Ads something that lags the signal between midi reciever and freq. Modulation. Dont remember which device to use.. Same technique should be usable on all kind of midi to modulation.
If you don't have Flexor you can use the Creamware 6db LPF, and although it is touchy all of the action is in the far left position, then move it ever so slightly.
I use it for Seperat Oscillator Glide also as it will add Lag to OSC 1, and as many OSCs as you like.
I think I figured it out. However, in the end it turns out it's probably the controller on my keyboard thats worn. It's a Roland A90, and it's got both a modulation lever, and wheels. There's no zipping when I use the pitch wheel
I had an A90, those ar excellent controllers, not like the disposable ones they serve these days. Not a bad Piano either, I believe it was Jerry Coakleys 16MB version of his EMU 128MB one. Roland could compress samples to PCM really well.
Dont get rid of that as you'll never see anything that good agin unless its 4000 USD.