The Jupiter-8, or JP-8, is an eight-voice polyphonic analog subtractive synthesizer introduced by Roland Corporation in early 1981. The Jupiter-8 was Roland's flagship synthesizer for the first half of the 1980s. Approximately 3,300 units have been produced. Although it lacked the soon-to-be standard of MIDI control, later production series of the Jupiter-8 did include Roland's proprietary DCB interface. The instrument had many advanced features for its time, including the ability to split the keyboard into two zones, with separate patches active on each zone. Two years after the release of the Jupiter-8, Roland released the more affordable Jupiter-6 synthesizer with built-in MIDI control but an otherwise slightly reduced set of features. In 2011, three decades after the release of the original Jupiter series, Roland released the fully digital Jupiter-80 and Jupiter-50 synthesizers as successors to the 1980s originals. They were in turn succeeded by the Jupiter-X and Jupiter-Xm in 2019. A Jupiter-8 plug-out was included already installed on the Roland System-8 synthesizer, in 2017.
Features and architecture The Jupiter-8 is an 8-voice polyphonic analog synthesizer. Each voice features two discrete VCOs with cross-modulation and sync, pulse-width modulation, a non-resonant high-pass filter, a resonant Low-pass filter with 2-pole (12 dB/octave) and 4-pole (24 dB/octave) settings, an LFO with variable waveforms and routings, and two envelope generators (one invertible). Features include adjustable polyphonic portamento and a hold function for infinite sustain of notes and arpeggios. A versatile arpeggiator can be synchronized with external equipment by using the proprietary Roland DCB interface, clock input via CV jacks on the rear panel. An assignable bender can be used to control pitch or filter frequency. The Jupiter-8 includes balanced XLR outputs as well as unbalanced 1/4" outputs for the ”Upper” and ”Lower” presets in Split mode. In addition to monophonic and polyphonic modes, the Jupiter-8 includes a unique polyphonic unison mode, in which all 16 oscillators can be stacked onto one note, but divide down if more keys are pressed. No other polyphonic synthesizer at the time had this feature. A Zilog Z80 CPU was used for managing storage of patches, scanning the keyboard and front-panel controls for changes, displaying the current patch number and other information on the display and taking care of the auto-tune function, among other operations. The VCF was based on the custom Roland IR3109 IC (also used in the filter circuits of the Jupiter-6, later Jupiter-4 and Promars units, MKS-80 rev 4, Juno-6/Juno-60/Juno-106, SH-101, MC-202, JX-3P and packaged in the 80017a chip used in the Juno-106 and MKS-30, among others). The VCA was the BA662, used also in Juno-6/60/106, JX-3P and TB-303. The envelopes were generated in hardware by the Roland IR3R01 chip (also in the Juno 6/60), and are much faster (1ms attack) than the software-generated envelopes used in the later Jupiter-6, Juno-106 and MKS-80 "Super Jupiter".
Reliability There are claims that early models had unstable tuning, mainly due to DAC board resolution. Beginning with serial number 171700, the 12-bit DAC was upgraded to a 14-bit DAC. This increased the resolution of the CV voltages that control the analog circuitry. The soldered-in battery typically lasts ten years or more, ranking these boards among the lowest-maintenance of their generation.
In the present day The wide range of sounds that the Jupiter-8 can produce, the efficient front panel layout (each synthesizer sound parameter adjustment had its own dedicated controller), and its sturdy construction, make the Jupiter-8 a venerable and desirable instrument even 35 years after it was first produced. Units in good condition still fetch significantly more at auction than most new synthesizers, suggesting that the Jupiter-8 will continue to be heard for years to come. While the characteristic sound of the Jupiter-8 can be heard on many songs from the early 1980s onward, it is still being recorded to this day. For example, Alicia Keys can be seen playing one in the video for her number one hit "No One" from September 2007.
Jupiter changes and successors
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