early JP-4 filters and all JP-4 envelope generators use the now rare BA662 VCA chips, they're starting to be reverse engineered by multiple third parties. The Jupiter-4 had ten preset sounds and also featured eight memory locations for user-created patches. Saving to those locations requires two widely separated write record buttons to be held, to protect against accidental writing. A battery located deep between the chorus and power supply preserves the contents of the memory ICs. The controls to the right of the arpeggiator are only live when the yellow manual button is selected. While all of the switches, sliders and potentiometers are analog, these controls interface digitally through the use of analog to digital converts in the signal path. They are supplied with hi/low logic voltages or 0–5 volt voltages. Multiplexers and analog to digital converters read the settings, then send them in digital form to the microcontroller. The microcontroller then converts these parameters to analog control voltages, and sends them to the voice cards and envelope gates. Despite being a relatively early synthesizer with hybrid digital control, it remains relatively stable. Due to the low cost of the synthesizer, it managed to find its way into the hands of various musicians of the time, most of which were associated with the new wave and synthpop music scenes (see below). Philip Oakey of The Human League said of the Jupiter-4: "Ian also got a Jupiter 4 during the course of the recording but he took it away with him. What a fantastic, underrated synth that was. It was like a home organ with its horrible fake wood panels — eight programmable memories and eight presets!" Promars In 1979, Roland released a two-oscillator monophonic synthesizer called the Promars, which is often considered a monophonic version of the Jupiter-4. The Promars did not have the Jupiter-4's arpeggiator or its "ensemble" chorus effect, and reduced the four voice cards to two with basic detune. It had the memory and preset selection buttons above the keyboard, which were less clumsy to use than those on the Jupiter-4 which were intended to be used on top of an organ. It also had 37 keys, making it slightly smaller than the Jupiter-4. The Promars was used by Depeche Mode (around early-mid 1982), Vangelis (early/mid 1980s), The Enid, Jethro Tull, Landscape and Spandau Ballet (synth lead on 'To Cut a Long Story Short'). Notable users References