Rossum Patent, “Circuit for DynamicControl of Phase Shift,” 3,969,682

Rossum Patent, “Circuit for DynamicControl of Phase Shift,” 3,969,682

Rossum Patent, “Circuit for DynamicControl of Phase Shift,” 3,969,682

ARP Patent, “Frequency Sensitive CircuitEmploying Variable Transconductance

Circuit,” 3,924,199

ARP Patent, “N-Pole Filter Circuit HavingCascaded Filter Sections,” 3,924,199

Polyfusion 4-Pole Lowpass Filter

Polyfusion 4-Pole Lowpass Filter

(image by Kevin Lightner)

Ray Wilson’s 4-Pole Lowpass Filter

can buy board at www.musicfromouterspace.com

SSM2040

http://www.synthmuseum.com/sequ/seqpro501a.jpgProphet 5, Rev 1

SSM2040 - 4-Pole Lowpass

http://www.synthmuseum.com/sequ/seqpro501a.jpgProphet 5, Rev 1

CEM3320

CEM3328

Crumar Bit 01

Ensoniq Mirage

René Schmitz’s SSM2040 4-pole lowpass clone

(see also Jürgen Haible and Ryan Williams)

René Schmitz’s SSM2040 4-pole lowpass clone

René Schmitz’s SSM2040 4-pole lowpass clone

Ryan William’s Analysis of the 2040 Core