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Re: EDP Feedback pedals...

At 8:29 PM -0700 5/21/98, future perfect wrote:
>Kim said....
>>there's no way to set the feedback range in the echoplex, but its a 
>thing to
>>do by using different types of potentiometers or putting resistors in
>>series with the potentiometer.
>Forgive my lack of electronics knowledge, but there is a 100k pot in my

A 100k pot will compress the useful range of the pedal into a smaller area,
which will make it a bit harder to use. As soon as the wiper of the pot is
anywhere past about 18k, you will be at the full feedback level. If you
change the pot to 20k linear, you will find it to be much easier to

>pedal...between what 2 lugs on the pot do I wire a resistor, and what 
>should the resistor be to get it closer to the recommended 20k range?

Putting a resistor in series with the pot would mean that the pedal would
not sweep the resistance all the way from the minimum to the maximum. You
basically stop it from going all the way on one side or the other. So
either you couldn't go all the way to maximum feedback, or you couldn't set
feedback all the way to zero. This would also mean that the pedal sweeps
you through a more limited range of feedback values and might make it
easier to control. This is similar to what Fred suggested of sticking a wad
of tape under the pedal as a stopper. It's just doing it electronically
instead of mechanically.

If the resistor is between the "tip" of the jack and the wiper pin of the
pot, you would not be able to get to max feedback. This is probably not
what you want, but would give the pedal control over a more limited range
of lower feedback values.

If the resistor is between the ground of the jack and the end pin of the
pot, you would not be able to get to minimum feedback. This would limit the
pedal to controlling upper feedback values.

The value of resistor would be up to you, as that would set the range.

Probably any decent midi controller pedal could be programmed to do this
same thing, no need for soldering irons.


Kim Flint                   | Looper's Delight
kflint@annihilist.com       | http://www.annihilist.com/loop/loop.html
http://www.annihilist.com/  | Loopers-Delight-request@annihilist.com