[sdiy] Booster for Synthacon VCF

[Michael Ruberto]

PLease omit R3 I forgot to take it out.

M. A. Ruberto


>From: "Michael Ruberto" <frankentron at hotmail.com>
>To: Brett.Maddaford at ipfx.com, synth-diy at dropmix.xs4all.nl
>Subject: RE: [sdiy] Booster for Synthacon VCF
>Date: Tue, 23 Aug 2005 22:03:53 -0400
>
>http://frankentron.freezope.org/source/Synthacon_VCF_REV3.gif
>
>I suppose this might help. My apologies for being such a tard, it's been a 
>very long day. But I just saved a bunch on my car insurance! yeah right...
>
>M. A. Ruberto
>
>
>>From: "Brett Maddaford" <Brett.Maddaford at ipfx.com>
>>To: "Michael Ruberto" <frankentron at hotmail.com>, 
>><synth-diy at dropmix.xs4all.nl>
>>Subject: RE: [sdiy] Booster for Synthacon VCF
>>Date: Wed, 24 Aug 2005 11:53:27 +1000
>>
>>Hi Michael
>>
>>Is this an original steiner filter or a CGS one? Any schematics etc on
>>what you did?
>>
>>
>>Thank
>>Brett
>>
>>-----Original Message-----
>>From: Michael Ruberto [mailto:frankentron at hotmail.com]
>>Sent: Wednesday, 24 August 2005 11:44 AM
>>To: synth-diy at dropmix.xs4all.nl
>>Subject: [sdiy] Booster for Synthacon VCF
>>
>>
>>Hi
>>
>>I was tinkering with the Synthacon VCF and added a simple FET amp to
>>boost
>>it's output. To my suprise I got something quite more than I
>>anticipated. It
>>does work properly - a 1Vpp signal in gives me a 2Vpp signal out with
>>the
>>resonance cranked and a 1Vpp at min res. However, I also get the
>>sweetest,
>>warmest, tube type sound I've heard lately. It's really quite delicious!
>>
>>On the O-Scope I see a rounding off of the linear portions of the
>>waveform.
>>With a sawtooth on the filter's input and cutoff completely open, the
>>waveform is a quarter circle shape. It seems I am overdriving the FET.
>>
>>Drawbacks, The VCF will not oscillate due to the loading down of it's
>>output
>>tranny. Might be worth it to add an op-amp buffer between the stages.
>>This
>>is basically a simple preamp and it can be used by itself or with any
>>other
>>module too.
>>
>>Give it a try, you won't believe your ears!
>>
>>M. A. Ruberto
>>
>>
>>
>
>