Expression pedal switcher question – For Pitchfactor

[beedoola]

I built a little switcher box that was to serve to be able to switch which pedal my expression pedal goes to – Pitchfactor or Iron Ether Frantabit (bit crusher). I just used a standard 4dpt switch (extra poles were for LEDs) and wired the expression pedal to the middle set of lugs and 2 TRS jacks to the outer lugs – one outer lug was is the PF the other is the IE pedal.

Everything works but the problem is that when I switch from the expression pedal being used with the PF to the other pedal and then back to the PF, the max sweep of the expression pedal only reaches "88" on the display – not a full "100" as it should. So a whammy bend for instance won't reach the full octave reach.

Unplugging the expression jack from the PF and plugging it in again will reset it but this is a pain and not what I planned/hoped for. The purpose of the switcher was to be able to only need one expression pedal for two pedals.

Is there a way around this within the PF? Why does it do this?

[nickrose]

My guess is that it is the auto-calibration feature of the PF. Probably when the pedal is switched to the other thing, it appears an an open circuit to the PF, which is then viewed as 100%. As a result, when you switch back to the PF, the lower resistance of the actual pedal only gives you 88%. You could try setting up the switch so that when the PF is not selected, the tip is shorted to ground – this might fix the above problem.

[beedoola]

Excellent Nick! I'll try that. Thanks.

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