The core of the VCO is borrowed from the famous Russian synth Polivoks VCO and in exponential converter we use the original matched transistor IC that was used in Polivoks.
We have significantly updated schematics:
- Introduced +-10V regulators for greater stability of operation,
- Adjusted signal amplitudes to match requirements of contemporary modular synths and made all output signals available simultaneously,
- Redesigned CV inputs to accept positive CV signals,
- Introduced PWM circuit with manual and voltage controlled pulse width,
- Introduced synchronization input, so you can sync the VCO to other VCOs.
This is a comparably complex DIY project for experienced builders. We do not recommend this for beginners and ones without proper soldering and testing equipment.