Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => PC Express and JSchem - Schematics and Layout diagrams => Topic started by: Fresh_Start on September 13, 2009, 09:07:50 am
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Someone on the Ampage forum asked about a non-Reverb Princeton with a switchable gain stage to simulate the AA1164 circuit. Here's what I came up with as a first cut.
Please let me know if the 470K resistor to ground on the grid of the V2a is necessary. It looks like the lower leg of a voltage divider with the 3.3meg in the AA1164 circuit.
This should be a nice, simple amp to build. A 6BM8 version would only need 4 tubes total and might be really cool.
I have NOT built this amp.
Chip
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My logic says.. YES.
You should try a boost function that lifts the tonestack ground. Add a switch and limit the lift with a resistor (around 50k works well). Or use a pot and a switch and provide a variable boost.
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My logic says.. YES.
You should try a boost function that lifts the tonestack ground. Add a switch and limit the lift with a resistor (around 50k works well). Or use a pot and a switch and provide a variable boost.
The 25K audio taper Mid pot was intended to go in that general direction. However, I really want to try your "Girth" control someday soon.
Frankly, I think this circuit would be too clean without the bypass cap engaged on the second triode.
Chip