Prophet VS was Sequential's first foray into digital synthesis. Actually, you could say the Prophet 2000 was, but technically it was a sampler not a synth. The VS was the first synth to bring two-dimensional crossfading between waveforms into the mainstream. This interesting concept became known as vector synthesis. The Wavestation A/D expands upon the concept by allowing crossfading between wavesequences, not just individual waveforms. The keyboard version sports a 61-key velocity sensitive keyboard but no aftertouch. The VSes were rumored to have aftertouch when they were first produced, but I know of very few that still have working aftertouch - talk about a poor design. The VS is know most for its growling fat alaising basses, airy digital sounds, and due to the very nature of wavemixing (and the multistage looping envelopes), smooth evolving pads. Here's a rundown on the synth architecture: Each voice is comprised of four of the 128 cyclic 12 bit waveforms (32 in RAM), with 24db/oct filter and VCA courtesy of the one-chip wonder CEM3379. There are two LFOs per voice with triangle, saw, ramp, square, and random waveforms available. There are three multistage looping envelopes available, each hardwired to pitch, VCA, and VCF. The VS has a modulation matrix, and while not as extensive as I would prefer, is certainly better than predetermined routings. The hardware side of the VS strikes me as a bit strange and definitely "beats around the bush" so to say, to accomplish its goal. The unit uses a Motorola 68000 processor which is nothing extraordinary, and waveforms are stored in ROM. So what's wierd? For starters, the waveforms are "scanned" from memory ala early Emu/Ensoniq style and directly feed a D/A converter. Since there are four waveforms per voice, that means four voice ICs and four D/As. Next the four analog signals (muxed to handle all eight voices) are scaled by VCAs and then demuxed by CEM5510 octal fast sample and holds. From there they are mixed and then feed CEM3379 one-chip voice processors. The designers really seemed to have wasted a HUGE number of CVs, since the contol voltages for the wavemixing (8 voices x 4 waveforms = 32 channels) are demuxed with two CEM5530s, then consequently remuxed in sync with the CEM5510s to scale the waveforms. (to save on VCAs I suppose) If they would have just done the amplitude scaling in the digital domain they could have avoided using the CEM5530s (a terribly unreliable custom IC) along with eliminating the need for FOUR D/As, FOUR 5510s, and FOUR VCAs. Maybe an extra 68000 was cost prohibitive at the time, but I'd certainly think the extra hardware and PCB real estate cost more than one measly microprocessor. Oh well. I'd have done it differently. (Then again, I was twelve at the time.....) Note: Most VSes have ROM version 1.0 or 1.1, although Whine Country released version 1.2 which added MIDI LFO sync, program number memory, and a data inc/dec mode. One last interesting note: Apparently there was a ROM ver 1.3 in the works before SCI folded. The previous bay area owner of my VS had 1.3 replaced by 1.2 due to instability. Several new features were implemented in 1.3, but needed debugging. Dimensions: 38" x 15" x 4"     Weight: 36lbs Musician's Net Prophet VS Page Johan Torneheim's Prophet VS Page Prophet VS Design History The Dave Smith Synth Museum