Converting Crybaby Wah to expression pedal - change pot?

  • I've got an old Crybaby wah-wah pedal which I recently tried to fix by changing the pot - didn't make any difference, so problem must be with circuit board. However as I now own a Kemper, I'm thinking is makes more sense to convert it into an expression pedal rather than fitting a new circuit board.


    Have found this guide here, seems the only thing I'll need is a TRS jack: https://www.strymon.net/strymo…our-own-expression-pedal/


    However I also found an old thread on here where a few people suggest replacing stock pot with a "10K linear" pot: Expression pedal for wah


    The pot I recently put in my wah was this one (Dunlop Hot Potz II 100k):

    https://www.amazon.co.uk/Dunlo…otz&qid=1580648883&sr=8-1


    I'm not sure what the difference is between this one and a "linear 10k" pot - and seeing as you can calibrate the range of the expression pedal within the Kemper, does it really matter? Or is the problem not so much the range , but that the Hot Potz II has a non-linear response (i.e. that would be curved if plotted on graph)?

  • Yes, I understand, but the question is: is the "Hot Potz II" definitely non-linear?

    I don’t know anything about the Hot Potz II. If it’s like other wah-replacement pots it will be an audio taper.


    Using it for expression will give a throw that does next to nothing for most of the travel. You’ll get all of the sweep in a concentrated area making it difficult to control.

    “Without music, life would be a mistake.” - Friedrich Nietzsche

  • Thanks guys, sounds like the pot'll need replacing then (hot potz II is indeed a standard crybaby pot replacement made by dunlop) - I'll test with a multimeter tho to be sure.


    Have just read up a bit more on pots - can anyone anyone confirm it's definitely a "10K linear taper" one I need? If so, I've found these on amazon/ebay for a few quid :)


    btw - I'll presumably need to remove the cog/teeth attachment from the wah's pot and put it on the linear one - any tips on how to do this? Looks like it's glued on...

  • Thanks guys, sounds like the pot'll need replacing then (hot potz II is indeed a standard crybaby pot replacement made by dunlop) - I'll test with a multimeter tho to be sure.


    Have just read up a bit more on pots - can anyone anyone confirm it's definitely a "10K linear taper" one I need? If so, I've found these on amazon/ebay for a few quid :)


    btw - I'll presumably need to remove the cog/teeth attachment from the wah's pot and put it on the linear one - any tips on how to do this? Looks like it's glued on...

    100K will work if it is a linear one. I did this with an old fender pedal. I think WAH pedals are working with linear tapper Volumne Pedals are working with Audio (log) Tapper.

    But if it's not linear try this
    https://www.musikding.de/Dunlop-10k-lin-Potentiometer_1


    maybe you can also try this but measure first your shaft because there are metric and inch type,

    https://www.ebay.de/itm/16mm-F…m:m89IvhYGDELdvapYptahZow

  • Just FYI I did the conversion but didn't change the pot....its not that bad. Suggest you try it first before splurgging on a new pot..


    Its a bit on and off but to be honest that's how I tend to use my wah anyway - I think crybaby's are a bit like that...not massive linear or progressive,

  • The bigger problem (at least in my experience) is the poor mechanical tolerance of a CryBaby as compared to a Mission pedal. When you go heel-down on a Mission pedal, it stays at that position. Dunlop pedals tend to fall forward a bit when you remove your foot. This leads to the wah activating when you don't want it. I was able to minimize this problem by cranking down hard on the tension strap that runs over the pivot, but it still happens from time to time.

  • I just built an expression pedal with a used Dunlop wah.


    It was actually in PERFECT shape and could have passed as "new"...the previous owner didn't even take the plastic off of the bottom and front logo. -Nicer than both of my wahs, but they're both custom and I didn't want to convert them.


    I used the 10K linear Dunlop pot that came with the gear and washers attached. I also bought a momemtary SPST footswitch and added a stereo jack for the expression pedal out. Lastly, I used a 1k ohm resistor on the wiper of the pot. I prefer to use a switch instead of the toe or heel position to switch off the wah, which avoids any issues despite the fact that my Dunlop wah pedal stays at the heel position on its own.


