More neat questions...

Soundwave [Chad Gould] cgould at
Thu Mar 5 23:52:49 CET 1998

Alright... I think I worked out some of the wrong junk that was in the
previous schematic... I just have some more questions (but of course!)

1) How much current is required for an instrument to detect a CV, in
general? The current setup I'm going for uses (in general) a fixed
resistor of 10K and a variable resistor of 1M - meaning the current is
at max 1mA (with the current varying according to what the variable
resistor is) - is that enough? The current can easily be changed by
playing with the fixed resistor value.

2) Also, should the 1M pots be audio or linear? 

3) I'm planning on doing this project fairly free-form (no board
prototyping) since the only non-panel mounted parts are resistors.
However, I can see one problem with the project: ground. For every LED
in the circuit, I got to run it with a resistor (440 ohms) in series and
move directly to the ground terminal. My question: is
an earth-based ground going to provide the same effects as the battery
ground? It'd save an awful lot of wiring. (: 

4) Lastly, one of my LEDs looks like it's going to have variable
amperage. This is the snipplet (without all the extra detail:)

+10.5V------/\/\/\------------|---------------/\/\/\-------|> gnd
            ribbon     |      |                10K
            (0-1M)     |      ---- CV Out 
                       -----------|>------/\/\/\---------|> gnd
                                 LED       440 ohm

This I think produces 0-20mA in the LED circuit. (Right? Let me know. (:
) So if there are any sort of things that act cool with variable
voltages besides LEDs... (:  (A standard LED would simply dim and go off
when the ribbon is pressed, I think.)

Chad Gould aka Soundwave                 |studio: 7 real synths
internet: cgould at                |and a cheap Casio
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