Simple frequency-tunable spark generator?

by Logan R. Kearsley   Last Updated July 11, 2019 21:25 PM

This may sound weird, but...

I am attempting to design a steampunk / gothic horror-styled electric harpsichord, with sparkgaps as the sound source in the vein of musical Tesla coils.

Unlike musical Tesla coils, any particular spark generator need not be dynamically` tunable for different frequencies--there will be 88 of them, one per keyboard key, manually tuned to a single note at a time. I would prefer if the frequency could be tuned by screwing a threaded steel rod into or out of a solenoid to alter inductance, but a potentiometer or variable capacitor any other sort of mechanically-adjustable tuning component is acceptable. Also unlike musical Tesla coils, the sparks need not terminate in open air--and I imagine it's probably best if they don't, since there will be 88 of these things packed fairly close together.

To fit the aesthetic, it would be ideal if such a circuit could be constructed entirely out of resistors, capacitors, and inductors--i.e., discrete components that I can make by hand by winding wire into coils, rolling up laminated sheets of metal foil and paper, etc., but if a transistor or or diode or something is required per spark generator, so be it.

The intended behavior is that, on activating a switch (keyboard key), a spark should be generated which produces a specific audible tone, and either continues indefinitely while the switch is activated, or decays after a fixed but significant amount of time (analogous to a plucked string ringing down).

What is the simplest / most robust circuit I could build to do that?



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