Brochure scan in via
Brian Kehew.
This is a scan of a product flyer for the the Sequential Circuits Model 600 Sequencer and Complex Wave Generator. It is first image of the unit shared on the internet that I am aware of (
click here for a search). It was Sequential Circuits first product. Approximately only four units were made a couple of years prior to the
Model 800.
An interesting side note is the aesthetics of the unit. See if you can spot what's missing before you read on. Sequential Circuits (along with Oberheim) started out creating products to work with existing synthesizers at the time. So what's missing? The trademark knobs and section outlines. It wasn't until the
Model 700 programmer in 1977 that we begin to see what was to become Sequential Circuits trademark look. Another interesting side note is that the model numbers for Sequential Circuits first three products where not actually sequential, the Model 600 (1974), the Model 800 (1975), and the Model 700 (1977). They broke out of the "Model" line for the name with the Prophet-5 (which was the Model 1000) in 1978, but came back once with the
Model 64 Sequencer for the Commodore 64 in 1983. One final thing I thought was kind of neat was that the final bullet point in the brochure called out how the Model 600 made for an excellent teaching aid for electronic music. Indeed.
The following is the description from the scan (note the reference to the unit as a teaching aid):
"MODEL 600 SEQUENCER and COMPLEX WAVE GENERATOR
As A Sequencer -
- Three rows of 16 controls, each row with its own output.
- Built-in sequential control for up to 48 note sequences by turning only one knob.
- Voltage controlled clock can be set internally and/or controlled externally.
Patch one output row back to the VCO input, and the length of each note can be precisely controlled.
- Can sequence slower than one pulse every 30 seconds through and beyond the entire audio range.
- Any one level can be skipped by simply throwing its corresponding switch; hence, any combination of levels can be set.
- Direction switch for forward or backwards direction.
- Handy three-way mixers at the output for easy patch changes.
- LED (light emitting diode) visual display.
- Switch trigger output compatible with Moog synthesizers, including the Mini-Moog.
By flipping one switch, gate and trigger outputs can be obtained for other synthesizers, suck as the ARP 2600.
As A Complex Waveform Generator -
- The quality of the Model 600 makes it possible to be used as a complex waveform generator, with up to 48 segments constructing the composite waveform. Below is an oscilloscope plot of a 48 segment sine wave at 300 hertz, with the lower wave-form the output after being run through a low-pass filter.
- One can easily see the possibility for complete waveform control. With an internal adjustment, the external input can be adjusted to the standard 1 volt/octave; hence, the sequencer can actually be played as an oscillator by any keyboard.
- This capability makes the Model 600 an excellent teaching aid for electronic music, as well as a quality waveform generator for the perfectionist synthesizer performer."
via the seller: "I am selling this as non-working unit.It powers up.I think the problem is with the internal clock not working.There is a guy on You Tube who talks about this problem [possibly here, here, or here]. You can manually step through the events.All switches seam to be working .I don't have an analog keyboard anymore,so I can't input any notes or play anything out.I've taken a few pictures showing different numbers and lights on the display.These units are very rare..There were only less than 500 made.Mine is SN 072 .I also have the start/stop foot switch.This unit is also made for the US market (110v).Unlike the other unit listed from Japan that needs a power converter.I was the only owner.It sat in my smoke free personal studio for years.Then it was packed away.I might even have a photo copy of the circuit diagram somewhere that I will include if I find it.There is some scratches and nicks.But for as old as it is ,it's in good shape.No broken switches.All LED's light up.
"This is a very rare Sequential Circuits Model 700 Programmer designed to work in tandem with synths like Arp 2600s, Minimoogs (with CV) and other analog synths that didn't have the ability to store patches to have some of that capability. It includes a lot of great on board features. This particular unit still has the box and was barely used making it very close to new for such a vintage piece from the late 70s! Here's more info: RARE SEQUENTIAL CIRCUITS 700 SYNTHESIZER MEMORY / PROGRAMMER This vintage analog synth programmer was designed and developed by Dave Smith, founder of Sequential Circuits back in the later part of the 1970's. This particular unit was used on a Mini-Moog to assist in live performances and offered extremely swift and accurate recalls of analog synthesizer parameters. Overall, I'd say that this unit ranks a 7 out of 10 due to some of the lettering has worn off the front panel, there's a few light scratches, and there is a small amount tape residue on the top of the real panel [see photos]. Unfortunately I was unable to test it but was working fine and trouble-free when it put in storage - a bedroom closet - about 10 or so years ago so I can not say if it's working or not [However, When last used, it offered smooth, easy and trouble-free operation]. The unit powers up and the red LED display is strong & bright and the unit steps through the bank & program numbers like it's supposed to. It has the original, knobs, pots, switches and lighted push-buttons - All in working condition with a nice, rugged feel. Serial number is which I believe indicates that this unit was one of the first ever produced of the 700 series. I have recently been told that only 25 of these units were made so here's your chance to own a piece of Sequential Circuits early history. Below is a brief description and info I found on-line 
"Exceedingly rare Sequential Circuits Model 800 - Excellent used condition, one owner, only light use. All switches, LED's, display, and knobs work as they should, fully tested. All switches and jacks cleaned. All memory banks tested through all 16 steps with no record or playback issues. Switch works perfectly, with no issues. An amazing piece of equipment for CV/gate controlled synths. A great collector's example of the evolution of synthesizers!"
" The Sequential Model 800 Sequencer is a 256-event cv/gate sequencer based on microprocessor technology. This was probably Sequential's first product. Dave Smith started making these units in his garage. A cv/gate sequencer based on microprocessor technology. First known product from Sequential Circuits. Less than 500 units were produced between 1977 and 1980 starting in Dave Smith's garage.
This is serial number 0330, and was recently refurbished by synth maestro Dave Brown at Modular Synthesis..jpg)
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via this auction
"1984 - 1985 Vintage Sequential Circuits SIX TRAK synthesizer Model: Prophet 610 in the original box... This 4 octave keyboard comes equipped with midi in and out and when linked to a drum tack machine, combines the multi-timbred ensemble with a programmable rhythm section. Each sequencer (A or B holding six separate traks) allows for an 800 note memory allocation per sequence, and this memory storage can be increased to 4000 notes when combined with a model 64 sequencer. Of course, with midi, the playing field is wide open to many possibilities that go beyond the two I have mentioned. The back panel also includes audio out which can also be used for a head phone jack or a speaker output, and a footswitch controller jack is also present. The foot switch is not provided, but is an inexpensive purchase that can be obtained through any music store. This fun machine also includes a pitch and modulation wheel, polyphonic and unison mode functionality, programmable track speed and volume, track erase, memory – full warning, legato function, voice stacking, a flexible arpeggiator and 100 ready –to-play factory programs." 
