303 clone filter and VCO

[Fraser, Colin J]

> -----Original Message-----
> From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
> Sent: 02 November 1998 14:09
> To: Fraser, Colin J; DIY
> Subject: AW: 303 clone filter and VCO
> 
> 
> 
> 	>The output of each pole in the Moog filter is 
> 'buffered' before it
> enters
> 	>the next pole.
> 	>Each stage has high input impedance and low output impedance.
> 
> Almost. In fact the buffer function is just the other way round:
> "Low" (well, actually frequency dependant) input impedance, 
> and high (current source) output impedance.
> 

Oops - must engage brain before typing.

What is the effect of this on the behaviour of the filter ?
It certainly sounds different, but is there just a difference in the slope,
an uneven slope, or some distortion, phase shifting or a.n. other effect
that makes the 303 filter sound the way it does ?

Has anyone done any simluation  / analysis of the 303 filter ?

Colin f