MC8 - After Update to v3.11.1A - Expression jumping back and forth 0% and 100%

I just updated my MC8 and now my Lehle Dual Expression Pedals act weirdly:

At the lowest setting (heel down) every now and then the signal is jumping very fast and continuously from 0% to 100% back and forth. Yes I did recalibrate multiple times, checked out all the sensibility options.

When I calibrate and I decide not to go all the way heel down completely, usually from that position to complete heel down should all be 0%, right? When I go completely heel down the MC8 jumps from EXP:0% to EXP:100% and remains at that value.

Thanks so much for your help!

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Can you try this firmware here and let me know if it resolves for you?

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Okay, I used that firmware and now I can make it work again, thanks so much!!!

There’s one thing I have to pay attention to, when calibrating the Lehle Dual Expression. I have to go to the lowest heel value by moving it rather slowly, lowest value I can get is a value of 9, then it works. When I calibrate it to quickly, the lowest value shown is 12. When I calibrate heel at value 12, the lowest setting of the pedal makes it jump from 0% to 100% again.

I’m using the 50k TRS output of the Lehle Dual Expression.

I fear, the problem is the design of the Lehle Dual Expression Pedal - which is supposed to be a high quality piece of gear given it’s retail price. Thanks so much James for helping me!!!

EDIT: Same behaviour with the MC6 Pro (When Calibrating I get a range ftom 1 to 125, if that’s got anything to do with it?)

Are you able to change the potentiometer resistance on the Lehle from 50k to 10k? 10k works best for our controllers.

Experianced similar thing after update to FW 3.11.1.
Issue got sortet out by using the “total end positions” (both up and down) for calibration. It works properly since days (It must be made sure not to override “0” or “100” after the calibration),
My pedal, a rock solid earnie ball, is using a 10k pot.


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This firmware should resolve the issue: MC8 - After Update to v3.11.1A - Expression jumping back and forth 0% and 100% - #2 by james

There is a setting that seems to work better for different expression pedals, that we need to make user editable.

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I also have the same problem with “Firmware_v_3_11_1_Exp_Test”.
My gear are two SP25M-PRO AERO (25K Ohm) in Omniport 3 and 4,
which with “Firmware_v_3_10_2” work perfectly.
I recalibrated several times and checked all sensitivity options.

thanks for the support

how about the original v3.11.1 firmware? Does the issue occur in that as well?

in exactly the same way

thanks for the info. is it possible you share with me a video of the calibration values when you sweep the pedal so I can see what might be the issue?

Like this?

I have the same issue using the expression out of a Boss ES 8.
My setup is Dunlop DVP into ES 8, ES 8 Exp1 out to EHX Pitchfork, ES 8 Exp 2 out to MC 8.
I’ve noticed something interesting. Due to the architecture of the ES 8 I can either use the ‘native’ expression out (Exp in 1 to Exp out 1 or Exp in 2 to Exp out 2) or use both outputs at the same time. Using both outputs simultaneously will cause that flickering bug described by the others, while using the native expression out won’t. When calibrating the expression pedal on the MC I can see a difference for the heel down position value depending on which outputs are currently used. Using the native output will give a value of 20 while using both outs gives a value of 1. This hasn’t been an issue in fw 3.10

Interestingly and unfortunatly if I choose both outs in order to control the Pitchfork (I can control the MC via the native out) the flickering between 0 and 100 occurs on the MC while the ES 8 puts out an expression value of 100% to the Pitchfork in heel down position.

My guess is that Boss uses a simple relay switch to connect the Exp ins to Exp outs and the CV generated by the MC f* up the expression value to the Pitchfork.

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My SP25M-PRO AEROs have 3 outputs, all connected.
I tried to calibrate with only one output connected (first with OUT 1 and then with OUT 2), but f. 3.11.1 (and also f.3.11.1 Exp test) still has the same problem. And as usual f.3.10.2 is perfect.

Thanks for the feedback. I’m currently out of office till 5th May - will get it checked out as soon as I’m back.

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Are there any news about this?

Same flickering problem with a Boss ev-30 into a MC-3 and (2) Saturnworks double A TRS TRS into a MC-8. I could hear the modulation while it flickered.
After calibrating etc. I made the heel down CC#1 instead of CC#0 and that solved it for me. I don’t seem to miss the number.

Thanks for waiting!

Can you give this firmware a try:
2023-05-12_MC8_Firmware_v_3_11_1_Expression_Calibration_Test.hex (443.2 KB)

You’ll need to calibrate your expression pedal. There is a “Set Read Type” option to allow you to select 0 or 1, before setting your Heel and Toe down values. Typically the 0 setting is what you want to use and will work to reduce flickering, but seems like some expression pedals work better with setting 1.

Do give it a go when you have a chance and let me know how it works for you.

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just tested the firmware, unfortunatly it isn’t working for me.
For whatever reason the ES8 is producing different values when calibrating depending on the routing for the expression output. (refer to my previous post for details)
Here is what happens:

I can either calibrate the pedal for scenario 1 (only one output is used), or scenario 2 (both outputs are used.
In scenario 1 I get a value of 20 for the heel down position.
In scenario 2 I get a value of 1 for the heel down position.

If i calibrate the pedal to work in scenario 1 correctly, it won’t cause flickering anymore.
But when switching to scenario 2, the expression value shown on the screen goes down to 0% until a certain point and then jumps back to 100% while moving the pedal into heel down position.

If I calibrate the pedal to work in scenario 2 correctly, it will cause the expression to go to 14% (17% if I choose read type 1) as minimum in heel down position when switching to scenario 1.

My solution would be to calibrate the pedal to work in scenario 1 correctly, but this causes the bug to occure.
My guess is that the MC can’t handle ‘negative’ values for the expression input (I don’t know if this is a thing physically but it would be logically) and bugs out if recieving expression inputs below what has been calibrated for the heel down position.

For now I’ll revert back to Firmware_v_3_10_2 works fine with that.

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If in v3.10.2 it worked then we should be able to get it to work. Odd because the only change we did related to the expression read can already be set with the “read type” setting in the new firmware.

I’ve got an ES5 in office - let me try to set it up next week to test.

Just to add, the Boss EV-30 works perfectly 0-127 in my setup into an MC8. The sensitivity is set to medium and calibrated through the online app with firmware standard v3.11.1. Appreciate that doesn’t necessarily help the others with issues.