The first electro-mechanical desktop synthesizer

The first electro-mechanical desktop synthesizer
gamechangeraudio.com

>This is one of the Synth's eight motor oscillators. It can produce four distinct waveforms - the optical disc creates sine, saw and square waves through reading wave reflections via infra-red sensors while the electromagnetic pickups at each motor's base produce the inductive "M" waveform.

The picture shows a small motor driving a physical "strobe" disk printed with 3 different patterns, which are read by optical sensors to create the electrical sine, saw and square waves whose frequency depends on the motor RPM at the time.

The electromagnetic pickups at the bottom of the motor apparently generate an "M" shaped wave as the motor turns. This is the one that's conceptually similar to the original Hammond organ starting from 1935 which also did mechano-electrical waveform synthesis.[0] Although the Hammond motor ran at constant speed synchronized to the power line frequency. The Hammond had a metal disk for each note of the musical scale, precision machined like gears so each note would be at the proper pitch, and the lobes of the disks create the periodic magnetic induction to the pickups which generate the repetitive waveforms.

Definitely not a desktop instrument, a Hammond can be as big as a desk itself, and even heavier. But it was a true synthesizer.

It was also in the 1930's when Hewlett & Packard started up and developed their electrical frequency generator, where a single vacuum tube triode can be wired as an oscillator and used as the source of precision waveforms at a frequency of choice. Making it directly possible for someone to construct a fully electronic organ along the same lines. A musical instrument like this would be a more modern milestone.

So about 20 years later once the patents on these type circuits expired, Thomas organs began to appear in the 1950's where each note had its own triode, so it was a very early organ which was truly a fully electronic synthesizer.

Still didn't sound as good as the Hammonds, but Hammond had decades of absolute top continuous improvement in engineering by then.

[0] Also somewhat analogous to a crankcase position sensor on an internal combustion engine.

https://en.wikipedia.org/wiki/Tonewheel

Any motor-based oscillator can be accurately emulated by a digital oscillator, so the answer to the original question is "nothing." But yeah, neither is good enough to emulate a trumpet played by a human.