Who tried Class D only to return to S/S or Tube

Excellent idea for a balanced thread George... I have happily gone back and forth from class A/B to D over the years. In chronological order, here are my amps since 1998....

Rowland M7 -- An uber-currented class A/B mono released around 1987 with a golden sound.

Rowland M312 class D stereo -- My first venture into class D.... Much more nimble and present than M7. Is both more linear, and has greater exposure of harmonics.... Beutiful transparency, and sweeter than M7, although it does not have the euphonic midrange glow of M7. Yes, overall, I much prefered it to M7.

Rowland M625 (V1 (early production actually) class A/B stereo -- Harmonically just a little denser than M312, but did not have the same amazing transparency between notes that M312 had. But the main issue with it was that it was not quite powerful enough for my Vienna Die Muzik... As a result, during fff passages or loud transients, it gave me the impression that it was "working for living". I heard later production units at RMAF, and they were quite superior to my early unit.

Rowland M725 monos class A/B -- These guys had all the power I needed, and had several circuit and materials enhancements that made them really wonderful amps... Yes, I did prefer them over M312.

Rowland M925 monos class D -- My current amps. These are uber amps that use NCore NC1200 modules buried in the output stage. By far the sweetest and most musical amps I have ever owned, as well as the most powerful and resolving ever to be in my system.

What's my future... Not sure yet. I suspect that for my next amp, I might want to simplify a bit.... One option might be to go to the class D Rowland Daemon superintegrated, which will also serve as DAC. The other possibility is to keep my Aeris DAC, and to adopt the new M625 S2 stereo, which instead runs in class A/B. Not sure in which direction to go... I probably will want to listen to the two contenders before making an eventual decision. I have heard from people in the know that the class A/B M625 S2 might be the finest amp that Rowland has designed... But I have also heard that the class D Daemon makes wonderful music in its own right. I am a pragmatist... There is marvellous music and sound possible with any clas of amps. Final decision will be determined by audible satisfaction, and... Budget.

Saluti, G.

Excellent post as usual Guido.
I'm another who has been in and out of class D for the past 7 or 8 years. My first foray was with the inexpensive PS Audio Trio A-100. This little amp blew me away with it's small size, no heat, and most of all relaxed and engaging sound. How much of this positive impression was based on the excitement of the new product is a question I still ask myself.
I liked the amp so much I bought another and used them to bi-amp. After a few months though, I couldn't say I preferred bi-amping to a single amp.
Without going into the different types of modules used in the different amps, I'll just say the Trio A-100 did not use what were considered "audiophile" quality modules. As that was the case I went searching for better class D.
There were several attempts at bettering the little PS Audio amp without success until I bought a Bel Canto Ref 500S amp. This amp seemed like the absolute "straight wire with gain" amp, in other words, perfect sound. Should'a quit then? Not on your life.
As like most of us, I had several amps to switch in and out just for the heck of it and to keep audio boredom at bay. Mostly standard class A/B amps; none of which were better than the Ref S500, only different. One day, on a whim I placed $100 ebay bid on an old Harman Kardon PA2200 amp. As luck would have it, I won the bud and a few days later I hooked this amp in to my system. Was it better than 20 times more expensive Bel Canto? No. But there was something about this amp I really liked. It stayed in my system for about a month and I couldn't find reason to remove it.
I did remove it to recap the amp and do some rewiring. I also adjusted the DC balance and bias on the amp. After all my fiddling the amp still sounded wonderful. I sold the Bel Canto.
A few years and many amps later, (including a few tube trials) I wanted something very compact for my system. I ended up with a Wyred4Sound mAMP mono blocks. This amp uses the same module as the Bel Canto I found perfect so I figured it would be perfect for me. I found a good deal an a pair and hooked them up. Clean, quiet, perfect(?), but somehow lifeless. Unfortunate as they really fit my space perfectly.
I'm now using an Aura Vita integrated amp as it also fits (barely) my space. I think I'm done trying the class D thing. Although I understand the allure, I also understand, it's not to my taste. And that's really what it's about.

I owned Gilmore Raven stereo amp for a few years, then upgraded to the Raptor monoblocks. Was happy with them for several years as well.

Then I built a pair of two stage, direct-coupled SET monoblocks, with 6E5P driver and 833C power tubes, producing 200wpc. These are so much better from bass through treble that I was stunned. More real-sounding, more musical, and more authoritative. They make me want to listen to music as often as possible. I'll not go back.

Oh, and prior to the Gilmore Class D amps I owned Flying Mole Class D monos. The Gilmores were better than those, but the FMs were still nice sounding. I also auditioned NuForce Ref9 SE monos and thought they sounded awful - harsh and screeching are the descriptors that come to mind.

I don't see myself with anything but my 833 SET amps from now until I will them to my son.