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Wicked Wiki 18: External (S)witchcraft



“External (S)witcraft”

The MFC-101 lets you connect up to 4 external switches, using its two switch inputs (XS1+2, XS3+4).

1 — Connecting
You need a TRS cable (stereo) to connect a dual switch to each input.
When connecting a single switch, you can use a TS cable (mono) instead. In this case set the 2nd switch in the MFC-101's configuration to OFF to prevent issues.
For more information about cables, see chapter 8 of the MFC manual.

2 — Purpose of external switches
Players use external switches to extend the functionality of the MFC-101. These switches are used to engage/bypass effect blocks, to switch effects between X/Y, to select preset scenes, to tap the tempo etc.

There are limitations:
  • When using an external switch to activate the Axe-Fx tuner, the tuner will be displayed on the Axe-Fx screen only, not on the MFC.
  • External switches can be used only to send a MIDI Control Change (CCs), not a Program Change (preset change).
  • Only a single CC only can be sent, as opposed to the MFC’s onboard switches which support send two CCs.
External switches operate globally, across all presets. But you can override them per preset, through EDIT > PRESET.

3 — External hardware switch types
You can use either latching switches or momentary switches.

  • Latching aka “toggle” switches, are like stomp boxes: press once to engage, press a 2nd time to turn it off.
  • Momentary aka “hold” switches are like keyboard pedals: press and hold to engage, let go to switch off.
You must inform the MFC about the hardware switch type(s) you are using: EDIT > SETUP > XS.

4 — Programming external switches through MIDI
External switches control stuff through MIDI: EDIT > MIDI > XS. Here you select the MIDI channel, the specific CC the switch will be sending, and the values for ON and OFF. To get a list of all Axe-Fx CCs, go to I/O > MIDI > CTRL on the Axe-Fx.

The CC values are 127 and 0 by default. These can be changed, i.e. when using the switches to select scenes.
Note that you can set them to OFF as well. This is handy for example when assigning a momentary switch to Tap Tempo, where you want only the press to count, not the release of the pedal.

5 — External switch behavior
Telling the MFC what hardware is connected (see above) is one thing. How you want those switches to operate, is another. This is especially important for their behavior when changing presets.

The MFC lets you choose between 3 “types”: HDW, TOG and AUT. Page 59 in the manual lists the different types in a handy table.

5a — TypHDW (Hardware Follow)
This means that the MFC will treat the switch according to its hardware type. So: a toggle/latching switch will act as a toggle switch, and a momentary switch will act as a momentary switch. What's really important here: selecting HDW means that the MFC will always “poll” the switch state when changing presets.

Example: you pressed toggle/latching switch 1 (“HDW”) engage the wah. You recall preset 2. The saved state of the wah in this preset 2 is bypassed. But, because the MFC polls the switch state after changing presets, the wah will be engaged.

This will often be desired behavior, because it’s similar to how a traditional pedalboard operates. And if your switch has a LED< it'll always be in sync. On the other hand, if you like the approach where you want your presets to determine primarily which effects are engaged, polling may not be desired.

5b — TypTOG (Act as Toggle)
The consequence of selecting this option is different for latching/toggle switches and momentary switches.

  • Latching
    When setting a latching switch to TypTOG, it will still operate as a latching switch (same as HDW). However, the MFC will not poll the switch state when changing presets. In other words: the state of this external switch will not overrule the saved states of the blocks in the recalled preset.
    So this seems like a good solution when you like to run in Axe-Fx mode, where presets are in the lead. There’s a downside though: the lack of polling means that the MFC/Axe-Fx may require re-syncing with the switch state. Example: You have pressed toggle/latching switch 1 (“TOG”) which engages the wah. Without bypassing the wah you recall preset 2. The saved state of the wah in this preset 2 is bypassed. The MFC doesn’t poll the switch state so the wah stays bypassed. You want to engage the wah and press the external switch. This will not engage the wah though; the MFC still thinks the switch is ON so now switches it OFF. The wah block in the Axe-Fx was already off so nothing happens. Only when pressing the switch a 2nd time, the wah will be engaged and the Axe-Fx / MFC / external switch will be synced again. This is of course a handicap. Solution here is to press the switch before changing presets to keep things synced but this requires thinking ahead.
  • Momentary
    When setting a momentary switch to TypTOG, it changes from being a momentary switch to a simulated latching switch. This lets you turn a “keyboard” pedal into a stomp box.
    This also prevents the MFC from polling the switch state when changing presets. The state of this external switch will not overrule the saved states of the blocks in the recalled preset.
    There’s the same downside: when changing presets the Axe-Fx/MFC/external switch may lose sync, requiring the switch to be pressed two times to sync again.
The syncing issue also means that any LEDs on your switches also won’t be in sync with the switch state anymore.

