The mission Ep1 is compatible with the MC6 Pro? When I calibrate it the maximum I get is 122 on my Helix it only reaches 98% which I am missing?
That’s fine, as long as it is calibrated and the values are saved for the toe down and heel down positions, the expression should reach 0-100%.
Are you saying that after calibration, you are still getting only 98%?
That’s right James, I’m only get 98% in my helix native
What range does the MC6 PRO show though, when you move the exp pedal?
If it is 0-100%, can you check the values that are being sent in the MIDI Monitor? What is the range of CC value that is being sent out?
On the MC6 Pro it shows me a range of 0-98% when I move it, and on helix native it shows me the same range when I assign it to the wah or whammy position.
Try twisting the 1/4" plug on both the MC6 PRO and Exp pedal and see if it helps.
We can check the firmware next week.
Another solution would be to just recalibrate, but instead of the maximum toe down value (122), shift the pedal back a little to 120 or something, and then save it.
i have the same problems… but with my Axe FX 3 mk2
hi gain… volume pedal is not 0… when heel down… so you still hear sound…
Calibrated as well.
checked different cables, mission engineering expression pedal, mooer expression, boss f 500 expression…
same thing… hope there will be an update soon… festival season is starting this week…
thanks in advance
@MrMister Try this solution for an immediate fix, it should help.
I just did this a second ago… didn’t work?
Ah sorry, for the heel down position as well. So if your heel down value is, for example, 2, push the value up to 4 and then save the position.
didnt work… midi monitoring was also tripping?!
Ok we’ve worked on the expression functions (calibration + operation). You should re-calibrate after updating the firmware.
Can you try this firmware and let me know how it works for you?
2023-04-03_MC6_PRO_Firmware_v_3_11_2_Expression_Calibration_Fix.hex (1.1 MB)
hi James I just tried the update and I still have the same problem
I tried to adjust as you mentioned instead of 122 I tried several values until I got to 90 and the percentage after calibrating at those values gives me 0-99%.
Can you let me know what expression pedal you are using?
@james mission engenier ep1
Ill let you know. omw to rehearsals with the board.
worked for me! 0 = 0 now… also with high gain sounds
@james I would like to add that when I step on the floor to reach 100% for a very brief moment it marks 100% but ends up being 99%.
Thanks. I experienced this too in the initial firmware and this was what we fixed in firmware I shared. I might need to do some more tweaks. Will test and update tomorrow.
Hi James,
Just did a big festival show, unfortunately 0 wasn’t 0 and I had a lot of “noise” when pressing down my heel to 0…
Also had some banks jump…out of nowhere during the show… not even pressing anything. Sound/ presets changed on my axe fx 3 mk 2…
Not just one bank, but a couple of banks further.
Glad I was using banks, and could control it with my separate aux switches… so I could go back really quick… but it was a hard time on stage !
( it’s just midi in out from mc6 pro to axe… ) nothing else connected
Do you have an explanation for this? Especially volume expression control?!


