Tube sound is not about warmth. It's about correct presentation.

@asctim “…good tube amps sound plain and natural, not exciting or magical.”

Let me change the gist of that a little. By being natural… and musical, they capture the magic of the music. I absolutely find good tube amps magical… they can send shivers down my back and goose bumps on my arms… it is the reality of the music, so exquisitely reproduced. Anyway… that is what I am talking about… nothing plain.

In other words, good tube amp just sounds right, the way it should be. And that's kind of magic, yes.

I have only owned two tubed components.  One was a Prima Luna integrated amp, and I hated it and returned it.  It sonically was the equivalent of pouring maple syrup over a steak.

  However, my favorite preamp for the past several years is Cary Audio SLP3.  This broadened the sound stage and fully fleshed out instrumental colors with sweetening everything 

"Tubular" Dudes

The surfers nailed it years ago

And above I wasn't being entirely facetious. The perceived "liquidity" of tubes is a certain something hard to technologically dissect apparently.

“Surfing to me is like playing music. You play different melodies with different boards.” – Skip Frye