parapedal mod

[9 volts]

Just wondering how I would go about adding a mod to a parapedal to alter the depth? Any suggestions? Thanks

[slacker]

Not sure exactly what you mean by the depth, but here's a couple of things to look at.
If you change the 0.068uF caps that changes the frequency range the pedal sweeps over. If you make them both smaller the frequency range moves upwards so you lose the lower frequencies, but if you just make the second one (the one nearest the output) smaller then it just moves the upper range of the sweep upwards so you get a wider frequency sweep. I've got a 0.022uF in mine at the minute and that gives a really nice sweep.
You can also play about with the values of the 2 10K resistors in the feed back loops raising these increases the amount of  "quack" the filter has, but if you go too far it distorts and will probably self oscillate.

[9 volts]

Thanks, by depth I meant what is normally called q (eg Q resistor in a standard wah). I was looking to add a pot to have the option of making the 'q' more subtle. I'll try a dual pot for the two 10k resistors. Thanks again, I'll keep you posted

[slacker]

you might not need a dual pot, just changing R12 on the Geo schematic into a pot might be enough. That works on the MXR envelope filter which is a similar circuit.