A different/easier way to use the Tychobrahe Parapedal circuit

[Paul Marossy]

I have created a Frankenstein Wah. 😆 I abandoned the Colorsound Twin-T circuit (aka inductorless) that I just couldn't get to perform like it should and replaced it with the Tychobrahe Parapedal clone instead - it works great!

I think I built my Tychobrahe Parapedal clone using the GEOFEX negative ground version layout back in 2006. Used a couple of salvaged JRC4558s in it. I've had the circuit sitting in a drawer for a very long time because I wasn't happy with the dual pots I tried to use... just never was quite right. I simulated the Parapedal in LTSpice for fun this week, to see what frequency range it ought to have, and then I thought that maybe I should revive the project.

So a day or two later I rewired it with two separate pots because I had a thought that maybe it could make an interesting "Q" pedal. In that process, I also discovered that you can take the second pot in the Parapedal circuit (the one between U2A & U2B) and just leave it in a stationary position. It's kinda like a "Q" control. That also solved a quirk I had where the sound would vanish when both pots were turned all the way CW. The other half of the dual pot can function like a normal wah pedal pot thru the entire range possible, albeit it has to be 10K vs the typically used 100K. This allows me to not have to use an impossible to find 10K dual pot, and now I can actually use my DIY wood & aluminum replica of the Colorsound wah enclosure. It's very vocal and it has a big range too...it reminds me a bit of the Kay wah pedal. I may do a quick video to show how it sounds. It seems to me that it still has same character as the with dual pots. Not quite sure why the second pot is needed

So I guess that I have a sleeper wah now... says Colorsound on the outside but it's a tweaked Tychobrahe Parapedal on the inside! 

BTW I looked at the waveforms on the scope just using the one pot that controls the frequency and I discovered that all it is really doing is generating 3rd order harmonics and changing the phase relationship between the those harmonics and the fundamental. I didn't know what to expect really, but that wasn't exactly it - didn't look anything like any other wah pedals I've looked at with the scope. Anyway, I can replicate these waveforms on my Interactive Fourier Analysis Tool - http://www.diyguitarist.net/Misc/FourierTool%20Only.htm When it came to the waveforms, LTSpice was not able to replicate real world results in this instance.

[theehman]

I did something similar a few months back with my Pair-A-Filter pedal.  Basically, the Tycho as a "set and forget" %^&*ed wah pedal.

[ElectricDruid]

 "Frankenwah", love it!

Carry on.

[Paul Marossy]

I did something similar a few months back with my Pair-A-Filter pedal.  Basically, the Tycho as a "set and forget" %^&*ed wah pedal.

Yes it does work nicely that way as well.

[Paul Marossy]

Quick look at the waveforms: