The filter topology of the 517S is based on circuits known from Oberheim’s Xpander and OB-XA. The module comes equipped with potentiometers for the cutoff frequency and resonance. Via a switch, users can choose between high-pass (-18 dB per octave) and low-pass characteristic (-24 dB per octave). There are two CV inputs for cutoff modulations. One of them features a bipolar attenuator. The resonance is equipped with one control voltage input.
Audio input and output
Two cutoff CV inputs
Resonance CV input
5U module in Moog form factor, one unit wide