Excuse me. Do you know if i use the preamp output to a external power amp for speakers, Will i obtain the same warm tonality?

You would, and how much "warmth" is going to depend in part on your choice of preamp or driver tube. Still Valhalla is one of the more drier tubes I've heard so I can't say if it'll meet your expectation of "warm"

Schiit's Lyr 3 is more of what can be widely accepted as "warm" in terms of tonality

Interesting. "Warmth/Warm" is very subjetive adjetive. Then, let me remake my question. About the "body" of the sound. For you, Valhalla 2 add more body to the sound in bass, mid and high region of frequencies? I pretend to use this Valhalla 2 like "the preamp" before to my power amp of my towers (loudspeakers).