- why is 768 kHz better than 500 kHz?Theoreticallly, having an integrated amp in which the digital audio signal is upscaled to 32bit @768kHz and converted to a Three level PWM to drive an GaN based full bridge power stage, where the volume control is implemented by digitally controlling the DC rail voltage of the power supply while feeding a full scale unatinuated digital signal to the PWM modulator, should be the best possible class d implementation. Too bad no such amp exists...
- how do you deal with the non linearity of the PWM conversion?
- how do you deal with the non linearity of the power stage?
- how do you deal with the non linearity of the output filter?
- how do you deal with the load dependence of the output filter?
- how do you deal with the response time of the power supply?
- and so many other questions...
Since I feel a lot of creativity in this thread, here are some publications of a very creative guy who actually happens to do the best class D amplifiers of the world:
https://www.hypex.nl/p/application-notes-white-papers/
That's a good starter to understand the real issues behind class D