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Subject: RE: [chromapolaris] Pedal for the polaris

From: "Paul D. DeRocco" <pderocco@...>
Date: 2019-05-28

> From: karmakater@...
>
> Hit there, does anyone know which of the currently available
> pedals is best for the polaris? i have an M-Audio EX-P which
> has a rather small effective radius,
> any suggestions? thanks harald

From what I gather online, the EX-P has a 65K pot and a stereo TRS (tip-ring-sleeve) plug, where the tip-to-ring resistance goes from about 10K down to zero (heel to toe), and the tip-to-sleeve goes from about 55K to 65K. In other words, the pedal only moves the pot through a fraction of its range. There's no way to get this to work with the Polaris.

A Yamaha pedal has a 50K pot, and it uses the entire range of the pot. You could get this to work if you make an adapter to connect the ring contact from the pedal to the tip contact in the Polaris, and then tack a 200K resistor in parallel with R25 on the left panel board. This is because the Polaris expects a resistance between tip and sleeve that goes from zero in the heel position to 100K in the toe position. If you only give it 50K, the voltage will only swing about half as far, so you need to cut the pull-up resistor in half, too.

You could do something similar with a Roland EV-5, but it's 10K, so you'd need around a 22K resistor, and you have that awful pot on the side of the pedal that prevents it from going all the way to zero if you don't remember to turn it fully CCW when you set it up.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...