Expression pedal bug MC8

Peculiar thing happening here with the expression pedal.
I am using the latest editor/firmware
The expression pedal is live talking to a fader. However, it only emits values in the range of 62-99.
No matter, where I set the values, it’s fixed.
Can’t set the range to 1-127.
I can’t believe, spent an hour on this shit. Arrrgggh

Also worth mentioning that Toe Down / Heel Down has no effect.
It only emits messages Expression Linear/Custom.

How can something so simple be such a chagrin?

Can you share a screenshot of your expression preset settings in the editor? Also, what expression pedal are you using? Did you calibrate it in the controller?

Hi James,
Thanks for your response.
Attached are the two use cases I got for the expression pedal.
I don’t see how I can calibrate the expression pedal in the manager app, beyond assigning input types.


What expression pedal are you using? Are you using a TRS cable to connect the expression pedal to the controller?

The calibration currently needs to be done in the controller itself. More info in the manual here:

yes TRS cable. it’s a behringer expression pedal.
it works with elektron gear directly without a hitch.

I am calibrating now… will report in a minute.

However, heel down won’t go below 2% and toe down gives a wobbly 93-100%
shouldn’t they be absolute?

Is it this one? Behringer | Product | FCV100

Looks like it features a potentiometer which varies eg minimum volume in heel down position. Have you tried calibrating the expression with that turned 1) fully clockwise 2) fully counter clockwise?

The manual seems to indicate that control of expression (as opposed to volume) relies on the Exp pedal’s switch being set to ‘CV’ and Output 2 being used…

MC manual states “10k ohm linear potentiometers give the most accurate and smoothest response, though 10k - 25k ohm linear potentiometers will work too. Log potentiometers will not work well.” So it may be that this Exp pedal is not a type that will work well with an MC?

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Yes, most expression pedals are 10K linear, and that’s what the MCx works best with. If the potentiometer resistance is too high, the MCx will not be able to read the voltage properly, which results in jittery reads. The only solution would be to reduce the expression sensitivity. More info in the manual here.

From the manual, it looks like the Behringer is using a 50k potentiomter. Also, the Tip and Ring wiring is swapped, unlike most other expression pedals where the tip is connected to the potentiometer wiper.

Here’s how most expression pedals are wired (without the 1k resistor) (taken from Strymon Tech Corner #1 - Anatomy of an expression pedal - Strymon):

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thank you gentlemen,
for explanation and leading me out of the hole.
I can confirm that after calibration and setting the sensitivity low, i can get by!

the potentiometer setting on behringer makes absolutely no difference.

I looked up on and they don’t give specks for an expression pedal by this criteria “10K linear”. Is there a particular brand that you recommend?

Good stuff! Unless a manufacturer publishes the type (log/linear) and the resistance of their Exp pedal there’s no way of knowing (unless you buy one and run a multimeter over it of course!) lists some known to work exps - personally I use the m-audio pedal which was cheap when I bought from Amazon, like around £13 UK!