(10-05-2020, 04:17 PM)Mike Watterson Wrote: Class D can now be better than Class AB or Class B for audio. Class A is relatively easy
All depends. They Hypex NCORE are a superb class D product with stunning specifications. They are fairly cheap at Euro275 each, and will push out 400W into 4 ohms. The exceptionally low distortion residual is flat with frequency, and lacks the rising distortion at higher audio frequencies that class B does (and class A too).
The only way that you can pull that sort of trick with a conventional power amp is to use feedforward error correction. Difficult to do, and keep an amp stable and not oscillate at MHz. There are only a few that manage sub ppm distortion across all audio frequencies this way - and not within orders of magnitude of the cost of an NCORE.
There is however an interesting topology however here https://neurochrome.com/products/modulus-686 that gives the same sort of performance as the NCORE at around the same price, using chip power amps (LM3886), but with a mildly rising distortion above 5kHz.
Craig
