Tube amps have a signature sound

Hi folks, this is a bit controversial issue. We all know that nowadays none of the tube amps exhibits the "typical tube sound" (what is the typical tube sound anyway?). If someone says: tube amps have a signature sound, others would say that this signature sound is not typical to tube amps. Well, imho there is something with many tube amps (pre and poweramps). They sound quite fluid, especially in the midrange. The midrange itself is often a bit bigger and more forward than the typical solid state amplifiers. This midrange has also a certain "natural" quality (harmonic richness?). Of course there are tube amps that sound like solid state and solid state amps that sound like tube amps, but in the end I have to admit that many (or most) tube pre and poweramps have a "signature" sound that is somehow related to implementation of tubes in the circuitry. I think that this is also the reason why some manufacturers prefer tube over solid state circuitries. What do you think?

My contention here would be that the square wave, being an irritant and obnoxious to the listener, might be PERCEIVED as louder. Same reason most people would get "listener fatigue" sitting in front of a system with a lot of IM distortion. Ah- OK: "loudness cue", not actual loudness?(just re-read your post) Not that the sine wave and square wave would deflect an SPL meter to different levels at the same power, but that the square wave would be perceived to be louder? Are we saying the same thing here? I'm REALLY not intentionally being obtuse....Honest!
Rodman99999, its OK. Square waves are by definition made up exclusively of odd-ordered harmonics of the fundamental waveform (that's why they can sound so obnoxious). Maybe I should have mentioned that earlier.
That's funny: I always thought of the top and bottom of the waveform being flat as DC(simplest terms), as in while a SS amplifier is clipping. Ya learn something new every day
In defense of solid state, because somebody has to, I have yet to hear tubes recreate shimmering cymbals to my satisfaction. Also, I prefer the more stable, laid back presentation of good SS. The bass I can deal with. So, while solid state is not ideal, it has been the best compromise for myself. Admittedly, my experience with tubes has been limited and my speakers have always been relatively low impedance.
That's funny- On my system I can discern the silk of Zildjian cymbals from the brassiness of Sabians(for instance). My guess would be that you've never heard a properly tweeked tube system(could have been the cables, the tubes, the source(who knows?). How I wish I could be happy with a SS system. SO MUCH cheaper and easier to live with!!