Modular Synth Panels

I just finished building (and them significantly modifying) my CGS
drum simulators. I built a 3 tone model behind a 1U Stooge panel.

I have been looking at the panels here in the group and wonder if
anyone has actually ever built one on these panel designs. I say
this because the two I see bring out the RES control which is
normally a trimmer on the board. My expereince is that this control
has only a very small sweet spot and a front panel control would be
touchy to useless unless one used a small pot in series with a
resistor on each side once the known point was found.

Also, I did not see a panel where anyone is attempting the "tune"
modification. After implementing this, I have a whole new concept of
how I would build my next CGS drum simulator package.

And finally, on my drum simulators the Lumex LEDs would hardly light
up at all. I installed a modification that consists of one resistor
and one common NPN transistor (about any will do) that fires the LED.

Since I see drum sim panels, I woudl be interested in hearing from
others than have built theirs.

Larry Hendry

--- In motmpanels@yahoogroups.com, "Larry Hendry" <hendrysr@y...>
wrote:

> I have been looking at the panels here in the group and wonder if
> anyone has actually ever built one on these panel designs. I say
> this because the two I see bring out the RES control which is
> normally a trimmer on the board. My expereince is that this

control

> has only a very small sweet spot and a front panel control would be
> touchy to useless unless one used a small pot in series with a
> resistor on each side once the known point was found.
>

This is similar to what Ken recommends in his instructions:
#

Do NOT bring the resonance trimmers out to the front panels as
controls. They are very much a "set and forget" adjustment.

That being said, if you still want to bring them to the panel, first
set the trimpot on the board to find out where the resonance point
occurs. Measure the resistance of the two sides of the trimpot from
the wiper. Remove the trimpot from the PCB. Pick two trimpots that
have sufficient range to cover these values. Pick a pot with a small
resistance value, say 1k to 5k, and solder it between the two
trimpots, with the wiper going to where the wiper of the original
trimpot went on the PCB. Wire the other ends of the trimpots to the
remaining trimpot connections on the PCB, the result being that you
have two trimpots in series with the panel mounted pot. It should now
be possible to adjust the trimpots so that range of the panel mounted
pot goes from the shortest possible output, to just before the
oscillator starts free running.