Midi behaviour of Pedals on GCP

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
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frama78
Posts: 2
Joined: Thu Jul 05, 2018 11:43 pm

Midi behaviour of Pedals on GCP

Post by frama78 » Thu Jul 05, 2018 11:44 pm

Hi there,

I have a GCP (V.2) and a Kemper. Now, I butchered a broken Cry Baby and converted it to an expression pedal with a toe-switch. Both connections are seperated. Pedal side jack on the left, switch side on the right.

Now, I have programmed Pedal 1&2 of the Ground Control and it actually works. P1 "normal" slider type 0...127 and P2 "switch" 0&127. So far, I´m really very satisfied but now comes the bummer:

When I put the Pedal to toe position, the value is 127. When I now activate the switch, the programmed P2-function jumps in BUT the value of P1 jums right to zero!!

I have no Idea, what´s the cause of this. I sifted the wires of the switch, because, I thought that maybe the polarity of it is worn, but no change in behaviour...


Can anybode give me a hint on what to do? how are the Mission-Pedals wired up?

JohnClark
Posts: 7079
Joined: Tue May 05, 2009 2:33 pm
Location: The Lab

Re: Midi behaviour of Pedals on GCP

Post by JohnClark » Fri Jul 06, 2018 11:32 am

Something is backward on your pedal would be my first guess, causing one port to influence the other.

Your switch should have the Tip connection switching between either the Ring or the Sleeve, so (most likely for a SPDT or DPDT switch) the Tip connected to the pin in the middle, the Ring and Sleeve connected to the pins on either side.

I don't know if you have the Dunlop "Hot Potz" or a more conventional type potentiometer type but your pot connections should have the Tip connected to the Wiper pin (or the one in the middle), the Ring connected to the CCW pin (or the one on the Left), and the Sleeve connected to the CW pin (or the one on the Right)

Post or email us (info@voodoolab.com) a picture of the guts of your pedal if you get stuck and we can try to sort it out for you.

I hope that helps!

frama78
Posts: 2
Joined: Thu Jul 05, 2018 11:43 pm

Re: Midi behaviour of Pedals on GCP

Post by frama78 » Sun Jul 15, 2018 4:35 am

oh... I´ve had the wrong type of switch and wired thwe pot wrong. That happens, when guitar players own a solderin iron and have a loosly idea of modding something... without the electronical knowledge of course.. :roll: :mrgreen:

Anyway: with your advice, I´ve got it done and it really rocks now! Maybe, I´ll look for a different tapered (linear?) pot because for a Wah, it´s great, but as conventional expression pedal, you have to be a little carfeful

Anyway: thank you so much! :)

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