[sdiy] Pearl Syncussion VCO

[Harry Bissell]

Missing is the power supply pins for the 4069. I'd guess they are
V+ and V-

Think of the inverter in question as being an 'opamp' with the non-inverting
input at 'virtual' ground. You are looking at the inverting input and the output pin.
feedback is provided through the transistors.

Its a linear application of the CMOS inverter. Crappy opamp but dirt cheap, probably works
just fine.

H^) harry


----- Original Message -----
From: Ben Barwise <clackjunk at gmail.com>
To: synth-diy at dropmix.xs4all.nl
Sent: Tue, 04 Oct 2011 12:15:56 -0400 (EDT)
Subject: [sdiy] Pearl Syncussion VCO

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
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-- 
Harry Bissell & Nora Abdullah 4eva