An amplifier shouldn't "sound" like anything - the best possible amplifier would be a wire with gain. Tube amps do have their own sound, primarily due to higher harmonic distortion and the use of output transformers in the signal pasth. Whether this "sound" is agreeable to you varies by the individual, but there is certainly no universal agreement that a tube amplifier sounds "best".
I have built multiple amps of different types and topologies. Each one of them 'sounds' completely different. This is the reality of amplification. There is no perfect distortionless amp at all frequencies for all speakers. The interactions between the circuit and the impedance presented across all audible frequencies by any random speaker are infinitely variable. The sound of an amp is the combination of all factors in the system, which includes physical interactions and their response to the variations in presented impedance.
So yes, an amplifier shouldn't sound like anything, but they always do in reality. Within that reality, we can make judgments about the general qualities of certain types of amplifiers. If you want to comment on my question please do. Otherwise, kindly go away, and keep your comments about your magical fairy tail land where all amplifiers are perfect to yourself.
What sounds neutral also seems to be highly subjective.
I think "colour" of sound is a fitting analogy though - in the same way that our can eyes adjust to color temperature within a certain range i've noticed on the scale of hours/days I can become accustomed to speakers/amps with quite different frequency responses.
