[sdiy] discrete/no-OTA VCO

[David G. Dixon]

Dave,

Check out Ray Wilson's site, Music From Outer Space.  Here's a link to a
simple VCLFO using only opamps and transistors:

http://www.musicfromouterspace.com/analogsynth/lfo.html

It's basically a simple ramp oscillator with some simple wave shaping
circuitry.  There's one OTA there, but only for sine shaping, which you
don't want.

David G. Dixon
Professor
Department of Materials Engineering
University of British Columbia
309-6350 Stores Road
Vancouver, B.C.  V6T 1Z4
Canada
 
Tel 1-604-822-3679
Fax 1-604-822-3619
 
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-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of DAF
Sent: Sunday, December 28, 2008 1:52 PM
To: sdiy
Subject: [sdiy] discrete/no-OTA VCO

Hello - can someone point me to a circuit for a  voltage-controlled lfo that

uses discrete or other easy to source parts.  I have used an OTA-based 
design in the past, but I want to design around more generic parts.  I seem 
to remember a vco that used a discrete JFET?  I don't neet expo response or 
temp compensation.  I am looking for about a 2 to 10 Hz response range.  I 
don't want to use any specialty chips or OTA's, just discrete transistors 
and op-amps.   Any help greatly appreciated.

thanks,
Dave 

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