> very interesting, thanks for the links.
>
> i cannot recall exactly from where i got the info, but
> i think that also the slide circuit is somewhat unique.
> a special ic was used for this, which is unavailable
> for many years now. but again i cannot recall what
> made it special, maybe a strange response curve.
> probably there are some ways to mimic that slide circuit,
> because it was not mentioned in the devilfish posting.
>
> best wishes
>
> ingo

Another special feature of the 303 was a dual potentiometer for the
resonance (i.e. two potentiometers with one common axis). The first
potentiometer was used to control the resonance, the second (simultaneously)
the envelope amount applied to the filter frequency (post the ACCENT
control). In addition this second potentiometer was not wired in the usual
way as an attenuator (with one terminal connected to GND) but kind of "AC
coupled GND": the terminal that is normally directly connected to GND was
connected via a 1uF capacitor to GND.

Best wishes
Dieter Doepfer