Any extra ideas for my new distortion design?

[Brisance]

So I will make yet another distortion pedal, any ideas on how to improve this?

EDIT:

Modified the schematic, added a switch to turn the clipping section off as well as fixed the gain pot and added a limiting resistor to limit the gain to 50.

[bluebunny]

I guess that depends on your definition of "improve".   

Did you build it yet?  If not, throw it on the breadboard and give it a listen.

[Brisance]

Did not build yet, I guess I need to buy another breadboard, since the one I have houses a work in progress aliaser :/

[anchovie]

The first op-amp is set up wrong. The drive pot won't do anything gain-wise as you've nothing off the -ve input to ground for it to form a ratio with. It'll just be a buffer with the other half of the drive pot dumping output to ground, and even with drive at max it won't stand much chance of clipping. That's if it passes sound in the first place, as the +ve input is floating rather than biased to ground with a resistor after the input cap.

A bit of tone-shaping always helps in distortions, so it doesn't go all flubby or squeal at high-drive settings.

The charge pump is probably unnecessary as you're intending to set this up as a hard-clipper. Given this topology, I'd say you'd get a quick result by building an MXR Distortion Plus with your MOSFET/Ge clipping arrangement instead of the usual silicon diodes. If you keep the TL072, you can still use the other half as an output buffer if you like, or just tie the inputs to ground and ignore it.

[GibsonGM]

Fix it like Anchovie says, and add a tone control after the clipping section.   See the Dist +.

Want to have fun?  Add a variable HPF before the clipping diodes!

[Brisance]

Oh, darn it, you are right about the pot, my absent mindedness gets me. I'll probably add a switch to the clipping section so it can double as boost. I used the charge pump because I just got them and wanted to experiment with them.

[Brisance]

Fixed these, check original post

[pupil]

i guess i haven't looked at many distortion designs... what do the mosfets do?

[mth5044]

i guess i haven't looked at many distortion designs... what do the mosfets do?

Clipping diodes!

http://www.muzique.com/lab/zenmos.htm

[pupil]

oh duh, don't know what i'm doing not devouring every page of amzfx. thanks!

[Brisance]

i guess i haven't looked at many distortion designs... what do the mosfets do?

well basically they should clip proportionately to voltage so in theory they should clip more softly than diodes. The body diode will be disabled by the 1N60s

[antonis]

You may add a capacitor between R5 and GND to create a high pass filter...
(cap value to your taste..)

Also - if I'm not missing any decimal point - the input high pass filter (220nF and 1M) attenuates infrasonic frequencies..
(you may well make C2's value 10 times smaller - or 100 times to reach guitar frequencies..)