Customer scored this amp on Craigslist for $60. The stock circuit was very similar to an early Bassman with octal preamps and a paraphase inverter. It probably would have sounded great as-is, but the amp was a mess with brittle and/or rotting wire insulation. I decided to just gut the amp and build something new, using spare parts where I could so it wouldn't break the bank - a junkyard build more or less.
The new circuit uses 6SL7GTs in the preamp/PI. The first two triodes are paralleled and the tone stock is driven by a cathode follower like a Vox top boost. I went with a cathode biased 6L6 output like the original amp - biased HOT with no negative feedback. The amp has full, rich sound - loads of harmonics - I really like this amp. I have a feeling it will just kill with KT66s.
