Tube Amplifier Sound Characteristics

It surprises me that people still talk mainly in terms of tonal balance when discussing tube amps.
The warm, rolled off tube sound as it were.
Forget about it! It isn’t what you want anyway. Modern tube sound is better than that.
Tube sound is now about refinement, a sound that never fatigues or is edgy. This is the main reason I love the sound of tube amps. Too many solid state amps try to sound like tube amps by rolling off the highs and detail and do come off as slightly more refined- but boring!
Along with that refinement you get an open, clear sound and excellent transparency.
This is another reason I love the sound of modern tube amps- an open engaging neutral sound.
Last but not least the better tube amps deliver a stunningly spacious 3D sound stage. Solid state cannot touch this.
So kill the idea that the tube sound is about tonal balance, warmth and rolled off highs. That sound gets old in a hurry and it is time to be put out to pasture.  Little wonder solid state amps took off in droves.  
Tube sound is now about high end refinement, lack of any trace of harshness, leans more to a neutral beautiful open, transparent presence and midrange while presenting a spacious wide, deep and holographic sound stage.
The new tube sound should have solid state lovers coming back in droves. 

An n variable Radar chart, Just define your variables and the scales.

Ralph has it right, pick flavors your brain likes.

BTW the REF75 se is a superb amplifier, yes I have heard it length in my system….

Some very good input and some not so much. We build tube components.  Class A tube mono blocks and a hybrid tube amplifier, all point-to-point wiring.  Each has something to offer.  While the Class As are fantastic, the hybrid actually is more 3D sounding - go figure.  So some of the general characteristics mentioned are not so accurate IMO.

You need to focus on a price range and go hear a few.  Then you will get a better handle on what you prefer.

Happy Listening.      

a lot of the main points have been covered here already in the responses to the op’s post

i would add the following...

-- top tube and ss amps converging does not mean they are fully converged to sound the same
-- audio research, for the last 15-20 years at least, has tried to give users their cake and let them eat it too... meaning tubey goodness in holography and tonal accuracy and body, with extended treble and bass depth and impact of good ss...  the ref 75 is an excellent example of them largely succeeding at this endeavor for many applications
-- that said, depending on speaker load, room and volume level desired, how close a ref 75 or 110 comes to say, a top gryphon or pass or hegel in bass response, or how close those ss counterparts come to the arc tube amps in imaging and fleshed out vocals can still be quite variable