Available as an assembled Module and as a DIY project.
This Module is discontinued.
Electrosmith 3340 VCO
The Electrosmith 3340 VCO is an all analog, voltage controlled waveform generator that uses a reissue of the legendary Curtis CEM3340 IC in the MU modular synthesizer format.
Many believe this chip to be the greatest sounding analog oscillator of all time. Simultaneous outputs of sine, triangle, sawtooth, and square waves are available. Temperature compensation circuitry provides precision volt per octave tracking over 10+ octaves across all temperatures and a configurable soft/hard sync input allows time reversal or hard reset of phase for each waveform. The square wave features PWM control with internal active clamp circuitry to limit duty cycle between 1% and 98%: your square will never go silent from PWM modulation. Linear and exponential FM inputs each offer input attenuverters for control over modulation amplitude as well. Snag a piece of history with the Electrosmith 3340 VCO.
https://www.electro-smith.com/modular/3340-vco-mu-assembled-full-diy-kit