I went from Class D to Luxman A/AB - And most of what you think is wrong

Class D can be wonderful but in my experienced opinion, if it has a SMPS just forget it! Even my Mac Mini music server SMPS killed the sound, it now has a linear supply.

All highly rated Rowland class D amps have SMPS. When done properly SMPS is much quieter than linear power supply, not to mention line and load regulated while linear supply is not.
Rowland uses SMPS even in preamps, where efficiency is not important, just because they can be so quiet. Another example is Benchmark. Their products, known to be extremely quiet, contain SMPS. They were able to lower noise by 10dB in their DACs just by switching from linear supply to SMPS. AHB2, an extremely quiet power amp uses SMPS.

"Linear Power Supply", in fact, is a very primitive unregulated switcher operating at 120Hz and switching at max voltage, charging output capacitors with narrow current spikes of very high amplitude. It produces 120Hz ripple as well as very narrow switching spikes, both very difficult to filter out. Also, many believe that transformer has to be heavy to deliver a lot of current. It is all matter of frequency. Small 1" ferrite transformer operating at 100kHz can deliver as much power as huge transformer operating at 60Hz.

Yes, SMPS can be very bad, especially when in cheap/crude computer power supplies but can also be wonderful when done right. It is funny that anybody can think, that SMPS is not good enough for class D, while class D is modulated SMPS.

kijanki:

Yes I know SMPS’s are inherently regulated and can be very quiet but the crap noise (RF) kicked back is VERY VERY hard to stop and it fouls up (at least for me) everything I’ve ever heard them in when it comes to a high end system. A switching amp and SMPS are not the same thing. 

I have owned amps as stated before with similar ICE modules, one with linear, the other with the SMPS from the same manufacturer. Forget even running a signal through an amp with a SMPS, try this experiment if you have another amplifier with a linear supply. Power your system with the amplifier (linear or switching) that has a linear supply. Listen to a well recorded passage. Now take a device, amp or anything else with a SMPS and plug it in near your audio system. Now listen to the same passage. If you hear no difference, your experience is FAR different than mine.

It’s the type of noise that is so damaging with a SMPS. It’s akin to odd order harmonic distortion. Large amounts of even order harmonic distortion can be tolerated and sometimes even enjoyed, but odd order harmonics orders of magnitude lower can completely wreck a system. SMPS manufacturers and users of them like to tout the noise levels but what they always fail to discuss is that the noise in linear supplies is MUCH MUCH more benign that the noise from a SMPS. 

Manufacturers like SMSP’s because they are cheap, and don’t weigh anything, thus it’s cheaper to ship product. Some years ago, and I’ve mentioned this before, John Ulrich and I were discussing if he should stop using the big toroidal based power supply in the Spectron amplifier in favor of a SMPS. I successfully talked him out of that possibly disastrous path. What was his reason? Sound? No. Noise level reduction? No. The reasons were cost and primarily weight. He knew it would hurt the sound but he told me his shipping cost to the Far East were very high and that was the main driving force behind the desire.

Ed Meitner tried it with the Bidat as an option. It was horrid! They dropped the SMPS option almost as quickly as they came out with it and no, I don’t care for any of the new EMM Labs gear with the SMPS. Note that when Andreas left EMM and started Playback designs he went with a linear supply.

Again, if you don’t hear the detrimental effects I hear with a SMPS that’s good for you. 

If I plug my noise sniffer in near  SMPS that thing goes off like a Geiger counter near Chernobyl, not so much with linear.

Ok, enough, I didn’t mean to hijack this and I apologize to the OP, I was just trying to answer comments that came my way. 

We return you to your normal programming :)

Switching amp (class D) and SMPS  IS the same thing.  In fact class D was discovered when engineers tried to show how responsive SMPS was by modulating it with music.  I would say that it should be more difficult to build good class D amp than good SMPS since class D amp has to maintain linearity while SMPS only keeps voltage steady.

As for the noise in amplifier - it can be easily measured.  I currently listen to music coming from my Benchmark AHB2  power amp driven by Benchmark DAC3, both powered by SMPS, and it sounds wonderful. Both received the highest Stereophile ranking in "2019 Recommended Components".

Linear power supply has to have a lot of output capacitance to keep voltage steady under the load and to filter out 120Hz ripple.   These huge, inductive capacitors are in series with the speaker (circuit closes thru them) compromising sound.  

Here is interesting FAQ: 
https://benchmarkmedia.com/blogs/application_notes/152143111-audio-myth-switching-power-supplies-are-noisy

It mentions AHB2 (powered by SMPS), perhaps the quietest power amp ever, with 132dB S/N.

I don't question your bad experience with SMPS understanding where it might be coming from, but keep your options open.  Jeff Rowland wouldn't compromise his business by completely abandoning linear supplies and making everything with SMPS if there is something inherently wrong with it.

How are the class D Amps made by down for professional applications? Any good for hifi? I’m interested in them because they’re cheap at $400 they’re not bad