From james_eaton@btopenworld.com Thu Dec 13 06:19:32 2012
Subject:Re: Korg CX-3 analog vs digital?

Some of the problems with electronic organs were: keying, tone shaping and beehiving (crosstalk).

The CX-3 keyed square waves (or staircase?) in the custom chips and then filtered, so it sounds quite flutey, thin and hollow. Keying square waves is easier and cheaper (and therefore smaller and lighter) than keying other waveforms (such as sine-like shapes) because distortion in the keying circuit doesn't affect the waveform. HS have avoided this problem on the new B3 since it uses metal-metal keying. Also their approach gives natural click. A company made a MIDI module using a Hammond TG with some electronic keying circuitry added so this approach is feasible at least maybe using CMOS switches. The demos sounded pretty good.

Getting a sound close to the output from a tonewheel will need some heavy filtering or some kind of active shaping circuitry using the output from your pitch generation for timing pulses. This could be a lot of circuitry if each filter has a couple of op-amps and filter caps.

Beehiving will be a consequence of how this is wired up. It will sound different to the leakage and crosstalk on a B3 but it might still be acceptable.

So this will be a very interesting project but how commercially viable will it be? With today's DSP-based instruments, if the manufacturer finds a better model they just release some more software. Not so with a H/W-based instrument...