This Jupiter-4 has been has been serviced in-house and is fully functional. It plays very well and in excellent condition with minimal wear to the veneer end cheeks. It is a european model rated for 220V AC and in an effort to maintain it's original integrity, it has not modified to alter this, but will include a step down transformer to run properly US AC mains voltage.
The Roland Jupiter 4 Compuphonic Synthesizer is a vintage four-voice polyphonic synthesizer from 1978. The Jupiter 4 was notable as the company’s first self-contained polyphonic synthesizer, and for containing digital control of analog circuits (termed “Compuphonic” by Roland), allowing for such features as programmable memory and voice assignment modes. It's sounds are lush and far reaching.
The Jupiter 4′s architecture is 4 identical voice cards, each with a VCO (with sub-oscillator), resonant low pass VCF (which can self-oscillate), and VCA. Modulation includes an ADSR envelope and LFO. The LFO, routable to oscillator pitch, pulse width, filter cutoff and amplifier, is notable for being able to reach audio frequencies, allowing for crude FM and AM synthesis. The final signal path includes a high pass filter and stereo chorus effect.
The Jupiter 4′s two most distinctive features are provided by virtue of its “compuphonic” digital control of the four voice cards: An arpeggiator, with a choice of up, down, up/down, or random mode. The Four voice assignment modes include 1 VCO-per-voice polyphony, 4 VCO unison, 2 VCOs duophonic, and 1-VCO per voice when three or four keys are pressed.
- 4 voices
- 1 VCO per voice (triangle, square, square with PWM) and a switchable on\off sub osc 1
- LFO (sine, square, ramp up and ramp down)
- HP filter
- LP resonant filter
- 2 env (ADSR) one for the filter, which you can invert, one for the VCA
- Memory: 10 preset and 8 user writable patches