From Ken Stone’s CGS website:
This VCO started out life as a replacement for the original VCOs in my ’73 Serge, so it replicates a lot of the functionality of that module. Of course there have been numerous enhancements to the design as well, making it right at home in a 1 volt per octave synthesizer. The core chosen is the well known Electronotes ENS-76 VCO Option 1 as used in the ASM-1, Modulus, etc. This core was an obvious choice due to the amount of information, lists of suitable substitutes and so on that are available on the web.
- Custom 1U Front-Panel-Express panel
- Sawtooth wave output is +/-5V
- Pulse wave output comparator DC coupled to sawtooth
- High quality parts throughout
- Some resistor value changes
Check out the CGS VCO Project page.