[sdiy] Pearl Syncussion VCO

[Ben Barwise]

Hey,

I have been exploring lots of drum synthesizer schematics and I am
currently looking at the Pearl syncussion. I was wondering if someone
could give me a few tips on certain parts I am finding confusing in
the VCO.


I understand the integrator and schmitt trigger and then sort of get
the CV input but I am just completely lost what is happening with that
inverter stuck on the side of that PNP pair at the top - is that just
a good way to tie up unused pins? does this schematic seem a bit
bonkers? because I have traced it from that well known scan hanging
around the internet (why do people bother scanning schematics you cant
read! ) the inverters are guessed as 4069's they may not be.

it is an interesting design anyway,

http://img88.imageshack.us/img88/1884/pearlsyncussionvco.jpg