Prophet-600 © 1983 Sequential Circuits
The Sequential Circuits Prophet-600 was a six-voice analog polyphonic synthesizer designed as a more affordable alternative to the Prophet-5. It used two voltage-controlled oscillators per voice, a resonant low-pass filter, dual envelope generators, and a flexible modulation matrix. It is historically significant for being the first commercially available synthesizer to implement MIDI, marking a major milestone in electronic instrument communication.
The Prophet-600 provides 6-voice polyphony, with each voice featuring 2 VCOs, 1 VCF, 1 VCA, 2 ADSR envelopes, and 1 LFO.
It was designed as a lower-cost alternative to the Prophet-5, targeting competitors like Roland and Korg in the early 1980s synth market.
It is widely recognized as the first synthesizer to include MIDI (Musical Instrument Digital Interface) at launch, a breakthrough standard co-developed by Dave Smith.
Early units operated in MIDI Omni mode only, with later OS updates enabling full channel selection and improved control.
It includes a built-in real-time sequencer and arpeggiator, allowing simple performance recording without external equipment.
The modulation system (“Poly Mod”) allows cross-modulation between oscillators and filter, enabling complex FM-like textures in an analog context.
Its sound is often described as brighter and more aggressive than a Juno-60, with strong bass and brass character.
A known limitation of the original hardware is its relatively low control resolution and CPU-limited envelope response, giving it a slightly “steppy” feel compared to the Prophet-5.
Despite its quirks, it remains valued for its raw VCO tone and modulation flexibility, especially in bass and lead sounds.
Modern firmware upgrades (e.g., community mods) have significantly improved responsiveness and expanded its sonic capabilities.