Custom Hertz-per-Volt to Volt-per-Octave Interfaces
![Quad Anti-Log Converter Box](https://i0.wp.com/belltonesynthworks.com/blog/wp-content/uploads/2020/06/quad-box-2.jpg?fit=300%2C300&ssl=1)
![](https://i0.wp.com/belltonesynthworks.com/blog/wp-content/uploads/2020/06/alan-box-inside2.jpg?fit=300%2C300&ssl=1)
![antilog-installed-in-minikorg](https://i0.wp.com/belltonesynthworks.com/blog/wp-content/uploads/2020/06/antilog-in-minikorg.jpg?fit=300%2C300&ssl=1)
One of our clients commissioned us to build an interface that would allow him to control vintage synths with linear (Hertz/Volt) control voltage scaling such as Yamaha CS 10s, Yamaha CS-15s, Korg MS-10s and Korg MS-20s with conventionally scaled 1V/Octave equipment. We designed a custom PCB that contains two channels of anti-log conversion based on the Korg MS-02 and two channels of V-trig (positive-going trigger) to S-trig (ground-shorting trigger) conversion, and used two of them to create a 4-channel anti-log box in a racecar-striped enclosure with handmade cherry end cheeks. The box has its own built-in power supply. With it, our client is able to control 4 Hertz/Volt-scaled synth voices with the sequencers in his Eurorack system.
We have since adapted this same circuit to allow us to offer the service of adding built-in 1V/Octave control voltage inputs to any other Hertz/Volt synth, such as the Minikorg 700s as shown in the photo at right.
We can build a custom Hertz/Volt to Volt/Octave control voltage conversion box in any configuration you may wish!