SSM2040
The SSM2040 is a 4-pole VCF IC from SSM with the cutoff frequency exponentially voltage controlable.[1] 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.[2][3]
Clones and schematics
In chronological order:
- discrete SSM2040-style filter by Jürgen Haible, 1997.
- SSM2040 Style 4 pole Filter by Jürgen Haible, 1998. A discrete version that reproduces the original sound. A lot of component selection is needed (matching transistor pairs). The circuit is not a pin for pin replacement, and it has a voltage controlled resonance path added. There'a little error in the drawing: the pnp current mirrors have C and E mixed up.
- SMD SSM 2040 filter by René Schmitz, 1999
- 4-pole VCF by Osamu Hoshuyama, 2002
- The SSM 2040 Integrated Circuit, by James Gideon, 2006
- SSM 2040 style VCF + discrete VCA (AMORE), 2011. Both circuits by René Schmitz.
- Discrete Transistor 2040 SVVCF by Scott Stites, electro-music.com forum, Apr. 2013
Synthesizers etc. using the SSM2040 or clone
- Digisound 80-7
- Division 6 Filtare SEIII
- Hearn Morley HM2040 potted module.
- Mad Science Lab SSM2
- Mattson Mini Modular FV1-B, based on the SSM2040 designed by Jim Patchell
- Radio Junk Box 2040 VCF
- RSF Kobol Expander I
- Sequential Circuits Prophet 5 Rev. 1 & 2
- SMB-1 Project
- SRM Synthesizer Octave Cat
- SSM2040 VCF by Ryan Williams, March 2007.
- Steiner EVI
- Synthesis Technology MOTM-440
- Tiptop Audio Z2040
- VCF/Phase Shifter by Craig Anderton, AMS-100 guitar processor, Device 6, 1979
- Vedic Scapes Model 2040, uses the HM2040
- Voltage Controlled Phase Shifter module by Craig Anderton, AMS-100 guitar processor, Device 4, 1979
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See also
References
- ^ SSM2040 data sheet
- ^ SSM 2040 Voltage Controlled Filter Chip History, Mad Science Lab 2008
- ^ SSM 2040 VCF with LFO, Mad Science Lab 2008
Further reading
- Circuit for dynamic control of phase shift, US Patent US3969682, by David Rossum, 1974
- SSM 2040 data sheet at MaxMidi Rare Silicon or CEM3374.com
- Build a better music synthesiser by Thomas Henry, Tab Books Inc, 1987, ISBN 0830627533, Chapter 6: A four-pole lowpass VCF - SSM2040
- Electronic Music Circuits by Barry Klein, Howard Sams, 1982,ISBN 0-672-21833-X, pages 125-126, 135-137, 141
- Two ICs For Electronic Music - SSM2020 And SSM2040 by Dave Rossum, Electronotes 78, Volume 9, 1977, p. 15
- Reader's Circuits - VCF With SSM2040 by Rich Ryan, Electronotes 84, Volume 9, 1977, p. 17
- Additional Design Ideas For Voltage-Controlled Filters by Bernie Hutchins, Electronotes 85, Volume 10, 1978, p. 5
- A Fourth Order State-Variable Filter by Bob Chidlaw, Electronotes 99, Volume 11, 1979, p. 3
- Musical Applications of Microprocessors by Hal Chamberlin, Hayden, 1985 ISBN 0-8104-5768-7, pages 218-220, 599, 603
External links
- SSM2040 VCF by Ryan Williams, March 2007.
- SSM 2040 style VCF + discrete VCA (AMORE), 2011. Both circuits by René Schmitz.