Roland TB-303

The Roland TB-303 Bass Line, a monophonic bass synthesizer and step sequencer released by Roland in 1981. It was meant to imitate an electric bass for guitarists practising alone, but it sounded unconvincing, sold poorly and was discontinued in 1984. Cheap second-hand units then found their way to electronic producers, who discovered that turning its filter cutoff, resonance and envelope knobs while a pattern played produced squelchy, squealing tones. Its “slide” (glide between notes) and “accent” functions added to the effect. That sound became the defining feature of acid house, starting with Phuture’s “Acid Tracks” (1987), and later of acid techno and acid trance. Original units are now highly collectable, and the 303 has been widely cloned in hardware and software.