[sdiy] Noob Question: Passive Filter Design

[Colin f]

> I have a circa 1967 Ace Tone "Rhythm Ace" FR-1 beat box - it 
> uses inductors for the various percussion voices.

Ditto the Korg Minipops 7.
PCB photo and schematics are here:
http://www.colinfraser.com/mp7/index.htm
Many of the sounds have no active components at all, or just a single
transistor buffer.
They are just resonant LC filters fed with trigger pulses.
Count the inductors.
Then think how long it would take you to wind them by hand.
Has anyone ever played with gyrator-based copies of this sort of thing ?

Cheers,
Colin f