Class D = Trash?

" Interestingly Primare i32 intergrated amp,that is a Class D design, and got very good reviews here in Europe since its release 5 or 6 years ago, will probably be replaced with a new model later this month."

No wonder why my humble bid was accepted. I wish the damn thing would arrive, already, so I could quit reading and get back to listening.

A high-definition eGaN FET-based system with higher PWM switching frequency, reduced feedback, and higher bandwidth produces the sound that has the warmth and sonic quality that audiophiles demand;

For a quality Class D audio solution, it is possible to avoid these transitions all the way through the system to the final Output Filter

The key to great Class-d, is to get it’s LOW ORDER output filter to do it’s job of getting rid of ALL switching noise from the audio band before it get sent to the speakers, and without creating any phase shift.
The only way to do this successfully is to raise the switching frequency noise much higher so this low order output filter (without masses of feedback) can do it’s job properly without any residue effects or switching noise remnants being left within the audio band.

This is why Technics have led the way with the new SE-R1, have striven to DOUBLED the switching frequency with these new eGan Fet transistors, to get closer to the ideal above results.

Credit to Mark Levinson a couple of years ago tried to solve this problem with todays switching frequency, by using much lager (to take the amps power) higher order output filters and less feedback, but it was a bit of a flop, with their very expensive. (see the size of the 4 x chokes for the higher order output filter for each monoblock).

http://www.stereophile.com/content/mark-levinson-no53-reference-monoblock-power-
amplifier#rJEmkELOsfXsME4b.97
It’s 10khz!! (not 1khz) square wave without!!! the AP filter, is the best ever seen for a class-d amp (almost as good as a linear amp) because of it’s massive higher order output filter and less feeback, but this high order filter obviously created other problems, and was not received well, that’s why low order with low feedback is the way to go, but it must do it’s job properly, and the only way to do that is to raise the switching frequency noise much much higher.

Cheers George

Hi @georgehifi

I'm not sure that feedback in a digital amp works the same way, or has the same consequences as it does in a linear amplifier.

Do you have any data that indicates feedback is anything but a positive in a digital amplifier?


Best,


E

No but I believe from what others have said, the output filter in some Class-D’s is included into it’s global loop aiding it’s effectiveness? that's why I bought it up, just to cover all bases.

Cheers George

Ahhh, makes sense, and yes indeed it does. :)

Thanks for the clarification.