Getting the Headrush Expression Pedal to work with Rack Helix and Controller - without modding the expression pedal

[sevente_jones]

So, I purchased a Headrush Expression Pedal for my Helix Rack - I went with that over the Mission one because I feel that the Mission one is overpriced for what it is and I like that the Headrush has the jacks at the top of the pedal.

I saw another user on here was using Headrush expression with a Helix so I was 'cool, OK, it works'.

 

But when it arrived I found that it was getting the 0-100-0 sweep problem. I tried different cables, TRS, TS, TRS and TS joined with a dual female 1/4", and a TRS to TS Y-cable - all had the same issue. Bummer.

 

I looked up the problem online and found there were lots of expression pedals that had this issue. The main solution seemed to be mod your expression pedal to work with the Helix.

 

I asked the Headrush pedal about this and its response was [see attached file]

 

So I set about finding a solution that wouldn't involve modding the brand new Headrush expression and voiding my warranty in the process - while I didn't find the exact solution I did find the info that would help - and I'm sharing how I used it in the hope it might help others either looking at the Headrush expression pedal or having issues with another brand of expression pedal.

 

The post was from jaminjimlp:
Most potentiometers have three connectors; Clockwise, Counter-clockwise, and Wiper. Amazingly, there are multiple different ways these can be wired, all achieving largely the same result, which means yet more variations for expression pedals. The most common expression pedal wiring is to connect the pot to a 1/4" stereo (TRS) instrument jack as follows:

CW — Sleeve
Wiper — Tip
CCW — Ring

An alternative is with the tip and the ring reversed as follows:

CW — Sleeve
Wiper — Ring
CCW — Tip

Yet a third way is as follows:

CW — Sleeve
Wiper — Tip
CCW — Tip

 

What I took from this is that the CW lug is always connected to the sleeve, I didn't need to know how the Headrush was wired, I just needed a cable that went TRS from the Headrush to TS at the Helix, keeping the wire connected to sleeve at both ends and tying the other two wires together at the tip on the TS end. I decided to make my own cable and used a 4 core mic cable - probably overkill as it's not carrying an audio signal, just the resistance but I do like to over-engineer things - and a TRS and a TS jack plug.

 

The four wires were: red, black, yellow and white. I decided to ditch the white so just snipped it off at both ends. Then on the TRS jack I attached the red wire to the tip, the black wire to the ring and yellow to the sleeve. On the TS end I twisted the red and black together and soldered them to the tip then soldered the yellow to the sleeve.

 

Bingo - the Headrush expression pedal is now working as expected.