Blinkenlights 3340 VCO

Slim, skiff friendly bare bones VCO, compatible with 3340 chips

A high quality analogue VCO, with a pared-down circuit design comprised entirely of through-hole components.

• 4HP wide
• 4cm deep including the power plug (skiff friendly)
• Supplied with AS3340 chip
• Scale and High Frequency trimpots are accessible through the front panel, so you can tune the VCO while it's installed in your rack
• Square, Ramp and Triangle wave outputs
• Pulse Width control voltage input with attenuation control, plus Pulse Width knob
• All through hole components
• Bare - bones simple design

This module is designed around the amazing 3340 VCO chip. Its thin profile and shallow depth makes it perfect for a small performance rack, or a setup with multiple VCO modules. The module is compatible with the AS3340, CEM3340, or any clone chip with the same functionality and pin assignment.

3340 chips output each waveform at different amplitudes, and to reduce component count (decreasing size, and making the module quicker to assemble) this module does not level shift the waveforms to match one another. In my own experience, this doesn't make much difference to the functionality, because most patches will either only use one waveform from each VCO, or mix them together at customised levels via other modules. The module buffers all the outputs, because otherwise the 3340 chip will not work correctly.

The waveform output levels are:
ramp wave 0 - 8V
triangle wave 0 - 4V
square wave 0 - 10.7V

https://www.tindie.com/products/nbirch/3340-vco-kit-eurorack-module-4hp/