Wiardgroup

For the technically inclined, have a look at

http://www.musicsynthesizer.com/Circuitry/Multi-Function%20VC
F.htm

The opening block diagram is practically a schematic for the 
Boogie filter with A,B,C and D being the 6,12,18 and 24 dB per 
octave outputs. The mixing is done externally by YOU. The 
resistors shown are actual Vactrol resistors in the Boogie 
design, instead of a shorthand symbol for the OTA's in a 3372 
chip.

That eliminate about 100 transistors from the signal path, and 
should be much quieter. Plus the mixer can be VCA based like 
the Blacet Quad VCA. So a sequencer or 4 envelopes can be 
used to mix the filter "poles" for filter mode sequencing or 
envelope morphing.

The link wrapped, damn. I added the link to the "Links" section at 
the left of page. Also switch S1 is not needed since it is replaced 
by a patchcord. Ha, Ha



--- In wiardgroup@yahoogroups.com, "grantrichter2001" 
<grichter@a...> wrote:
> 
> For the technically inclined, have a look at
> 
> 
http://www.musicsynthesizer.com/Circuitry/Multi-Function%20VC

> F.htm
> 
> The opening block diagram is practically a schematic for the 
> Boogie filter with A,B,C and D being the 6,12,18 and 24 dB per 
> octave outputs. The mixing is done externally by YOU. The 
> resistors shown are actual Vactrol resistors in the Boogie 
> design, instead of a shorthand symbol for the OTA's in a 3372 
> chip.
> 
> That eliminate about 100 transistors from the signal path, and 
> should be much quieter. Plus the mixer can be VCA based like 
> the Blacet Quad VCA. So a sequencer or 4 envelopes can be 
> used to mix the filter "poles" for filter mode sequencing or 
> envelope morphing.