Yeah. I used to think it was all psycho-acoustics until I had the chance to a/b them indoors with high end speakers so its the exact environment and drivers on axis and no ambient noise. The tweeters on my ref speakers are vifa xt rings so they extend far past my audible range. Its very clear amps sound different, but the difference may not be significant for most to acknowledge or value.

there is a point of diminishing returns but if I can fit it, Im always going to prefer a/b on my full range speakers. Even the current Sony GS 4 channel is a small class a/b that sounds excellent. The Audio Designs ADS60.4 I have is very impressive.

Class D can sound as good as A/B,but not better than a well designed a/b amp...On this site the mosconi zeros are a good example of an a/b amp that will sound better than 90% of any amplifiers and all class d amps. But for me, old school zapcos. The zapco set below were my all time fav amps. Like someone else said...Oz Audio and zapco were magical together as was the focal Utopia and zapco studio 300x and 150s or the Z/Comp Zaps amp seen below .I went to an old school Directed pre sellout 5 channel to have an all in one chassis amp and the focals became brittle. Back in the zapcos. Story of my Car audio history. Aways chasing the Oz Audio/Zapco VW Scirroco system I had in the 90s.

I have a Malaysian Clarion/Addzest Pro Audio amp on the way to test.

Some pics of it. Also a/b with class a bias.