Minimoog Vcf

[Sean Costello]

Martin Czech wrote:
> 
> > Hi:
> >
> > The schematic in question is one that I scanned in.  There were some
> > components in error on the original schematic (as compared to other
> > schematics) which I corrected; I may have typed in a value that is
> > incorrect.  I'll look at my other Minimoog VCF schematics, and see where
> > the problem might lie.  I'll keep the list posted.
> >
> > Sean Costello
> >
> 
> Did I miss the final answer?  It would be very interesting to know, why
> the famous circuit won't work after above mentioned schematic. Cause
> I'm going to build one in the next time.

I have just looked at the 3 schematics I have - the one scanned in from
the Minimoog service manual, the drawing of the filter alone from an
earlier version of the manual, and a hand-drawn version by Gene Stopp. 
All of them have the positive power supply connected to the collector of
Q6 (in the output differential amplifier).  Two of them show R20 and R24
to be equal in value (220K); as the version I scanned in had a different
value for R20, I assumed it was a typo, and changed it to be equal to
R24.  I haven't found any other errors in the schematic I posted.  This
is in no way saying that the schematic is accurate, just that it
corresponds with the other Minimoog filter schematics that I have.

Sean Costello