SoundForce – DCO Digitially Controlled Oscillator based on Juno architecture
The SoundForce DCO is an oscillator for Eurorack based on the architecture of the Juno-60/106 oscillator section. It is a modern homage to that sound using technology from the future. It provides true analog waveforms with digital stability.
A DCO is not an all-analog VCO but also not a digital oscillator. It’s an hybrid design that combines the best of both. Similarly to many VCO’s, the DCO generates its core waveform, the saw wave, by charging a capacitor in an op-amp integrator configuration. A VCO will restart the waveform cycle when the signal has reached its maximum amplitude. But the DCO starts an new cycle when a micro-controller, a small computer chip, commands it to. The micro-controller also controls the rate at which the capacitor is charging, hence the frequency of the oscillator. As with a digital oscillator, the DCO acquires the CV input voltages and turns them into numbers that will later set the frequency of the oscillator. This is done inside the micro-controller using 16 bits sigma-delta analog to digital converters. All signals are true analog signals. The PULSE wave is derived from the SAW wave using a comparator and the SUB oscillators are generated using a flip-flop IC. Furthermore, the use of a very modern micro-controller with built-in 32 bits timers have improved the frequency accuracy a lot compared to the original design.
The SoundForce DCO features 10 slide pots (faders) reminiscent of the Roland synths. 5 sound sources are available: SAW, PULSE, SUB1 (1 octave lower), SUB2 (2 octaves lower) and NOISE. The built-in mixer allows you to mix them together using the faders and the MIX output jack. The PULSE has manual pulse width control, as well as PWM with a CV input and an attenuator. An FM input is also available with an attenuator. The oscillator can be hard synced to another oscillator using the SYNC input.