5c —TypAUT (Auto Off)
The manual states that this mode sends an ON message quickly followed by an OFF message and that this is required to control some MIDI equipment. This will be interpreted as an ON command by the receiving device.

You won’t need this in many cases. But it seems to be handy in this scenario: you need a switch that changes an effect from X to Y. You don’t want:
  • a toggle switch that overrules your preset configuration (latching > TypHDW)
  • a toggle switch that may lose sync (latching > TypTOG).
  • a momentary switch which requires pressing and holding (momentary > TypHDW)
  • a momentary switch, acting as a toggle, because it may lose sync (momentary > TypTOG)
So what can you use: a momentary switch, set to TypAUT. Somehow the MFC will not process the OFF command. So this will switch the assigned block from X to Y. The state will not carry over to other presets (not overrule the saved sate of preset blocks) and will not lose sync. But it won’t let you change back to X; you need to recall the same preset again to do that.

EDIT: forget it. This method is not reliable. Sometimes the MFC won't process the OFF command, at other times it will.

6 — Resuming
There's a lot possible using external switches, but there are caveats too to be aware of.

Note that the challenges described above, deal with external switches assigned directly to effects (through their CCs).
There's also the option to assign external switches to the CC of external controllers, where the modifier menu is important as well.

MFC-101 Tips

List of all Wicked Wiki threads
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Thanks Yek! As always, your work is appreciated. I'm setting up a few externals for tap tempo and x/y states soon, and this will really help!


Power User
I am thinking of using Roadrunner's external switches to control the rotary X/Y states (i.e., to toggle between slow and fast speeds). Tips?


Power User
I am thinking of using Roadrunner's external switches to control the rotary X/Y states (i.e., to toggle between slow and fast speeds). Tips?
I'm not offering a tip, but I will pitch my $0.02 on rotary control... I have always preferred to have the rotary speed assigned to continuous controller, rather than just X/Y between two settings. Sometimes I want to finesse the ramp rate between the rotation speeds for effect, either making an exaggerated slow transition, or arriving more quickly. I also like being able to sweep to (and stay at) a rotation speed in between the slowest / fastest rates, which isn't possible with an X/Y approach.
I recognize this isn't the behavior of a true Leslie speaker. I've actually played / recorded with real Leslies, and they're fabulous. I just always felt it would be useful to have true continuous control over the rotation speed. I use the rotary effect more than any other effect, even for 80s style material where a CE2 chorus effect would be considered more idiomatically "correct".


Power User
Thanks Sleestak - aside from playing on a friends Leslie through his Hammond B3 during the '70s, I'm pretty much a total newb at implementing and managing configurable rotary effects. :encouragement:

How are you implementing the triggering of continuous controllers for finessing the ramp rate of the rotary effect?

Automatically through an IA switch(es) or manually through an expression pedal?

Edit: thought it through and consulted with Mark - an expression pedal offers the best real time control over changes in the rotary rate and is in sync with the particular musical expression and the beat of the band. Thanks again for your help Sleestak :)
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Power User
I always use the continuous control of an expression pedal for this. It's certainly possible to set it up with fast / slow controls too, but I like being able to adjust the speed to any point in the range.
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