Korg Mono/Poly MP-4 Analog Synthesizer

The instrument

The Korg Mono/Poly and the Korg PolySix came onto the market at the same time in 1982. They are similar in design, but are based on very different concepts. The Polysix is a fairly simple 6-voice polyphonic single VCO synthesizer with 32 memory locations, while the Mono/Poly is a monophonic synthesizer with 4 VCOs and extensive modulation functions. Over 50,000 units of the Polysix, one of the first affordable polyphonic synthesizers, were sold, while only around 10,000 units of the Mono/Poly were sold.

Details

The components of the Mono/Poly are: VCO, VCF and VCA ICs from the US manufacturer SSM (which were also installed in the Prophet-5, but later replaced by Curtis chips). Signal generation and signal flow are structured in a subtractive manner: Four analog VCOs (SSM 2033) generate the waveforms triangle, sawtooth and square with variable and modulatable pulse width. A 24 dB/oct. low-pass filter (SSM 2044) has the parameters frequency, resonance, envelope intensity and keytrack (0-150 %). The VCA has an ADSR envelope where single and multiple triggers can be selected and an auto-damp function can be activated. Sync and/or cross modulation of OSC 1 to 2, 3, 4 or 1 to 2 and 3 to 4 can be set, as well as cross and frequency modulation via VCF-EG or LFO. Also built in are an MG1 modulation generator with triangle, sawtooth and square waveforms and an MG2 with triangle oscillation, which controls the pulse width of all oscillators and/or the speed of the arpeggiator.
(Source: Amazona)