What class of amplifier has the most high definition sound ?

I'm pretty sure it's the tubes that do that, as it's been claimed the transformer's job is to strangle things. You have to pay attention around here.

Class D amps take some meat off of the bone. It can come off as crystal clear, defined, and completely quiet between notes (inky black) but to my ears that sound signature is the result of removing a tiny amount of the music from the source. My guess is that its a product of the output filter, a tiny amount of the good leaving with the bad.

"a tiny amount of the good leaving with the bad."

The bad being "switching frequency noise".

Trouble is, there’s still a lot of the bad left behind, with today’s Class-D topology.

Best, least coloured, fastest, cleanest, most dynamic a Class-A OTL tube amp, trouble is the speakers they love to drive are the "polar opposite" if full range 20hz-20khz.

Cheers George

Transformers provide nonlinear frequency response, not second harmonic distortion. One sucks, the other rocks. Why wouldn't you want to just connect the output devices directly to the speaker? That just sounds smart on it's face!

Ear 868 preamp,Ear 509 power or 890,.
Audio Note M5 and GamuT D 200i
Integrated: Gryphon Diablo 300, Isoteric 03/05.
Zanden.

Wrong question. It is related to results but does nor answer your question.
Operating class is not a value graduation, while applicable to RF amps not so directly with audio. All low level stages are operating in class A, i.e. full current, they only need to amplify voltage with no demamds for power. Only the output stage adds current to the formula. Here the biasing class determines the zero signal current of the output stage. Biasing needs to overcome device non-linearities at lower idle current. More current is more heat and power wasted, less for output. Heat loads increase adding demands for heat sinks and bigger power supplies.
So there are tradeoffs. 5W class A or 15W class AB?  Class D is not a biasing class, just a diffent amp architecture. Output stage is like switch mode powersupply, either fully on or off. The magic happens at the input where the switching levels are determined. Anything other than pure DC in the power supply will end up in the output just like any other amp class. 
Focusing on bias class is a waste of time. Find a good pairing with your speaker is more important. Difficult speakers will reduce the choice of amplifiers. Shun those 85dB speakers.
Good dynamics means high efficiency with budget in mind.