Class A or Class D solid-state amplifiers (modern designs)

Julian Verker founder -Vereker considered Naim amplifiers belong to the "class B" category where bias current is minimized. Sounds fantastic  ;^)

Merrill Audio makes very nice class D. 

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I can’t do better than Atmasphere’s response. But I will add my 2 cents. I have built several Nelson Pass diy designs, both power amps and preamps, all Class A of course, and I use them in two different systems in my home. I will say there is a sweetness to these amps, but I will also say it could well be that it is due to their relatively low power. These are such simple circuits they are “messing” less with the signal. Pair them with a speaker in the 95 dB sensitivity range and you’ve got a winner, IMO. But move on to my listening room, and Class D shows up, a Rogue amp with their combo of a tube input stage and Class D output stage. That’s largely because I prefer Magnepan speakers for serious listening and they need power. And I see no sense in running a Class A amp with anything close to 100 watts. For one, the constant draw of electricity is contrary to any semblance of environmentally responsible energy use. And I auditioned plenty of amps, and find these hidebound descriptions of the supposed differences in amp classes comical. Honestly, it’s like your mechanic in the 1970s and 80s advising you to buy an American car with a V-8. Sure, he’s an expert, but in what? Why, fixing trouble-prone American cars, of course. Technology changes. Better ideas come along. Class D is one of those. 

Truth is individual due to how hearing is constructed within the individual mind and individual body... therefore... to some real extent... it will inevitably remain JAFA.

(Just Another F-ng Amplifier)

I currently have a Cherry STM designed by the late Tommy O'Brian of Digital Amp Company. I have the Audiolab 600cdt to Schitt Bifrost 2 to Tekton  Lore Be speakers. This class D Amp with this setup sounds great. 

 I think most AB amps operate in class A mode up to roughly 1/10th of their full power output.  Which is to say 10dB less than peak output. So for most listening you hear only class A, and save money on your power bill.