Korg Delta CV & Volume Pedal Hack

Control Voltage and Volume Pedal hacked from dead Wah.

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I found a half-dead Crybaby Wah in the street and converted it into a CV and volume pedal using mostly what I had laying around. I was able to reuse the jacks and pot from the original circuit to pretty nice effect. The pedal has switches to change between Volume and CV modes, with the ability to supply both 0V to 5V and -5V to 5V standards of control voltage. This means I can control the Filter Cutoff on my Korg Delta or use it to control other CV equipment that uses 0-5V instead. The Volume control is a very simple passive bleed to ground like a Guitar Volume pot.

I had this cool wah pedal kicking around for a while and I recently finished restoring a Korg Delta that accepts CV input to control the filter, so I decided to make a circuit to use the foot pedal for this. I had pretty much all of the parts laying around my house and I only needed to purchase one component for the circuit. I drew the schematic up in KiCad, which is awesome and open source, and then made the circuit using perf-board and leads. I was able to salvage the original jacks which help hold the board in place over a piece of pink shipping foam for tension/insulation. I can power it with my 9V Voodoo Lab power supply.

When I found the pedal it was missing the bottom plate so I cut a new one out of these sheets of plastic I found.

One important consideration for the operation of the circuit was the Taper of the pot used to control the output voltage. The original pot is a Dunlop Hot-Potz-II which uses an "S"-taper. See this page for a good comparison of Pots. At the moment it seems usable however I am going to keep an eye out for one with a smoother taper. Ideally, it would be best to have an Audio or Log Taper for Volume and a Linear one for CV, but I am not sure of an easy way of accomplishing this.

Pretty simple circuit, see schematic and partslist for details!

Thanks for Looking!


  • 1 × LM7805 Regulator for generating +5VDC
  • 1 × ICL7660 Regulator for generating -5VDC
  • 4 × 10 uF 25V Capacitors For noise reduction
  • 1 × 1N4007 Diode Reverse current protection
  • 1 × Dead Wah Pedal Chassis, Functioning pot and treadle assembly The hardest thing to make evar

View all 15 components

  • Project Completed

    Scissorfeind07/05/2015 at 01:56 0 comments

    I have been passive collecting these parts for a few months and I decided to put it all together this weekend. Not a lot of complicated stuff in here, mostly just sawing away with the Dremel.

    Here is the circuit I used:

    I have a video of the thing in action, but I dont feel like hosting it anywhere right now. If y'all really want I'll upload it.

    Thanks for looking!


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