Atma-Sphere Class D… Amazing

Why is the power supply not a switch mode? I see a large selection of supposedly well designed, medical grade SMPS, by Traco or Meanwell. Yet, I see class A or class D amps not using these. Why?

Most class d amp makers do use smps. There are a handful that use an old school traditional tranny, bridge, etc. If your amp module design is well done with a high PSRR, it makes little difference, according to experts like Bruno Putzeys, who uses smps exclusively with ncore and purifi. They have many good points but some still believe an amp isn't any good if it doesn't weigh 50 kg.

there is NO common knowledge

Wrong, there is a lot of common knowledge. There is no common opinion on what sounds "best" thus a market full of products of different designs, classes, power supplies etc. It's not a lack of knowledge but a wealth of knowledge that allows manufacturers to produce products that appeal to a broad market full of consumers with widely varying tastes.

Real KNOWLEDGE in audio.......is how something sounds......there is no common Knowledge of sound.....because there are so many variables......believe it or not.  There is lots of technical knowledge.....but that does not necessarily correlate to sound quality....

Are there clear evidences of the superiority of one GaN amp over other GaN amps?

Concentrating just on GaN amps,  the observations made for Atmosphere GaN monos may well be applied to a number of other GaN amps. I honestly can see no proof of superiority except that I read a number of  subjective expressions. I readily believe that Atmosphere d amps sound wonderful, and would really like to know more on how much better are they than the other GaN amps. This thread, so far, didn't help me in this. Too many subjective points of view. I think it is not timely comparisons with tube stuff, SS can hardly give you the same lightness, 3 dimensionality and body. These are just two different concepts, you may like one more or the other. I like tube gear more but also enjoy in some degree class d, which i trust gives the best in SS.

@pstores , did you really made an ab comparison of Atmosphere class d with the Peachtree or Voyager, or some other GaN amp?

All GaN amps will sound completly different from every other GaN amp and also all Class D amps using mosfets......the GaN transistor may be one thing that improves sound but it is just one of an infinite number things that change the sound.

Here is a list of my candidates for excellent class D amps at lower prices (under $10K)

1. The VTV Purifi Eval amp.....around $1200

2. Orchard mono blocks (GaN amps) $1500

3. VTV Purifi stereo amp using the New Purifi ET704 modules and discrete input stages using the better Sparko labs op amps, Sparko labs discrete regulators and WBT negtgen jacks.....$2100

4. Dual mono stereo version of above. $2260 or mono blocks $2600

5. Orchard Audio Starkrimson Stereo Ultra (GaN based).....starting at $2500 for basic stereo....options for dual mono and extra capacitance....

6. Peachtree GaN 400 and LSA Voyager amps (GaN based)....basically the same amp with the same modules and power supply $3K or less

7. The Atmasphere GaN mono block $5400 the pair

8. AGD mono block Audion GaN based amps.....$7500 the pair.

9. Hopefully soon to be released.... the Mytek Manhattan amp....stereo amp using GaNs.....something like $7K.

These need to be all compared with each other.....Who is volunteering?

Here is a real sleeper....and maybe a super amp?:

Peachtree has just released a The Gan 1 class D amp that has NO FEEDBACK....no op amps......it is pure digital. Takes PCM via coax only and converts it to PWM in software and uses GAN output stage. NO feedback. This will not have a low of impedance as some of the above and also the distortion figures will be worse than above (Kuribo will freak out at this). However, the sound is said to be really great. You need a source that has some kind of digital volume control at 32 bits or more so you won’t mess up the sound. This thing requires no DAC, no preamp....no cables between DAC and Preamp and amp.....This is exactly what the Technics amps do and also the Lyndorf amps do. There is only a few delivered so comparisons to any serious DAC/Preamp/amp combos have not been made.....but I always like a short signal path.....let’s see what this $2000 amp that needs no DAC or Preamp can do.