Odp: [sdiy] polivoks filter

[Roman Sowa]

I've seen this done unintentionally years ago. It was state
variable filter made by one of the list members. By simple
mistake it was working without caps, although caps were
included in the design, but not really used.
It sounded basically the same after I redone it to standard
SVF, but of course tuning range had to be shifted down.
I reckon capless filter works using buffer stray capacitance
and variable lag of OTAs dependent on Iabc.
I don't know what I'm talking here...

Roman

----- Original Message -----
From: Karl Dalen <karldalen at yahoo.se>
To: <uzs159 at uni-bonn.de>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, October 11, 2003 1:52 AM
Subject: Re: [sdiy] polivoks filter


> Exactly, listen here to what designer Vladimir Kuzmin
> says at http://www.muztech.ru/eng/history.php
>
> quoute; VCF doesn't have any capacitor at
>         all and use only two op amps.
>
> Now, that's interesting! I wonder how this is done!
> Another interesting thing is the VCA, it has
> differential outputs!
>
> KD
>
>  --- René_Schmitz <uzs159 at uni-bonn.de> skrev: > I wrote:
> > > The filter caps are not on the filter board, but on the connector
> > board.
> >
> > Oops, no they're not.
> >
> > --
> > uzs159 at uni-bonn.de
> > http://www.uni-bonn.de/~uzs159
>
>
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