Help with external footswitch controller

Discussion in 'The Projects Forum' started by MichaelDimanno, Apr 13, 2015.

  1. MichaelDimanno

    Thread Starter New Member

    Apr 13, 2015
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    I am modifying a guitar multi-effects unit for external switching of presets. The external footswitch uses 2 spst momentary switches and a trs cable. The problem I am having is on the multi-effects side.
    The footswitches send either tip and sleeve or ring and sleeve, meaning that sleeve is always sent.
    When I detach the sleeve connection from either of the buttons in the multi-effects unit the other button works correctly and vise versa. I am wondering if i could use a relay on the sleeve connection. I have attached a diagram of what is going on any help would be much appreciated.
     
  2. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    First off, you're not sending eg.the sleeve anywhere (I hope), but are connecting sleeve to either of the other two.
    Not knowing what goes on inside your FX, it is hard to say what's happening, as it sounds like it's wired how it should be - could it be that it has to go open to signal a change?

    According to what you write, a solution would be to get double pole momentary switches and switch the sleeve signal along with the tip or ring.

    If you can post a schematic of your FX, at least the part that receives the momentary signal, it would be easier to help.
     
  3. MichaelDimanno

    Thread Starter New Member

    Apr 13, 2015
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    0
    Soren,
    Thanks for the reply. I agree that using dpdt switches for the external switching would probably work but unfortunately I cannot as the external footswitch also sends midi messages to another unit and I really dont want to mess with it.

    As for the effects unit schematic I have not been able to find anything on lne that could help me.

    The effects unit switches do two things, when pressed separately they increment or decrement the patches. When they are pressed together they put the unit into tuner mode.

    I can get each of the footsitches to work separately one at a time but when I hook them both up pressing either external footswitch puts the unit into tuner mode, meaning they are both being activated at the same time.

    So close but so far away.
     
  4. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    I'm not quite sure of what you're trying to connect - is it an FX that you put some connectors in bridging the existing buttons?
    And the pedal sending MIDI would be a ready made device?
    Please post make/model of both.

    The more info you can post the nearer we can get you :)

    The reason that you have to disconnect the sleeve may indicate that the buttons in the FX may do more than just making a contact - perhaps it breaks a connection as well, but I'm shooting blind here, as I don't have enough info.
    So, please describe your setup more.
     
  5. eetech00

    Active Member

    Jun 8, 2013
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    What is the make and model number of the effects unit?
     
  6. MichaelDimanno

    Thread Starter New Member

    Apr 13, 2015
    4
    0
    The effects unit is the vox tonelab st, and the external footswitch is the amt fs-2midi.
     
  7. MichaelDimanno

    Thread Starter New Member

    Apr 13, 2015
    4
    0
    I think you are right about the buttons also breaking a connection. When both are pressed together the unit enters tuner mode the when either of the buttons are pessed the unit exits tuner mode back to preset mode. I think thats where the break happens.

    The effects unit is the vox tonelab st and the external footswitch is the amt fs-2midi.

    Thanks
     
  8. Søren

    Senior Member

    Sep 2, 2006
    472
    28
    As far as I can see, that particular footswitch does...
    Seems like it does that in all modes, so entering tuner mode from the FS2 maybe won't happen, but I could be wrong.


    Where on the ToneLab do you connect the lead??
    I cannot find a TRS connector for this - did you add one (or repurposed another existing) connector?

    Do you own or have access to a multimeter?

    BTW. the PCB mounted switches in your drawing looks odd. Usually it's the middle pin (of each row of 3) that is switched between the outer 2 pins.
     
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