[sdiy] Demo of IM distortion in GX-1 VCF

[Paul Schreiber]

The diode filter in the GX-1 VCF (MOTM-485) exhibits severe IM (intermodulation)
distortion (around 22%!) at mid-to-high resonance settings. Here is a simple
sine wave sequence (MOTM-300 driven by MOTM-650 MIDI-CV prototype), with no VCA.
2 MOTM-485 VCFs in series (LP>>HP) do all the filtering/distortion. The LP
stage's resonance is modulated by the Velocity Out of the '650, and the CV MOD
depth (reversing attenuator) of the HP section is hand-tweaked as the sequence
plays.

Recorded in real-time (no dubs/edits): MOTM >>>Yamaha 02R/96 (with internal
delay)>>tc electronics M3000 reverb.

http:///www.synthtech.com/demo/485_sine.mp3

Paul S.