Which ones would they be? I've had a lot of amps run through here for comparisons, and the good Class D (Purifi, Orchard, nCore...) and good Class A/AB didn't sound any different.
That's the problem, I haven't heard any that are known names here in the USA. & those that I have heard sound just like bad implementations of something. I don't fill my brain with the names of things I don't feel are right. I do know that it is not any of the names that I see here or I would recognize the name. Just like there is a ton of any other type of amp that I think does not sound up to par A/B or whatever, I am sure that if I heard one that sounded good, I would know the name because I would look into it. I did not say that they are all bad. I just said that the very few that I had heard were not what I would consider good. I have spent from 2001-2018 mostly living in places where less than 30% of the people had a cell phone, much less a decent sound system. When my old Klipsch Pro Media 2.1 computer sound system is better than 99.99% of what I am going to hear in any given month... then you know the audio scene in the places I have been living is non-existent. When my ADVENT 300, and a COBY cd player with a pair of ancient Radio Shack Minimus 7's is the best sound system thing they've ever heard...You know the class D stuff that is there is in fact worse. I would love to hear some good class D. In the Charleston, SC area, when I was here in the 70's, 80's, 90's there was a vibrant Audio community (& a few Audo & Audio/Video clubs. I the USA for islands on the Indian Ocean & then in the Western Pacific & I came back to this area and it seems to be an Audio dessert. It seems that I would have to travel to Charlotte, Atlanta or somewhere in Florida to hear other than what I have. I've been back over 3 & 1/2 years & I have met 2 people who have very good sounding systems. Most people that I run into have something that is not even up to the standard of a Bose tabletop stereo.