Snfoilhat
Tele-Afflicted
Design goals: harmonic tremolo and spring reverb, a power amp that sounds good in the work room and hits peak goodness at a volume only a little above that, and mid-sized combo cab built from some reused material.
I found this mahogany that had once been a very simple bookcase, with just a few holes that make me think it was pegged together. 11.25" wide by a bunch of feet long.
I chose a repro Bassman chassis for the extra depth vs. something like the Deluxe Reverb, and then began working out how everything would fit.
I have a 12" speaker in mind but want to be able to use a 15".
I looked at the source material for proven circuit 'modules' for harmonic tremolo and reverb and the rest and counted up the tube complement and their voltage and current requirements, then picked transformers.
Then I set out adapting the Bassman chassis to work with the power transformer, tube sockets, controls, and other features of the new amp.
Here's an idea of what the circuit will look like. You can see it draws on the brown and black Fender amps, and the only really unknown parts are the voltage dividers that join each familiar module, because I'm aiming for a smaller signal at the last stage of this amp than the Fenders were. Also, driving the cathodyne phase inverter directly from the plate of the oscillator instead of the later brown Fender arrangement of oscillator > cathode-follower > cathodyne is something I've seen others discuss but haven't yet done. I took notes from the earliest brown Fenders and think I've hybridized the 4-triode and 5-triode versions -- we'll see!
First draft, untried
I'll post more progress (or the opposite) when I can. Thanks for reading.
I found this mahogany that had once been a very simple bookcase, with just a few holes that make me think it was pegged together. 11.25" wide by a bunch of feet long.
I chose a repro Bassman chassis for the extra depth vs. something like the Deluxe Reverb, and then began working out how everything would fit.
I have a 12" speaker in mind but want to be able to use a 15".
I looked at the source material for proven circuit 'modules' for harmonic tremolo and reverb and the rest and counted up the tube complement and their voltage and current requirements, then picked transformers.
Then I set out adapting the Bassman chassis to work with the power transformer, tube sockets, controls, and other features of the new amp.
Here's an idea of what the circuit will look like. You can see it draws on the brown and black Fender amps, and the only really unknown parts are the voltage dividers that join each familiar module, because I'm aiming for a smaller signal at the last stage of this amp than the Fenders were. Also, driving the cathodyne phase inverter directly from the plate of the oscillator instead of the later brown Fender arrangement of oscillator > cathode-follower > cathodyne is something I've seen others discuss but haven't yet done. I took notes from the earliest brown Fenders and think I've hybridized the 4-triode and 5-triode versions -- we'll see!
I'll post more progress (or the opposite) when I can. Thanks for reading.
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