Archive of the former Yahoo!Groups mailing list: MOTM

I'm often designing CV inputs to work with a passive pedal.
First application for CV inputs is a ∗voltage∗ of course,
0 ... 5V or +/-5V from other modules.
Then further, these CV inputs are often normalized. That is,
if no plug is inserted, a positive voltage is applied internally
over a resistor. Therefore the CV attenuator can be used
as additional manual control.
Third - and now we come to pedals - if something with a higher
impedance is plugged into some CV inputs - i.e. not a voltage source,
but a variable resistance - this external component will form a variable
resistor divider with the internal bias (normalizing) resistor.
So a wide variety of external sensors can be plugged in directly
into the CV input. Passive Pedals (normal Volume pedals, using
the output connection only), Photo resistors, simple ribbon controllers
- you name it. Anything that forms a variable resistance that is in the
right range.
As for that, the right range, you have to experiment a little. Keep
in mind that this is a bonus feature, so depending on the resistance
of the volume pedal (and depending on the specific module) you
will get a better or smaller control range. I can't tell you offhand
what the best value is (it also depends on the pedal being linear
or audio taper) - I just encourage you to experiment, try different
things, and come back with your results.

JH. (speaking not of all MOTM modules in general, not even of
all that are my designs - I put in in where I thought it fitted
and where the constraints of the circuit would allow.)