Despite its lesser-known name, the 1982 Sequential Circuits Prophet 600 improves upon the Prophet 5 -- and goes at a much more affordable price point. As its name suggests, the Prophet 600 has a six-voice polyphony using 61 keys. It also boasts an onboard sequencer, an arpeggiator, and far more memory storage for patches, along with audio, MIDI, and CV I/O capabilities, giving it a flexibility that the Prophet 5 may lack.