Inspired by Aron's presence controls I tried putting a reverse connected stereo pot in both filter legs.
Simulation in tone stack calculator showed with these values below a sweep from notch to slight boost with the same center freq.
The one knob presence control shifted the frequency a bit.
Tone pot is still 100k.
(https://i.postimg.cc/v1hhGJQZ/big-muff-tone-mod.jpg) (https://postimg.cc/v1hhGJQZ)
There is a lot of boost of the entire signal when mid-bumped. Should push both recovery stage and amp plenty.
I'm not sure what are Aron's presence controls so this might be something that's done already. (Familliar with Jacks ones though: http://www.muzique.com/lab/tone3.htm)
Anyway... How about reversing one of the pots in the stereo pair to get a moveable notch/center frequency?
I see problems for using an active equalizer on an op-amp. The last gain stage restores the volume loss after the EQ. it does not distort the signal, but gives a pure gain, which means there will be no difference between it and the op. You can use an active EQ for the mids and an active tilt control like a diamond compressor. you can use the active equalizer for 3 or more frequencies.
Quote from: stonerbox on May 31, 2023, 06:13:40 PM
There is a lot of boost of the entire signal when mid-bumped. Should push both recovery stage and amp plenty.
One can place the level pot in front of the recovery stage or lower its gain :icon_mrgreen: