SSM2040

The SSM2040 is a four pole VCF IC with the cutoff frequency exponentially voltage controlable. Designed by Dave Rossum of E-MU Systems and used in the first 2 versions of the Sequential Circuits Prophet 5. "This SSM 2040 VCF is widely acknowledged as one of the best filter chips ever put in an analog synthesizer." Early SSM chips were often defective, and having to pay royalties led Sequential to switch to Curtis ICs in later versions of the Prophet 5.

Synthesizers using SSM2040 ICs

 * Digisound 80-7
 * RSF Kobol Expander I
 * Sequential Circuits Prophet 5 Rev 1 & 2
 * SRM Synthesizer Octave Cat
 * Steiner EVI
 * Thomas Henry: A four-pole lowpass VCF - SSM2040

Clones

 * Division 6 Filtare SEIII
 * HM2040
 * Jürgen Haible SSM2040 filter
 * Synthesis Technology MOTM-440
 * Tiptop Audio Z2040

Data sheets

 * MaxMidi Rare Silicon
 * CEM3374.com