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Sequential Circuits Pro One synthesizer and manual

Photo(s) by Corey Holms. Imported from Flickr on Oct 3, 2016. Artwork published in
circa 1989
Sequential Circuits Pro One synthesizer and manual 1
Source: Uploaded to Flickr by Corey Holms and tagged with “stop”. License: CC BY-NC-ND.

Sequential Circuits (later Sequential) is an American synthesizer company founded in 1974. The brand is best known for the Prophet-5, the first orogrammable polyphonic synthesizer, used by artists including Michael Jackson, Madonna, and John Carpenter. This Pro-One model was released in the late 1980s.

Sequential Circuits Pro One synthesizer and manual 2
Source: Speculos. License: CC BY.
Sequential Circuits Pro One synthesizer and manual 3
Source: Photo by Corey Holms. License: CC BY-NC-ND.


  • Stop
  • American Uncial Initials
  • Chelmsford



Artwork location

7 Comments on “Sequential Circuits Pro One synthesizer and manual”

  1. This is great (and I like synths, too), but I have to point out that it’s not really Optima, but a knock-off called Chelmsford, produced by Addressograph-Multigraph (AM) in the seventies for their phototypesetting machines. I can always spot it because of the stroke extension at the top of the cap A. Other identifying marks are a stroke extending to the inside of the cap Q and different quote marks. It disappeared with the rise of desktop publishing.

    Also, something you don’t really see anymore that used to be quite common is the use of a tilde as a hyphen (on Pro-One here). I think it was from people using rub-down type (and maybe headline setters) who thought it looked cooler than a normal hyphen.

  2. Thanks, Mark! I also couldn’t ID the face used for the text in this manual. Corey posted more photos.

  3. I’ve seen it before, but I’m not sure what it is either. I think it may be from some kind of strike-on typesetter or proportional typewriter. I have an old Varityper brochure, but it doesn’t show all the styles available, and not this one.

  4. Wasn’t sure I had it, but I found a copy of an AM specimen booklet from 1976 in my archives. It shows a sample of Chelmsford at about 12pt.:

    AM Chelmsford (Optima clone), specimen from 1976

    One difference I’d forgotten about is the hook on the lowercase y. I have never been a big fan of Optima, but I hated what they did to it.

  5. Thanks, Mark!

    This iniquity was digitized as Chlmsford [sic] by The Font Company in 1990 — with that ‘A’ and ‘y’, but a more faithful ‘Q’. Devroye credits it to URW. URW++ still sells a variation for engraving named DTC Chelmsford 4-line, made by Volker Schnebel in 1995.

  6. There is a trucking company in my area called Quast that used it for their logo for a long time. All caps, so you got two of the offending glyphs in it.…

    It would make me a little annoyed whenever I saw it.

  7. Mark, is the text serif from this manual in your AM catalog too?

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