Tyco Para Pedal Build Report

[RickL]

I built this using the schematic and (modified) layout at geofex. I used the bottom layout and I believe there is a mistake. The negative end of C6 is shown going to -9V. I believe the capacitor should be reversed  with the negative going to the junction of R3, R13, etc and the positive going to (+) ground.

***actually I just realized that it should work as layed out, especially if it's wired as normal with negative ground***

In any case I made the change and it works  I used positive ground as in the schematic.

I didn't know what value to use for C3 so I socketed that position and experimented. In the end I couldn't decide which I liked better so I ended up using a spdt centre-off switch to have a choice of no cap, 0.1uF and 1 uF.

I've only had a chance to test it through a smallish battery powered amp but it certainly seems to work all right. The sound goes away at the bottom of the pot travel but I'm guessing if it was mounted in a wah shell that part of the travel of the pot wouldn't be used anyway.

[bluesdevil]

Glad to hear you had success!! I'm planning on doing a wah pedal project, but can't decide on the Para pedal or Colorsound wah. Did you find a dual 10k pot that can mount in a wah shell? That would be the only thing keeping me from building it. I think.

[RickL]

The dual 10k pot I used would not be suitable for use in a wah shell. I think it was supposed to be used as a volume or pan pot in a stereo. If I end up putting it in a wah shell, rather than just using a regular box with the pot on the side and a large knob that I can operate with my foot, I'll have to use a bigger value pot with parallel resistors to lower the value.

I have had some luck with transfering the wafers from single to dual pots. You need to find a suitable dual pot where the same manufacturer also makes singles with the same size wafer. I make up the odd valued dual pot in an Ibanez wah that way once.

[bluesdevil]

I forgot about the option of throwing a big knob on the side of the enclosure. I can get a 16mm dual 10k that should be fine for that.... also have one of those rubber MXR knob boots to put it on it. I'll give it a shot!!
       Antique Radio Supply (?) has a 24mm 100k dual log pot with a shaft that can be cut to wah length. With the parallel resistors maybe that would be workable for a wah type operation. I don't know how the resistors will affect the log taper, but maybe worth experimenting with if swapping wafers can't be done.
     Thanks for sharing your experience with this build..... gave me the encouragement I needed.