DJW Audio Introduces DW-303, a Free Open-Source TB-303-Style Synthesizer
DW-303 is a free, open-source TB-303-style bass synthesizer featuring circuit-modeled sound generation, a 16-step sequencer, 64 patterns and support for multiple plugin formats and operating systems.
UK-based DJW Audio has released DW-303, a free, open-source bass synthesizer and step sequencer modeled on the classic Roland TB-303.
The software recreates the original instrument’s oscillator, filter, envelope and amplifier circuitry through component-level modeling, with versions available for macOS, Windows and Linux.
Rather than using a conventional virtual-analog synthesis architecture, DW-303 models the TB-303 signal path stage by stage using the original circuit schematic. The developer says the models were subsequently fitted against measurements of hardware, including the behavior of the filter resonance, accent and slide circuits.
The synthesizer includes sawtooth and square waveforms, a resonant ladder filter and controls for cutoff frequency, resonance, envelope modulation, decay and accent. A Full quality mode performs the complete circuit simulation, while an Economy mode offers a lighter processing option.
DW-303 also recreates the TB-303’s characteristic 16-step programming workflow. Notes are entered in pitch mode, followed by rhythmic programming in time mode, with individual steps supporting notes, ties, rests, accents, slides and transposition.
Features:
- Stage-by-stage circuit modeling of the oscillator, ladder filter, envelopes and VCA.
- Sawtooth and square oscillator waveforms.
- Resonant ladder filter with adjustable cutoff and resonance.
- Filter envelope with adjustable envelope modulation and decay.
- Accent circuitry with interaction between resonance and filter modulation.
- 16-step sequencer with separate pitch and time programming modes.
- 64 patterns organized into four groups, each with A and B sections.
- Seven tracks for chaining patterns into longer arrangements.
- Per-step accent, slide and transpose controls.
- Internal, MIDI clock and DAW host synchronization.
- MIDI keyboard input with last-note priority, portamento-style slides and velocity-controlled accent.
- Full and Economy circuit simulation quality modes.
- Factory patterns included.
DW-303 supports VST3, AU, AAX, CLAP and LV2 plugin formats, depending on operating system, as well as standalone operation. When synchronized to a DAW host, its sequencer follows the host tempo and transport, with patterns saved as part of the project session.
DJW Audio DW-303 is available free of charge for macOS 11 or later, Windows 10/11 and Linux x86_64. No license key or activation is required. The source code is available under the GPL-3.0-or-later license. Visit the official DW-303 product page for downloads and installation information, or visit the GitHub repository for the source code.
