TB-303 Voice

A faithful recreation of the Roland TB-303's acid-bass voice: a single oscillator through its unmistakable resonant ladder filter and VCA, with the snap of accent and the glide of slide. Mono and squelchy, built for basslines that bite. There's no built-in sequencer — you play it by gating the jacks, so drive it from any clock, sequencer, or keyboard.

How it works

A note fires when a gate hits Trig: the voice plays the pitch present at V/Oct and retriggers its filter and amp envelopes. Two more gates shape the performance. Hold Slide and the next note glides into pitch without restarting the envelopes — the classic 303 legato. Raise Acc alongside a trigger and that note comes through brighter, snappier, and louder. The resonant filter sweep, driven by the envelope and tightened by feedback saturation, is what gives the 303 its squelch.

Controls

• Cutoff — where the filter sits; the home base for every sweep.
• Resonance — emphasis at the cutoff; push it up for the screaming, vocal acid tone.
• Env Mod — how far the envelope sweeps the cutoff on each note.
• Decay — length of that sweep, from short blips to long falls (roughly 0.2 to 2 seconds).
• Accent — intensity of accented notes: more boost, brighter snap.
• Wave — pick the Saw or Square oscillator.

Inputs & outputs

• Trig — gate to play a note; each pulse retriggers the envelopes at the current pitch.
• V/Oct — 1V/octave pitch input.
• Cut — CV offset for the cutoff; ±5V shifts it ±2 octaves.
• Acc — gate it high alongside a trigger to accent that note.
• Slide — gate it high to glide from the previous note's pitch instead of jumping.
• Out — the voice output.

Tips

• For authentic acid lines, sequence Trig, V/Oct, Slide, and Acc together — slide and accent on just a few steps each is what makes a pattern sing.
• Crank Resonance and ride Cutoff and Env Mod by hand for the live knob-tweaking the 303 is famous for.