I have a Fuzz pedal for my bass and I would love to be able to control the Fuzz level with a (wah-like) pedal instead of bending down and turning the knob with my hand.

I am thinking of one of the two following possible solutions:

  1. a purely mechanical solution where I could link the rotation of the pedal over a X/Z axis to the rotation of a knob over the Y axis

  2. reroute the rotary control form the knob to the pedal.

Is any of that feasible ? Or is there an easier way ? If so, what do I need in order to build it ? I'm completely lost here and don't know where to start

  • 1
    You need to start smaller and build some pedals from kits. You’re asking about making modifications to the electronics inside the pedals. And you won’t be able to do it the same way for different pedals. Apr 5, 2018 at 19:04
  • Well I figured replacing a rotary control by another wouldn't be too hard
    – Mouradif
    Apr 5, 2018 at 21:38
  • I think something all-mechanical might be possible by using a bicycle brake cable. Need some kind of ring assembly to turn linear motion into rotary motion. Dec 4, 2018 at 17:41

2 Answers 2


If you just want to be able to give the control a tweak with your foot now and again, rather than needing to 'ride' it, the simplest solution is probably an option knob:


If you really want to be able to use an expression-pedal-like controller, you'll need to modify the pedal so that the part of the circuit that was routed through the potentiometer is routed out to a potentiometer providing a similar range of impedance in a (custom-built or modified) foot controller. It won't usually work with an off-the shelf expression pedal, and as Todd says in the comment, you won't be able to re-use the same expression pedal for different controls on different stompboxes.

I'm sure a mechanical solution would be possible too, or an electrical solution using a small motor (both of which could then be more generally usable with any knob on any pedal), but I'm not aware of anything available off-the-shelf and as a custom build I imagine they'd be harder to make than the custom expression pedal solution.

If you're really interested in getting a lot of realtime control under your feet, it's possible that you might want to look into using a configurable multi effect box, rather than traditional pedals.


It's easy to do. You just have to figure out what type of pot you want to control is and to be able to fit another input. An 1/8 inch stereo input/output socket will do the job best as space restrictions will be lifted and you won't confuse the inputs ever. Then you have to modify your wah pot with resistors to the value you want to control. Connect a wire to each of the pot's lugs. Connect left lug to the input's tip contact. Then the middle one to the shaft, then the last one to the other one. You can find on the net how to modify an old crybaby or vox wah into an expression pedal (somewhere else, I forget where), but trust me you'll find it then connect a cable to each and there you have it. Make any pedal express it self with one of your bottom hands.

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