Moog Music Forum

Has anyone ever rebuilt the touch sensor bar on a Minitmoog? I have one I'm trying to repair, but the instructions in the service manual that I have don't seem to line up with what exists in my Minitmoog (it doesn't help that my manual is a copy so the pictures aren't the sharpest.) The construction of my touch sensor consists of an aluminum L bracket that mounts under the keyboard, with foam on top of the bottom of the bracket, than the nylon conductive material, which is attached to the ground shield of the sensor cable, then what I assume is insulating tape, then a round metal bar about 3/8 of an inch in diameter connected to the other wire of the sensor cable, and then some cotton batting. The manual discusses using a drain wire, is that supposed to be in place of the metal bar? Is the insulating tape supposed to be the dialetric between the nylon and the drain wire?

Any help would be appreciated, thanks!

Mark

Wow, I didn't even know that a Minitmoog had a sensor bar. I thought it was just a Satellite with more presets, learn something new everyday.

Not only does it have a touch sensor, but even better it has a second oscillator, which you can detune to thicken up the sound, tune to intervals like fifths, or sync to the other oscillator. So the sound is much better than the Satellite. I've owned a number of other preset analogs like the Pro Soloist, SY-2, and SH-2000, and while the presets on the Minitmoog aren't that good, the second oscillator makes it capable of better sounds than any of the others if you tweak the settings.


Mark

Answering my own question in case anyone else needs the information. I looked up the patent for the Minitmoog touch sensor, and figured out the operation for the original design. In the original, the surface of the cylindrical touch bar is non-conductive, the interior of the bar (which is connected to the sensor electronics) is conductive. When a key is pressed, the sensor bar is pressed down against the nylon conductive strip, and because of the foam underneath the nylon, the contact area between the nylon and the bar increases since the pressure causes the bar to press down the nylon into the foam, essentially wrapping the nylon around the bottom of the bar. The increased surface area equals increased capacitance, as the nylon is connected to the other conductor of the sensor electronics.


Mark