Between Analog and Digital
From the Juno DCO to Samples and Back Again
In the 80's, oscillators in synthesizers evolved very quickly from voltage-controlled analog oscillators to purely digital oscillators as a part of an all digital signal chain. In between, there were only a few hybrid designs, combining digital clocks with analog waveform generators. We have found that there is a very exciting middle ground that went unexplored but remains relevant to this day
We start from a Juno-style digitally controlled oscillator built around a ramp generator and a reset circuit, discover that it can be generalized to generate many pitches at once, then realize that we've really built a crude multichannel independently variable sample rate DAC. This leads to an oscillator that is very simple in hardware, can generate a wide variety of waveforms aliasing-free, and most of all, is fun to explore new synthesis algorithms on.
Applications we've found this far include analog supersaws, wavetable-like analog waveforms, and even applying a FIR filter on an analog waveform, all while remaining aliasing-free.
Timo Alho
Lead Designer
Supercritical Synthesizers
A synth enthusiast since childhoold, I started writing my own soft synths in the 90's while in middle school, before plugins were a thing. Since then I became interested in analogue synths, taught myself some electronics, and strictly as a hobby started developing my own dream analog polysynth.
Fast forward a few years, my hobby has spiraled out of control and I'm now co-founder of Supercritical Synthesizers and the lead designer of the Redshift 6 synthesizer, which borrows many pieces from my hobby project, while implementing many new things more, and keeps evolving.