[sdiy] SSM2164 state-variable filter

[Ian Fritz]

At 08:27 AM 8/15/2008, Tom Wiltshire wrote:
>Hi all,
>
>I've done a bit more work towards trying to eliminate the frequency
>effect from the resonance on the SSM2164 SVF filter I'm playing with
>(http://www.sowa.synth.net/modular/m_vcf.gif). I'm just looking at a
>single filter section, without any of the CV mixer stuff.
>
>I drew a graph of the resonance response:
>
>         http://www.electricdruid.com/ResonanceGraph.gif
>
>Note the linear scale. It probably doesn't look as bad on a log scale!

Ah!  It wasn't clear before what you were talking about.  You problem looks 
to me more like a low frequency problem than a high frequency one.  Opamp 
phase shifts, slew rates, etc. aren't important at just a few 
kHz.  Something else is going on.

   Ian