The Future of Audio Amplification

I have recently paired an Audio Research DS225 Class D amplifier with an Audio Research tube preamplifier (SP8 mkii). I cannot believe how wonderful and lifelike my music sounds. The DS225 replaced an Audio Research SD135 Class AB amplifier. Perhaps the SD135 is just not as good as some of the better quality amps that are out there, but it got me thinking that amazingly wonderful sonance can be achieved with a tubed pre and Class D amp. I have a hunch that as more people experience this combination, it will likely catch on and become the future path of many, if not most audiophile systems. It is interesting that Audio Research has been at the forefront of this development.
Good quality Class D is the practical ticket these days (efficient and sound great done well) if your speakers require lots of power and current to do their best and you care about higher SPLS.

The only equivalent alternative is a more traditional giant, bulky, expensive power-sucking monster amp of yore which are becoming increasingly hard to find and afford because frankly hardly anyone wants to have to deal with all that.

The other popular and unique use case for Class D is you just want something very inexpensive and small that represents a very practical and good value. That can be had for <$100 and matched to the right also inexpensive but good quality small speakers can get you a significant portion of the way there for practically nothing on the high end audiophile scale of things.

That is very bad news unfortunately for high end audio! Perhaps one reason for some of the derision heaved towards Class D in some cases.

If your speakers have limited bass extension, or are just an easy load to drive, and perhaps are somewhat more efficient, or you just do not listen at higher SPLs, then any good quality more modest power amp design might do.

Great topic BTW! Amp technology HAS come a log way in recent years and continues to evolve and getting the right amp for ones needs and speakers is one of the most critical decisions to be made towards the goal of getting the best sound possible at a particular price point.  Class D is a game changer for sure!
I recently heard the Julian Lage trio at the Berklee Performance Center from a 5th row center section aisle seat. A Class D 8 boxes per side "Phased array" above me...sounded great. I did a show with his trio a couple of years ago using a Class A/B system...he sounded great there also. I’ve heard recordings of his trio through my Class A single ended 12WPC tube amp, and clearly, small wattage little hand wired tube amps are the future, and the past...or something. Tonight I’ll be at the last show of a John Scofield stand at "Scullers" (off the Mass pike), they use what I assume are Class D phased array speakers, and he’s promoting his new thing, "66." Feel free to say hello, assuming you can get through my bodyguards.
It’s interesting, folks have been pairing tube preamps with solid state amps since the 1960s, and often liking the results.

Personally I prefer the sound of a solid state preamp with a tube power amp to the other way around.
Tube preamp, tube power amp, tube guitar amps, tube paper towel innards, if innards is what those are called.