[Solved] Expression pedal help

[Lance Holland]

Hi!
I'm trying to set up an expression pedal as a wah. I've gone through the configuration but when I calibrate the pedal, the slider only moves a little from the left (5% of the way or so). It does work as a wah since I can hear it but there's very little range. Thinking it might be the pedal, I tried another expression pedal that I user with an Eventide H9 and it does exactly the same thing. I've fiddled with the settings on the wah block but that doesn't seem to help the range.

What am I doing wrong?

L-

 

[chris]

Hi!
I'm trying to set up an expression pedal as a wah. I've gone through the configuration but when I calibrate the pedal, the slider only moves a little from the left (5% of the way or so). It does work as a wah since I can hear it but there's very little range. Thinking it might be the pedal, I tried another expression pedal that I user with an Eventide H9 and it does exactly the same thing. I've fiddled with the settings on the wah block but that doesn't seem to help the range.

What am I doing wrong?

L-

You haven't told us what pedal you use. Can't help much. Also, are you using a TRS cable or a regular instrument cable?

 

[paranoid]

are you connecting it with a trs cable? what type of expression pedal is it?

 

[Lance Holland]

Both pedals are mods that I've used for a while. One is a Nose that I rewired as an expression pedal. The other is an Ernie Ball volume pedal modded into an expression pedal. Both measure 10 ohms on my multi-meter.

 

[chris]

Both pedals are mods that I've used for a while. One is a Nose that I rewired as an expression pedal. The other is an Ernie Ball volume pedal modded into an expression pedal. Both measure 10 ohms on my multi-meter.

what about the other question?

 

[Lance Holland]

Yes - it IS a TRS cable. (the same one I've used with the H9)

 

[Rex]

Yow. 10 ohms? Something's not right. It should read at least 10,000 ohms.

 

[chris]

the slider only moves a little from the left (5% of the way or so).

this typically means the pedal or cable isn't wired correctly, or at least for what the FX8 is expecting. there are a few different standards for expression pedals.

 

[Lance Holland]

this typically means the pedal or cable isn't wired correctly, or at least for what the FX8 is expecting. there are a few different standards for expression pedals.

Nope - the expression pedals both work fine on my Strymon and Eventide pedals.

guess Fractal needs to see more ohms for the expression pedal?

 

[chris]

Both measure 10 ohms on my multi-meter.

10 ohms? or 10 k (10,000) ohms?

 

[Lance Holland]

OK....I went back and re-measured both pedals with my multi-meter. They're actually reading 10K ohms.

 

[chris]

from https://missionengineering.com/understanding-expression-pedals/?v=7516fd43adaa

"3. Wiring.
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

In this last one, the wiper and CCW are bonded together and connected to the tip and the ring is unused. This requires the use of a mono (TS) cable such as a regular guitar cable, in place of the stereo (TRS) cable used in the other two. These three are the most common that we see in expression pedals, but we keep finding more. Sometimes a dual gang potentiometer is wired in parallel to create a single pot with half the resistance. For example you may see a dual 20K Ohm potentiometer bridged into a single 10K. In this case the pedal will function the same as if it were a native 10K Ohm single pot.

The most unusual configuration we have seen appears to be the original Univibe speed control pedal which looks like it used a dual gang 100K Ohm log pot with the wipers bridged together and connected to the ground. It would be interesting to find out what the story is behind how that came about. There are some Univibe clones on the market that require a similar type of wiring.

An expression pedal with wiring polarity that matches the equipment specifications is required. Using a pedal with incompatible wiring can result in limited range, jumping or notch like response, or the pedal just won’t function at all, so make sure you check the requirements of your equipment. It’s often listed in the User Manual."


how do you have yours wired?

 

[Lance Holland]

I'd have to tear them apart to figure that out. It doesn't make sense that they both wired wrong - they work fine with other products.

 

[chris]

I'd have to tear them apart to figure that out. It doesn't make sense that they both wired wrong - they work fine with other products.

as i mentioned, your other products might be compatible with one of the other methods of wiring. the same expression pedal won't work on every piece of gear out there. as i posted, there are at least 3 ways of wiring, and perhaps the way you custom wired your own pedals isn't compatible with the FX8, but it is compatible with your other gear.

no sense tearing them apart. i'd just buy a dedicated expression pedal, probably starting around $40 or less.

 

[Lance Holland]

I'll check into it in the morning and report back!! Thanks for the hints.

 

[Lance Holland]

Welllllllll. I'm truly embarrassed. After pulling my hair out (or what's left of it), I decided to try the expression pedals with my H9 and they DIDN'T work!

It turns out that in removing the TRS cable from my old board, I somehow broke the cable. I plugged a new TRS cable in and low and behold, the expression pedals both works fine with the FX8.

So sorry for troubling everyone!

 

[chris]

Welllllllll. I'm truly embarrassed. After pulling my hair out (or what's left of it), I decided to try the expression pedals with my H9 and they DIDN'T work!

It turns out that in removing the TRS cable from my old board, I somehow broke the cable. I plugged a new TRS cable in and low and behold, the expression pedals both works fine with the FX8.

So sorry for troubling everyone!

it's usually the cable in these situations. glad it's remedied.