[cctalk] Re: Talking PDP11

The Synclavier I was commercially available in 1977, based off the Dartmouth Digital Synthesizer of earlier times. The core was a New England Digital minicomputer architecture (they did sell just the minicomputer to the military, as a side). The truth is that there were quite a few digital synths in labs in 1977. -- Will On Tue, Jul 11, 2023 at 10:22 AM W2HX via cctalk <cctalk(a)classiccmp.org> wrote: from the PLATO system at the University of Illinois that are perhaps the earliest of all in their category and not all that well known. four voice, 7 levels per voice, square wave synthesizer. It's fully documented in Sherwin's US patent 4,206,675. That one was attached to the auxiliary device port of a PLATO terminal and driven from the host computer, at 1200 bps. It worked quite well for playing music and was widely used for music education. It's a very simple device as you can see from the full schematics (which are, surprisingly, given in the patent). That patent was filed in 1977 but the invention is somewhat older, perhaps 1975 or 1976. unfortunately not well documented. That's a 16 voice programmable waveform (256 words by 16 bits per voice), more levels (256?), driven as a peripheral off the 8080-based "programmable PLATO terminal" from a program running in that terminal. So the musical score level definition of what to play still came from the host, still at 1200 bps, but the attack/decay etc. shaping would happen in the terminal. That one was a bit of an electrical muddle, with memory, logic, and D/A per voice followed by a 16 input combiner. Getting the analog parts to work right was a hairy task with far too many trimpots. Sherwin vowed that any followup would be digital all the way to one final D/A, which of course later became the answer in the PC sound cards, but if he did that it was after I left. The GCS was built around 1977. There were some interesting related pieces of work, such as a speed-sensing piano keyboard (so unlike an electronic organ you could have dynamics, exactly as on a piano), a music editing system with a score printing program to print on a dot matric (electrostatic) printer, and some other stuff. digital music synthesizer, but if not it is close.