    It works great and has the right feel!


    $30 used pedal, +$20 parts, +$10 stereo cable = $60 "Mission EP1-KP".


    If I wanted to get really fancy I would have bought a can of green paint....

  • Sounds like a plan! Thanks for the info. As I've already got a (faulty) Crybaby, should be even cheaper :) Will order a 10k linear pot from either the link someone gave further up the thread, or have found some on ebay for similar price (also with gear and washers attached). I guessing you ordered yours from within the US?


    By the way, how did you wire up the footswitch to have it work as on/off switch?


    And am I right in assuming you swapped the footswitch because the one in there originally is a latch switch, and the Kemper's wah on/off function requires a SPST?

  • Sounds like a plan! Thanks for the info. As I've already got a (faulty) Crybaby, should be even cheaper :) Will order a 10k linear pot from either the link someone gave further up the thread, or have found some on ebay for similar price (also with gear and washers attached). I guessing you ordered yours from within the US?


    By the way, how did you wire up the footswitch to have it work as on/off switch?


    And am I right in assuming you swapped the footswitch because the one in there originally is a latch switch, and the Kemper's wah on/off function requires a SPST?

    The footswitch was latching on/off (not momentary) so I replaced it w/ the non-latching momentary switch. You just wire the two leads to a normal (mono) jack. One goes to the sleeve, one to the tip (doesn't matter which one goes where) and you can use a regular guitar lead to plug into the Kemper or the remote.


    For the expression pedal, you need a stereo jack, the 10k pot, and a 1k resistor. I just wired it per the Strymon instructions. https://www.strymon.net/strymo…our-own-expression-pedal/



    Yes, I ordered from the US:

    https://www.tubesandmore.com/p…ometer-dunlop-10-k-linear


    https://www.tubesandmore.com/p…t-solder-lugs-soft-switch


  • Ah, OK, the switch has it's own jack/lead - I'd understood you were wiring it all up to the stereo jack somehow. Can just use one of the existing jacks for the switch then. Will definitely do this, as I agree, a switch on/off is worth having.


    Thanks for the links btw - I should be able to order my parts from the UK, but these will be a good reference to to make sure I order the right parts.


    OK, looks like I'm set to go, should get a chance to source/order parts over weekend. Oh, and I'll also need some wire, but looked this up and apparently 22 gauge stranded wire is ideal, can get this cheaply too if can't find any lying around.


    Will report back when I get it working!

  • Thanks, just placed order on the final bits! The hardest thing to find was the TRS jack - most of them seemed to fit 11mm mounting holes, and the ones on the crybaby are 9mm. Anyway, think I found one that looks right, an open body one (like on most guitars, but stereo).


    Advice on all these components much appreciated - the "how-to" guides are all a bit vague on specifics... If only Radio Shack or similar still existed, would have been much easier to get all this stuff! In the UK at least, electronic components stores only seem to exist online these days.

  • Got it built today, works perfectly! Pic below. Used a bit more wire than was strictly necessary, but that enabled me to solder wires to contacts with the parts out of the case then just connect the wires in the middle once all in place. Didn't put in a footswitch for now, as have also ordered a 2-button footswitch (to scroll thru profiles, control looper etc) and I'll need the other pedal jack on the Kemper for that.


    One other question - when setting up pedals in System menu, you can choose "pedal type 1" or "pedal type 2" - have just left it on 1 for now - can't find these settings mentioned in manual, what's the difference?


  • From the manual page 122:

    “Pedal Type 1” is also preselected, which fits nearly all regular expression pedals. If you are using an expression
    pedal with reversed polarity (e.g. Yamaha™), please select “Pedal Type 2”. Wrong polarity could cause a suboptimal response curve.


    So if you select type 1 and in calibration you see that is goes in then wrong direction heel pos 100 toe pos 0 .


    By the way ...
    please shorten the wires and solder the resistor directly to the potentiometer. The wires fall around in the case and will break. They are also much more sensitive to electrical interference. And you don’t need to tape the soldering points with insulating tape.