Cgs synth

On 7/3/08, Jeff Foster put forth:

>I found the triggers via an LED with 2k res. to ground. pooked the
>positive leg on the pcb traces until it lite or flashed. The
>brightness was pretty good.

That leads me to believe that it is more than 5V, but I would
double-check your resistor value.

Do you have a DMM?? Most have sample and hold.

>When the led was on the triggers for the
>hi hat, the sound of the hi hat changed, closed hh and conga were
>not affected. I think they are positive pulses? An OR gate would be
>right.

If it's effecting the sound, then I would guess that it drawing too
much current. Although I would guess 2K would be a high enough
impedance. Perhaps you should poke around a bit more.

>maybe a simple PNP tranisotr? next is to get the pulses up to at
>least +5v, right?

I'm not much of a discrete transistor guy, but I think an emitter
follower would use an NPN?? Anyway, if a 2K LED resistor was drawing
too much current, you might have trouble saturating the base. Imho,
bipolar transistors are rather low impedance devices that burn out
almost instantly with too much current, making them a PITA,
especially when dealing with unknown values. Otoh, if you have the
room, a single-sided op-amp like an LM358 is pretty bullet-proof.

On 7/2/08, Jason Proctor put forth:

>you could perhaps use the gate converter module. 4 comparators on a
>little PCB. tweak the comparison point down a bit perchance.
>
>http://cgs.synth.net/modules/cgs56_gatecon.html
>

He mentioned he wanted single-sided (although I guess he could use a
different amp).