Drum Oscillator trigger PW

[Harry Bissell]

Try building a peak detector. See National Semiconductor App notes AN-4, AN74
(a good choice for you, I think). You'll want the C1 value much smaller than
10uF (.01uf?). Use R2 to get the decay time you need. Twin Tees trigger very
well on short exponentially decaying pulses. Usuallu, you need to capacitivly
couple them into the twin-tee, and need to have the input pulse shorter than
one half cycle of the twin tee. If its longer it can disturb the ring or
trigger again on the reset of the capacitive coupled pulse.

I can help more next week, I be on vacation till monday. But by then you should
have about 500 good ways to do this. Good Luck  :^) Harry

Stewart Pye wrote:

> Hi,
>
> I'm building a velocity sensitive midi to Analog drum trigger circuit for
> my DR110 and other rhythm boxes. (They'll be separate units). I've already
> discovered that the oscillators respond well to varying amplitude triggers.
> Anyway, to save a little experimenting:
>
> How long does pulse have to be for the damping oscillators. They look like
> a twin tee based around a transistor. The reason I ask is because I am
> trying to avoid using Sample and hold. I'll drive the trigger ins from the
> MUX after the D/A. The clap pulses are 1ms 0V trigger . I'm using a
> software serial port for MIDI so it's going to be tricky (impossible)to
> have a delay longer than 20uS. Hopefully possible but a lot of juggling
> required. I guess if it needs a pulse wider than 20us I'll have to do
> something like the sample/hold in the paia Midi-CV with a software timer to
> reset the pulse to zero.
>
> Any Ideas anyone?
>
> Thanks,
>
> Stewart Pye