Notes on “The Design, Construction, and Operation of an Electronic Music Synthesizer”

This report was originally written to get course credit for an independent study project that I did my senior year in Electrical Engineering at Tufts University. It was written in 1977, and the device that it describes was designed and completed in the summer of 1976. It represents the first stages in my exploration of modular synthesizers. After completing my Ph.D. work in physics four years later, I found myself drawn again into designing and building synthesizer circuits during the early 80’s, resulting in the realization of more than twice as many modules that are considerably more advanced. Although I have more information on my larger system posted on a website (see http://www.media.mit.edu/~joep/synth.html ), I never formally documented the designs, hence this is the only readable written work on synthesizer circuits that I produced (note that my more current research directions that involve musical controllers are posted on the project site of my group: http://www.media.mit.edu/resenv/projects.html ). In the interest of posterity and for the benefit of hobbyists, I’m posting this document publicly. Admittedly, the designs are quite primitive compared to my subsequent modules and to where electronics has evolved. But some of the circuits are still a bit interesting in a quirky way… Some of the designs were inspired by other devices, either on the market as effects boxes, or circuits published in various places that I hacked and modified – I cited all such sources in this document (in effect, it served as an undergraduate thesis of sorts). After returning to the USA following my ETH postdoc at the end of 1983, I tweaked the design of the modules in this cabinet to improve their performance and bring their spec up to the newer modules – these changes are handscrawled atop the schematics (apologies, as not all are entirely legible, although the drift is usually clear). This synthesizer still exists as documented here and works wonderfully, except for the oscillators, which I replaced during the late 80’s with new designs based on the CEM 3340 VCO chips (the front panel is still the same, but the oscillator uses the Curtis chip, which is quite stable).

-- Joe Paradiso, July 2003 --