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.
distortions
There’s a huge difference between a pre-amp and a power amp.
Correct, two different active Class-D subs and one SR reciever I’ve had on my HT system, have eventually blown their smp caps, and in a chain reaction taken out the class-d amp as well, luckily new plate amps were available, and at trade price, just cost effective to repair for myself only, no way for a customer, they would maybe have been better of as Ricev’s said junking it and buying a new one.

Cheers George
I too hav3 class D A great small company in Denmark Pascal Audiomake excellen5 digital modules. I bought the Danish 
Gato Audio 400-S  then they build their own analog input output sections ,and International rectifier developed a super high speed switcch8ng for their 2 high power Mosfets my integrated sounds 
like a very sweet  SS- Tube combination . Of course I upgraded 
the fuses ,and put a very good Oyaide Sunami Power cord 
and in processs of matching the wiring throughout.
VH Audio has a Excellent Wire Thea Cotton centercore are multi Litz Small Wire awg21 solid core Upocc solid core Copper and thin porous Teflon which is the closestdielectric to air. Incredible wire, I did the whole Xover and cables ,speaker cables , now Amplifier power supply, and Loudspeaker terminals ,also
to all replace any Brass to at least high purity phosphor Brinze 
or gold over Copper RCA Connectors,IEC input ,and Speaker connectors .
Over 70 % of companies use Gold over Brass rca, IEC, and speaker terminals, Not Good but true.i sold audio for many years.. Itis a amazing upgrade  the conductivity is 3-4x  better ,which is a fact . just lookup metals resistance ,conductivity,and great wire 
throughout creates a fantastic synergy, I also use premium Xover parts  and bypsss caps, and the Zobel networks I make for the back of a Loudspeakers is simple but effective ,and cost effective.
if you or a friend is handy these are things to Strongly consider doing. You raise your systems potential at least 15% minimum is not more.

New to this site.
My first new amp in decades, bought Rogue Sphinx V1 integrated three years ago. Tube 12au7’s in pre with class D power. I bought unheard but was not disappointed. Rolled NOS Mullards into it. I think it is a good value. Doubles 100 to 200 wpc at 4 ohms. Nice phono for MM carts. Heavy transformer. Quality build.
Have added a Schiit Loki four band equalizer to play with.
Also reccently added Rogue Cronus Magnum, but that’s not a new design.
Laptop chargers, battery chargers, TV's, you name it.
-Which don't draw any more power than the Berning TF-10, FWIW. I had a USB power supply fail on me when I took it on the Grand Divide Mountain Bike Route, but that was likely due to vibration more than anything else- the Tour Divide (as its known) has a way of doing that.
You can mess up any amplifier operating class. The specific implementation is more important.
Class A implies better quality than D or inverse F, but that "class" system is not a value scale.
Class A sets the zero signal in the middle of the operating range, as to avoid the typical non-linearities at the extremes of the device's transfer curve. This was in started in the tube age. Many later semiconductor devices had poor linearity, which was "fixed" with gobs of feedback, and transistor power amplifier output stages almost exclusively have no gain, they just operate as voltage followers/current amplifiers. So linearity biasing is not the goal here, but avoiding ugly transitions when the voltage crosses the zero point. 
There would be more work getting a D amp to perform well, but of course as this thread has shown it is possible. The digitizer must be very good, operating at a high frequency and have good filters for the output. Higher frequencies will be easier to filter out and will have more resolution. 
The bit stream output from a DAC could be used to drive an output stage, perhaps skipping some time middle pieces. Change the power supply voltage and the gain changes. 
Obviously junk in the power supply will end up in your ears.