This sort of thing can be done with more accuracy using samples, but modelling the various aspects of tape degradation and other aspects of the sound offers a bit more user control. The tape degradation techniques can also be used in tape echo emulations.
Pitch Bend wheel also controls the Pitch widget.
It’s really cool !
Would it be better to start from a “clean” sample and apply degradation after that
(side question : where do we find “clean” mellotron samples… )
Well, this instrument isn’t using samples at all, it synthesises the sound. You can get a clean sound by reducing the crackle, hum, wow and hiss levels to zero. The single-cycle wavetables are based on analyses of downloaded mellotron samples, but this procedure effectively removes any noise.
Nord bought the licence for the original Mellotron/Chamberlin tapes a while back so I would have thought this would mean that they would have the most pristine versions, but upon listening to the demo of the flutes sound on their website, it still sounds pretty grungy. I guess we have to just accept this as part of the sound!