A polyphonic analog synthesizer made by the Italian company Elka, and produced from 1982 to 1985. It is often considered the finest product of the Italian synth industry. The Synthex resembles the Prophet-5 in terms general capabilities, but adds a number of features which were innovative for the time. Independent Italian synth designer Mario Maggi did the original design work on the Synthex independently, and then took the synth to Elka for manufacture. The Synthex was the first proper synth manufactured by Elka, which was noted for its electric organs and accordians (they had introduced the Rhapsody string synth the previous year).
The Synthex is an 8-voice synth with two oscillators per voice. Each voice also has a notable 4-pole multimode filter, a VCA, and two ADSR envelopes (one dedicated to the VCA and the other to the VCF). The synth had two low frequency oscillators, one with selectable waveforms and one outputting a triangle wave only. Routing for the LFOs was quite flexible. The oscillators were DCOs rather than VCOs; the Synthex was one of the first synths to use DCOs. They featured both soft and hard sync, and could also cross modulate each other. The VCF was implemented with the CEM 3320, and the Synthex was one of the few synths to take advantage of the
The Synthex was bitimbral (making it one of the first multitimbral synths), and had split keyboard capability. In the bitimbral mode, the synth was divided into two timbres each using 4 voices, and the two timbres could be layered, or each assigned to one half or the other of the split keyboard. There was also a (monotimbral) "double" mode, in which two voices were assigned to each key played, in effect stacking 4 oscillators per voice. An onboard chorus circuit with three settings was available to further thicken the sound.
Pitch and mod wheels are replaced by a joystick, which can be configured to route LFO signals to several destinations, and can be set to effect only the upper or lower half of the keyboard or both. The joystick is located at the lower left of the main panel; the convention location for performance controls at the left of the keyboard is taken up by the onboard sequencer, a very advanced design for its day. It had four separate tracks (which could be set to different lenghts). It supported real-time and step-entry editing. An early software revision allowed each track to be assigned individually to one of the two timbres in one of the bitimbral modes. Jacks on the rear panel allowed the sequencer to output its clock to synchronize other devices, or to be synchronized to an external clock.
80 patch memory locations were provided, plus a cassette interface which could be used to save both the patches and seqeuncer data. MIDI was not originally provided, being that the synth was introduced before the MIDI standard had been published. After the first 200 or so units, the Synthex began to be equipped with a "computer interface" on the rear panel. A device known as the "MIDI breakout box" eventually became available which connected to the computer interface and provided a rudimentary MIDI capability (only note, pitch wheel, and mod wheel messages were supported). Late in the production run, the MIDI breakout box circuitry was built into the synth. Other than the MIDI breakout box, no devices or software were ever made available for the computer interface.
The Synthex, with its distinctive banks of white pushbuttons on a black panel, was manufactured for only a short period of time, from 1982 to 1985. There was market resistance early on to a high-end synth from an Italian manufacturer, and many performers did not discover the synth until after Elka discontinued production. Among them was Stevie Wonder, for whom Elka built a one-off unit in 1988 (shortly before the company went out of business) using spares on hand. Other notable users include Jean-Michel Jarre, who used a Synthex as the sound source for his noted laser harp sound on his Rendez-Vous album. An estimated 900 were built. They are very rare and highly valued on the collector market today.