MOTM

Hey Chad!

I built a dual version of a trigger generator designed by Mark Media 
et al., from Stooge Larry's website - 
http://www.wiseguysynth.com/larry/users/mark1/trigger.htm -and it 
works very well.

This circuit uses a DV/DT comparator followed by a one shot timer.  
Any change in voltage amplitude over a change in time (delta 
voltage/delta time) makes the comparator output go high.  The 
comparator is actually producing a negative going trigger to fire the 
555 timer in one shot mode.  The output is a short, positive going 
pulse which works nicely with any trigger input.

What's great about this circuit is that it will work with ANY 
waveform at the input.  Sine, triangle, square or totally wack 
complex and high or low frequency - it doesn't matter!  I use it to 
send triggers to my EG's in place of an envelope follower, creating 
separate notes from otherwise continous modulated signals.  For 
example, modulate the pitch of an oscillator with a sample and hold 
and send the oscillator output to the trigger generator.  Send the 
oscillator throughput to a filter and the trigger out to the EG which 
modulates the filter.  Every time the sample and hold changes the 
oscillator pitch, the EG/filter shapes the note timbre.

Simple and effective, but it may not be "tight" enough for guitar.  
Much will depend on the attack of the instrument.  I'll plug a 
guitar/preamp combination into it and let you know what happens.  I 
can assure you, though, it works very well in any synth application 
I've been able to dream up!

Chub

ps- I've got the pcb layout for my dual version around here 
somewhere... 

--- In motm@yahoogroups.com, "chad_kettering" <chad_kettering@y...> 
wrote:
> 
> Hello,
> 
> I am building a MOTM system for not only analogue synthesis but also
> to process other synths and acoustic sources. The Synthesizers.com
> module looks like a great idea to generate a gate signal from an 
audio
> source to control an EG for a MOTM filter. Is it effective?
> 
> Or should I use a Midi signal to trigger a gate generated by a Midi 
to
> CV converter?
> 
> The midi triggering concerns me a little due to possible latency 
issues. 
> 
> Thanks