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Use Morley PVA as expression pedal


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Not so much a question, but a finding which might beneficial for others: the Morley PVA (optical volume pedal) can be used as an expression pedal for the Helix.

just connect the expression pedal jack to the output of the Morley using a normal TS-cable.Turn the minumum volume knob to the maximum position.

It looks as if  the Helix does an auto calibration (fw 2.53).


For me, the advantage that the Morley has over other expression and volume pedals, is that it uses an optical circuit instead of a potentiometer. So no mechanical wear. BTW: the 9V dc is used only for the the optical circuit, further signal path is passive just like standard expression pedals.

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Yes, the Morley is an all metal casing so it’s quite heavy.

I had it lying around and I saw some YT instructions on how to use potmeter-type volume pedals. So I thought this option should be possible too for the optical type. Did some measurements on how the resistance changes.

Now I only have to do the mod on the opening inside tge pedal to get a more linear path.

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