CEM3340

The CEM3340 is a self contained VCO, originally produced by Curtis Electromusic Specialties. With both exponential and linear control inputs and up to four output waveforms: triangle, sawtooth, square, and pulse with voltage controllable pulse width. It has full temperature compensation making it extremely stable. Also included is provision for hard and soft synchronization of the frequency, and an output for easy adjustment of high frequency tracking.

In 2016 after twenty or more years of diminishing availabilty, in response to Coolaudio's V3340 re-design of the part to the same specifications, OnChip Systems remanufactured the 3340.

Usage
The Digisound 80-2 and 80-3 are well designed and versatile analogue VCO and VCLFO. To prevent the IC being put under too much stress if/when the outputs are shorted, all outputs should have a series 1K resistor. The triangle wave output is unbuffered and should never be used to drive an output directly, add a J201 FET follower to buffer it. A better sine output can be achieved by using instead the Thomas Henry VCO-1 waveshaper.

Projects

 * A really good AS3340 VCO design!! by Eddy Bergman
 * Digisound 80-2 VCO, 1980
 * Digisound 80-3 VCLFO, 1980
 * VCO Deluxe by Thomas Henry, Polyphony, Nov/Dec 1981
 * Low-Frequency VCO Gives Exponential Response by Thomas Henry, Electronics, January 13, 1983, pp. 168-169.
 * Hyperflange + Chorus by Craig Anderton, Modern Recording & Music, Jul/Sep 1983
 * Build a Precision Controller Clock by Thomas Henry, Electronotes, May/June 1984, Special Issue E, pp. 11-17.
 * andrewF CEM3340 VCO, Mod Wiggler forum, Oct. 2016, for Eurorack
 * TimoRozendal &#x0005B;pcb+panel&#x0005D; CEM3340 VCO for eurorack (8hp), Mod Wiggler forum, Oct. 2016
 * Datasette OPECEM3340 – v3 (True Zero) on its way soon – Morph delayed, Mod Wiggler forum, Nov. 2016 and on Github, for Eurorack
 * The VCO Maximus by Thomas Henry, 2017
 * VCO CEM3340 PCB, Trilobite.audio
 * Kassutronics VCO 3340 (eurorack)
 * &#91;ORDER&#93; OCTOGINTA-II Digisound 80-2 eurorack version, Mod Wiggler forum, Feb 2018
 * Digisound in eurorack and &#091;ORDER&#093; Digisound eurorack, Mod Wiggler forum, Mar 2018
 * CEM3340 VCO Schematics and PCB!, Reddit/synthdiy, 28 Aug 2019
 * Dusk work Self-Tuning VCO