[sdiy] Pearl Syncussion VCO

[Magnus Danielson]

On 04/10/11 18:15, Ben Barwise wrote:
> 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

It's a bias voltage source... "buffered" if you so like.

Cheers,
Magnus