VCO 3340

A basic but complete application of the 3340 VCO

The CEM3340 VCO chip is one of the legendary chips designed by Doug Curtis that played an important role in the analog polysynths of the 1980s. By integrating a complete analog VCO on a chip, it made more compact and cost-effective synth designs possible.

Together with the classic analog polysynths themselves, the Curtis chips have long been out of production. In 2018 however, thanks to the new boom in analog synthesis, the 3340 VCO chip is once again available, from no less than three sources. Curtis' own company OnChip Systems re-issued the CEM3340 Rev. G, and cloned/compatible devices are available from CoolAudio (v3340) and from the Latvian company Alfa (AS3340).

This module is designed to be a basic but complete application of the 3340 VCO for Eurorack modular synthesizers. It provides the three standard waveforms output by the 3340, buffered and scaled to standard modular levels, as well as a sine wave output. It further exposes the FM and Sync features of the chip to the user.

The 3340 chip is known for good tracking and temperature stability, making the build of a robust VCO uncomplicated and affordable. Further, this module uses onboard voltage regulators to reduce sensitivity to power supply fluctuations and limit self-heating of the VCO chip.

Copyright Caspar Ockeloen-Korppi 2018

https://kassu2000.blogspot.com/2018/06/vco-3340.html