Two gain pots on Tubescreamer with individual clipping?

[pott]

The big dotted line is where the clipping would normally occur.

I have a dual gain pot OD which shares clipping, but I'd like to mod it as above to get two different channels as opposed to two channels of different gain (pot 1 is of a different value from pot 2 but clipping is as normal in a TS style pedal)

Say for the sake of clarity that gain 1 (lower pot, rythm) = 1N4148 + LED/1N34
Gain 2 (higher pot on schems, higher gain) = Transistor (as clipping diode)/1N4001 + 1N4148

Is that easy and doable as in my diagram (paint skills right there eh?) or would that cause issue with the ground?

Say for the sake of clarity that gain 1 (lower pot, rythm) = 1N4148 + LED/1N34
Gain 2 (higher pot on schems, higher gain) = Transistor (as clipping diode)/1N4001 + 1N4148
My diagram uses symetrical clipping but just ignore that...
Thanks!

[pott]

If it DOES cause issues I can simply rewire the LED side of the switch to the other end of the pots and use only one side with a clipping LED so I'll still see it!

[oskar]

Hi!

I don't think I really understand what you're trying to do.
If you wan't two channels with different diod setup ( you don't need to duplicate the diod's for two channels, only the resistance ), this is more like you would do it. There will probably pop however...

1. When you throw the switch, for a fraction of a second, your amp is going to act like a comparator heading for one of the rails since it
no longer has a feedback. I cure this with R1 in my drawing. R1 = ~1M - 2M.

2. It will probably pop when you switch anyway.   


ps. I forgot the 51k resistor. It should also be duplicated to this "dual channel".

[pott]

Ah the pop is what worried me... I'd need a DPDT to switch out the other side too then right? That's also doable using this pedal I think...

[oskar]

No, You'ld either need a digital switch. Like two CMOS4066 gates. They switch fast enough for popping to be over audible frequency.
Or you would need to make the resistor variable like a vactrol ( light dependent resistor/ LED ), but that is for a setup with only variable gain, not switching in or out clipping diods. I'ld go 4066. I kind of like that chip and since you'ld be switching within the circuit you wouldn't need any pullup/ pulldown resistors since the signal is within 0 - 9V.

[pott]

That's not really an option... I'm modding a Carl Martin ACTone prototype I have, which sounds a little thin on the high strings right now at higher gain. Weirdly enough the low gain sound is brilliant! So I figured I could convert this one to a dual channel/purposes distortion rather than a straightup AC sound-alike. Amazing pedal but too amp dependent for me I already solved the volume issue (pedal was very quiet) though so it's not that big a deal now. I may just add a LED on pot number 2 and take out one of the shared clipping, to keep it simpler.

EDIT: I just replaced one of the transistors used for clipping by a LED. It's not great yet...It'll take some experimenting. I'm glad I solved the volume issue but I do want it to sound a bit thicker... Maybe 4001s are the key there...