A polyphonic analog synth introduced by Korg in 1983; it was intended to hit a price point beneath that of the Polysix. Korg worked at cost reduction with this model, producing a more affordable synth with some design compromises. The synth had six voices and patch memory with 64 memory locations, and a cassette interface for loading and saving patch data.
The voice architecture consisted of a pair of digitally controlled oscillators (DCOs), a voltage controlled filter, a voltage controlled amplifier, and an envelope generator, per voice. (The Poly-61 was Korg's first synth to use DCOs. It is notable that, even though the Poly-61 was intended to be less expensive than the Polysix, the Poly-61 provided two DCOs per voice, as opposed to the Polysix's single VCO per voice.) There was one low frequency oscillator. The keyboard spanned five octaves, C to C. In place of a conventional set of pitch and mod wheels, the Poly-61 provided a joystick. Moving the joystick did pitch bend up and down; pushing it away from the performer routed the LFO to DCO frequency to produce vibrato, and pulling it towards the performer routed the LFO to the VCF cutoff frequency. (Many subsequent Korg models have used some variation of the joystick for pitch bend and modulation control.) The Poly-61 carried over the arpeggiator from the Polysix, and a built-in chorus effect was available.
The user interface for patch editing was a variation of the one-knob interface. A pair of up/down incrementing buttons selected a parameter to be edited, and another pair of buttons increased or decreased the value. In order to make the parameter control and memorization circuity less expensive, the synth quantized most of the parameters to only 2 or 3 bits (4 or 8 possible values), which was insufficient precision for some parameters; one that many performers complained about was VCF resonance, which had only 7 possible settings. Parameters were selected by number; a map on the panel provided the parameter numbers, and range of values, for each parameter. The editing interface and the limited precision of some parameters somewhat limited the Poly-61's appeal, compared to the competing Roland models, although the Poly-61 still sold well.
In 1984, the model was upgraded with a rather basic factory-installed MIDI interface, Korg's first model to do so. This was designated the Poly-61M, and was identical to the earlier model other than the MIDI and a somewhat revised case paint scheme. This remained in production until 1986.