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What do you think of this overdrive schematic?


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This should look extremely familiar. I'm thinking of using something like this for a powered overdrive effect. I'll add a true bypass switch later... a pair of DPDTs that I'll melt a plastic bar across O:)

 

n1033398210_48126_3976.jpg

 

Any thoughts? (will this even work?)

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This thing's totally untested (hence "something like this") and the resistor values need modification overall.

 

That being said, someone added a second 12AX7 tube to the VJ, in which they used a 1M fixed resistor out of the first stage as a signal attenuator to reduce the power level to something acceptable to feed to the second 12AX7. I'm assuming the pre-amp still wants to bring source signal up to line-level, and would prefer I not feed it line level signal; thus, the jack going OUT to other effects pedals/my amp has a resistor there that'll force half the signal to ground AT LEAST (as Volume approaches zero, the vol pot to output approaches 1M and of course the shunt to ground approaches 100%)

 

This schematic is basically the 12AX7 preamp stage of the VJ, with volume marketed as "Gain" because it's meant to overdrive the tubes and then emit a source signal that sounds overdriven.

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I think you should try it. Maybe into something with a DBV meter so you can see where its at as far as signal strength.

But it does look like it might do what you want....and yes I noticed the similarities to the VJ preamp, which is why it should work.

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http://www.kbapps.com/audio/tubespecs/12ax7p02.html also here's a reference 12AX7 circuit if anyone wants to take a ground-up run.

 

Yeah, I could actually measure the input signal on a multimeter, and measure the voltage across various parts of the circuit and adjust resistors as needed to make it work. Wouldn't be hard. Probably be the most dynamic overdrive effect ever (i.e. a real tube) but it'd take a real power source (wall power)

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Well I can't remember where I saw them, but they make small switching power supplies that plug into the wall just for tube overdrive pedals. I'll have to search around and find out where I saw them. I think they put out something like 200+ volts so preamp tubes can run where they should.

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Oh okay, I'm dumb.

 

The electronics have some resistance, and so much voltage passes through. Given that, they'll draw so much current. Regardless of having 6000 amps available, they'll draw whatever they damn well please; so a 6.3V@3A going at a 1.5A 6.3V filament is going to feed it 1.5A.

 

I think.

 

My bad for not knowing **** about electronics.

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