If I'm looking for "Tube Sound", why would I put a Tube Pre in front of a SS amp?

I’m with minorl on that.

Enthusiasts will obsess over whatever aspect they choose but the more I listen the more I tend to think people’s expectations and preferences are what matter most. That and the ability to assemble a system that works well for them accordingly.

Its not that hard or expensive to make great sounding music at home these days, at least on a smaller scale, as long as one knows what they want and how to achieve it.

Oh and most importantly have realistic expectations for example expect that all recordings sound different and no system will ever make them all sound top notch or any particular one the way you might prefer it would sound. Well maybe with enough digital processing in the mix if one really must make things sound the way they want them to rather than the way they are.

Now to do the same on a larger more realistic scale, that is harder. But it also can be done with either tubes or SS or a combo of the two, again as long as one has the know how needed to achieve it with a modest budget. The biggest challenge there is that the trend is for speakers to keep getting smaller and more expensive which makes it harder to achieve realistic sound levels with low distortion especially in larger rooms. Use of powered subwoofers can help more than ever there though.

Atmasphere I cannot explain why but I have also found good modern Class D amplifiers to not be "irritating" as well as some of the others you identify.

I’ve owned and heard some other SS amps as well that qualify.

Maybe the non irritating amp club has some other perhaps more anonymous or lesser known members these days?

Pass and Curl may be the trailblazers but it seems others have practically followed in their path in one way or another.

Nobody wants to buy an irritating amp that I know of so designers who do would have to be considered lacking if others have proven it possible. I’d hire someone else to design my amps for me if my guy did not do things "right".

Whatever the technical details my ears clearly tell me tube amps do not have the good sound market cornered these days even if perhaps that was true to a greater extent in the not so recent past.

Atmasphere I have ARC tube pre-amp and Bel Canto ref1000m amps in my main system and newer BelCanto c5i digital Class D integrated amp in my second. They each sound quite different. The c5i in particular is smooth as silk with no edge or irritation whatsoever even when used with my Dynaudio monitors which can have a bit of a natural edge to them. The only fault I can find with it is the 60 watts do well but only go so far. It’s a fabulous device in a small reasonably affordable package overall.  Also has phono and serves well as a headphone amp with similar qualities. 

Atmasphere my ARC is SP16,  not latest but newer.   

It has its own flavor of sound like any piece does.    Dry is not an adjective that comes to mind with it.  

The sound is hard to distinguish as "tube" based I would say, which I like.   I do not have enough data points to say exactly how it would compare to others but the results of using it in my system are quite good I would say and not leaving me cold having heard many a top notch system including a few incorporating Atmasphere amps. 

Each really good system I hear sounds different but all share certain attributes including the ability to go loud and clear without listener fatigue during longer listening sessions.  

I run 3 good quality speakers in three different rooms off the system with the ARC.   The sound in  each case varies widely.   With either of my OHm Walsh speakers there is no edge whatsoever which lends itself towards very long enjoyable listening sessions.   With my Dyunaudios in a smaller room, there is more bite to the sound which makes things more exciting perhaps but some might find it harder on the ears over time.

It all depends.  Good sound is a team sport that includes not only all the technology playing together but the room and the listener so its always hard to predict outcomes.