Rick's Moog VCF Clone question

Rick Jansen sscprick at horus.sara.nl
Tue Sep 12 09:49:05 CEST 1995

In message <Pine.OSF.3.91.950910122414.16862A-100000 at gonzo.wolfe.net> you wri
> I want to build Rick's adaptation of the Moog ladder vcf.  I don't really 
> care about the temperature stabilization part of the circuit, so I'm 
> wondering if I could just replace the LM329 diode with a regular diode or 
> a resistor.  I suppose I could just leave out the temp. control part 
> altogether.  IT's not absolutely essential that the Exp. Geneerator 
> transistors be matched, is it?  Doesn't seem to be an issue with the EMS 
> vcf clone.

You can simply leave out the temperature control circuitry. 
It's just luxury and not really necessary for a VCF. The LM329
cannot be replaced by just a diode. To not use the temperature
control leave out R1-R9, D1, D2, C1. Ground the inputs of A1,
just to be sure.

The cost of the temperature control isn't high though, the LM329
being the main part.

The original Moog VCF schematics do tell you to match discrete
transistors within certain limits. But, why not use the (cheap)
LM/CA 3046? They're really cheap and multi-sourced ic's.

I have made a PCB which I could order for people interested.
Cost: ca US$ 25,-

Rick Jansen
rick at sara.nl   http://www.sara.nl/Rick.Jansen
S&H's a module and s&h's looking good

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