MATRIXSYNTH: Motorola Scalatron Synthesizer

Saturday, January 05, 2008

Motorola Scalatron Synthesizer

via this auction

Anyone know what this is?

Update: be sure to check out the comments for more info.


  1. I'd heard of the Scalatron as an early microtonal synth:

    But I don't know about the TV. I'm guessing it's probably just a waveform display like an oscilloscope.

  2. Mark Vail Vintage Synthesizers book, page 101
    online at google books
    Herman Pedke designed it

    1. Herman J Pedtke, my father, invented the Scalatron. He was an organist (FAGO) and professor at DePaul University in Chicago. He loved harmonics and theory. The Scalatron was the focus of his ideas put into physical form with the technology of the time. He would say that he designed it so 7th century Chinese music could be played at the same scale and tuning as the original composition and performance. I believe that he achieved that though the lack of acceptance and enthusiasm made him feel unsuccessful. So great to see interest still in it. He died in 1992.

  3. The Motorola Scalatron was a dual rank keyboard based upon organ divide down technology, built into home organ type packaging, and invented by George Secor in the early 1970s. It had a cassette interface. I am not aware of a video interface, but it is possible it was added later. This auction is just for the monitor, not the keyboard, which would be a real find as less than 20 Scalatrons were ever made. Some versions of the keyboard used a hexagonal array rather than the standard piano style keyboard.

  4. Adding to this, one of the patent numbers does appear to match a pedal tone decay patent that is now reassigned to Yamaha, who went through a splurge of activity in patenting microtonal technology. So the device may be a legitimate attachment to the Scalatron.

    Patent 4085643 - Truncated decay system

    As the first knob on the monitor is labeled with a note symbol, I wonder if this was used to assist in retuning the microtonal scales in the Scalatron.

  5. I was working at Motorola at the time the Scalatron was being developed, I think in the early 1970's. This was one of a few "New Ventures" programs.

    The motto for the synthesizer was that it let you "play in the cracks", because you could play more than the usual 12 notes and experiment with unusual scales.

    The TV monitor was part of a piano tuning device, which was different from the synthesizer keyboard. It worked like a Conn strobotuner. It had a split screen, with fixed bars on the left side, representing true pitch, and vertically moving bars on the right side corresponding to the pitch of the instrument being tuned. You would tune the piano until the bars were stationary. There must have been another box connected to the TV monitor.



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