Operation is based on a non-hysteresis 5th order self-oscillating control loop taking feedback only at the speaker output.
Furthermore, the NC500 OEM is an unbuffered amplifier leaving the implementation of an input buffer up to the manufacturer. The NC500 is practically devoid of any sonic signature so this external buffer is a good way of tuning in a “house sound”.
It looks like in the Dragon they use the NC500. I assume they’re doing what every other manufacturer that uses this module they’re adding their sound with theirs or a third party external buffer. IMO it’s preferable to leave the signal as transparent as possible and not muck it up with distortion but to each his own.