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Table Dancing Double Multiplier Warmonger
This is an approximation for the preamp of an amp I love. It has multiple channels, wazoos, doo-dads, and what-nots. This is a bit different from the original. It’s only one channel. I moved a couple grid stop resistors to attenuate with the grid leak resistors. Their values are different than the original, but are scaled to do the same functions. I changed the value of parts of it to reduce noise, but have approximately the same frequency and performance responses in most cases. I changed some of the cathode resistors to a more common value, but it’s close to tolerances and barely shifts it into a colder bias that makes little difference. Some of these changes are also because it doesn’t need to have all the extra stuff in the overall circuit if it’s only one channel.
This is NOT an exact clone. I think of it as a distillation of godliness into a smaller package with some wiggle room for my own preferences. I didn’t include the tone stack, PI, or output. I’ll leave that up to anyone who would like to further tweak it, in case they want to have a feature or omit a feature. It’s about flexibility.
Some notes about the schematic:
- My software barely supports tubes and the pins are all labeled for 6,7, and 8. This obviously is wrong on some of the tubes, but I couldn’t change it. V2 and V4 would be 1,2 and 3.
- It doesn’t have a model for a regular mono jack or a cliff jack. The stereo jack works fine enough for demonstration and I’m sure a person would be able to figure out what to do.
- You can change the input grid stop resistor to taste. The original uses an alternate way of attenuating radio frequencies and I chose a small value to prevent attenuating the guitar if it’s volume knob is turned down a bit.
- You might consider lowering the value of V4’s cathode bypass cap if the bass response is too mushy. Removing it altogether along with it’s series resistor might not be a bad idea, but will also attenuate the highs by a great amount and greatly reduce the gain of that stage.
- A somewhat smaller value on V3’s anode bypass cap will brighten the sound a little. That’s there mainly to prevent oscillation, but it’s cutting a huge chunk of frequencies right out of the stage that aren’t going to oscillate.
- I made the grid stop resistor for V4 56k. This is pretty low, but is partially to offer less attenuation and lends some brightness after some of the larger values upstream and to offset some of the attenuation in v3’s circuit.
I welcome any comments, questions, suggestions, or cease and desist letters anyone has.