[sdiy] Compact VCF

[Harry Bissell Jr]

The Steiner-Parker filter (Ken Stone makes a CGS
clone)
would be a good choice... His design crushed the
circuit
onto a very small board.

I'd suggest the VCF1e design from Tom Gamble's EFM
(Electronics for Music) however I think all the
schematics may have been removed from the site (the
modules are discontinued so check for yourself).  
This design was based on the National Semiconductor
datasheet for the LM13600 / 13700 example of a lowpass
VCF.  

If you use a resonance pot instead of voltage
control...
this VCF could be done with a single LM13600 package
and maybe two transistors.

It would not track a keyboard CV as is, but otherwise
would satisfy all VCF functions nicely.

H^) harry



--- Karl Ekdahl <_nial_ at yahoo.com> wrote:
> Hi all.
> 
> I'm currently building on a portable synthesizer and
> i
> need a *small* VCF to fit in. Since i've got a zero
> budget (mark my words), i'd like something based
> around ordinary parts and possibly one or two
> CA3080's. I don't need anything fancy, just a
> regular
> lowpass with resonance and cutoff. The best
> alternative i've found so far is René Schmitz MS20
> clone, any other suggestions?
> 
> Thanks
> 
> Karl
> 
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