An iconic synthesizer,
modeled down to the last circuit.
A legendary sound
The Pro-One is one of the most iconic monophonic synthesizers ever built. Designed by Dave Smith in 1981, it defined the sound of an era with its aggressive oscillators, screaming filter and intuitive modulation matrix.
Coded from the original schematics and service manual, The-One models every stage of the signal path with its imperfections, the very ones that give the Pro-One its character. It's not a reproduction, it's a study that sounds.
CEM 3340 oscillators with MinBLEP antialiasing (8 zero crossings, Blackman-Harris window) and hard sync
CEM 3320 OTA filter with g-dependent thermal voltage scaling, self-oscillation, and soft Nyquist ceiling
CEM 3310 ADSR envelopes with RC overshoot target (1.3×) and circuit-calibrated timing curves
Full modulation matrix with circuit-derived bus gains and resistor-ratio depth calibration
40-step sequencer, arpeggiator with beat-locked DAW sync (22 subdivisions), and sidechain audio input
Koren 12AX7 tube saturation (3 interpolated lookup tables) and Revox B77 tape model with head bump and HF roll-off
Key Features
Raw oscillator character
Two CEM 3340 oscillators with saw, pulse, and triangle waveforms. Variable pulse width, hard sync, and a dedicated LFO give you the full palette of Pro-One timbres, from fat basses to screaming leads and evolving textures.
The filter that defines the sound
The CEM 3320 4-pole low-pass filter is the heart of the Pro-One. Our OTA-based model captures its unique saturation, the screaming self-oscillation, and the musical keyboard tracking that lets you play the filter chromatically.
Deep modulation, instant results
Three sources, five destinations, two independent buses. The modulation matrix faithfully reproduces every routing of the original, with circuit-accurate gain staging. Add the tube and tape saturation for extra warmth and grit.
Specifications
- Circuit-level emulation of the Sequential Circuits Pro-One (Model 100, 1981)
- 2 MinBLEP oscillators (CEM 3340) with saw, pulse, triangle, hard sync
- 4-pole 24dB/oct OTA filter (CEM 3320) with self-oscillation
- 2 ADSR envelopes (CEM 3310) with true exponential curves
- CA3280 OTA VCA with circuit-accurate transfer curve
- Full modulation matrix: 3 sources, 5 destinations, Wheel/Direct buses
- LFO with saw, triangle, square waveforms and gate sync
- 40-step sequencer (2 banks) with real-time transposition
- Arpeggiator (UP / UP-DOWN) with DAW tempo sync
- Koren 12AX7 tube and Revox B77 tape saturation extra
- Mono/stereo algorithmic reverb extra
- 20 factory presets from the original Owner's Manual
- MIDI Learn on all knobs, sidechain audio input
- VST3 & AU · macOS & Windows
System Requirements
macOS
- macOS 11.0 (Big Sur) or later
- Intel or Apple Silicon (Universal Binary)
- VST3 / AU
- 4 GB RAM minimum
- Any VST3 or AU compatible DAW (Logic, Ableton, Reaper, Bitwig…)
Windows
- Windows 10 or later
- x64 processor
- VST3
- 4 GB RAM minimum
- Any VST3 compatible DAW (Ableton, FL Studio, Reaper, Bitwig, Cubase…)