nice. I'm looking for a very basic tube bass amp for rehearsal and small bar gigs. A well used (and cheap) SB-12 would be cool, but they don't turn up at garage sales like they used to; I'd say that there are very few remaining to be found. What other amp heads have been made over the past several decades that are as straightforward and simple as the SB-12? (simple from a user's perspective - I'm not qualified to say whether the amp circuitry is also 'basic'.) Even the earliest fender bassman heads had two channels, which I consider needless extra stuff. are there any similarly basic 40 to 100watt tube amp heads on the used market? Prefer single channel, minimal EQ (no more than bass, mid & treble) no fx send/returns, graphic EQs, weird boost circuits, etc. something that would be inexpensive to obtain, simple to maintain, and not too expensive to have serviced. An amp that could drive a 1-15 cab (at 8 ohms) and, in the future, two 1-15s (at 4 ohms) simple, rugged and capable of great sound (when returned to top shape) - suggestions???