by andyg » 17 Feb 2017 19:04
Earlier Casios had four positions for each drawbar, Off, Soft, Medium and Full. That would explain any jumpiness in the sounds. That hadn't changed by the last time I reviewed a Casio, the CTK7000.
As for release on drawbar sounds, strictly speaking, they should cut off abruptly when the key is released. That's how the Hammond tonewheel organ played and it's that 'direct drive' feeling that helps endear it to its legions of fans, and something that Hammond have worked hard to recreate on their digital clones. LSI Hammonds like the Concorde, Elegante etc, did introduce sustain and other drawbar based organs, but this was more for special effects. The organist, playing with a true legato touch, shouldn't need it for organ sounds. And there are times when you might want a crisp, non sustaining organ sound, along with sustained strings and piano - one of my 'trademark' sounds on Kawai, for example. There's no problem in implementing drawbar sustain, it's just a question of whether or not they wanted to.
I still haven't seen one in the flesh - or even an advert for one from a regular UK dealer. Thomann/DV247 seem to be the only dealer, and I'd guess they're shipping orders across from Germany.