Why some preamps does not play music? Cold?

P.S. Guys, this is pure technical question. I'm not asking which preamp does it all, so please no preamp recommendations!!! I just want to understand what is causing said phenomena, that is it.
Thank you for understanding.

The reason a preamp may or may not be emotionally involving has usually to do with distortion. I'm not talking about a lot here either. Just a small amount of higher ordered harmonic distortion that is difficult to measure is easily heard by the human ear as brightness.

This is because the human ear/brain system converts all forms of distortion into some sort of tonality. Higher ordered harmonics are an excellent example- and have a further complication with the human ear as the ear uses those harmonics to gauge how loud a sound is. So when they get messed with, the ear hears it as louder, harsher and brighter.

Music is processed in the limbic centers of the brain. However, if the brain detects that there is something wrong somewhere, it has a tipping point wherein the music processing is transferred from the limbic centers to the cerebral cortex (where consciousness/intellect resides).

When this happens, the emotional connection is lost. No more foot tapping, none of that feeling of wanting to dance.

So what the designer of the electronics has to be aware of is what forms of distortion to which the brain is most sensitive, and avoid them through design. This is not really that hard if you understand engineering, what is hard is that you have to know the engineering and the physiology at the same time.

One example of a design technique that causes a loss of emotional impact is the use of loop feedback in the circuit. Loop feedback, while overall suppressing distortion to a great degree, actually **adds** higher ordered harmonics to the signal. You already know the effect of that. But it does more- there are usually intermodulations at the point that the feedback is applied (the feedback node). These intermodulations may not have any musical relationship to the signal at all, at being at a low level, exist more as part of the noise floor of the preamp or amp. This has been known for the better part of 60 years (see Norman Crowhurst- he was writing about this in the 1950s).

Now it happens that the ear has a masking principle- wherein the presence of a louder sound will mask the presence of a quieter sound (this is the basis of the encoding of mp3 files BTW). This is well-known. What is less well known is that there is an exception to the masking rule that has to do with hiss. This is likely evolutionary as wind and water make hissing sounds in the natural environment, and the inability to hear noises below the hiss might have profound survival aspects!

So we can hear about 10-20 db into a natural hiss noise floor (the exact amount being a matter of the individual and also debate, but the 10db figure seems to be a solid). Now if the noise floor of the circuit is composed of harmonic and inharmonic (intermodulation) noise (as opposed to the hiss that arises from noise sources in the circuit unrelated to loop feedback), the result is that even though consciously we can't hear a lot of difference between the two noise floors, the unconscious portion of our brain (which is about 95% of the brain structure) can detect that something is wrong. 

When it does so, music processing is transfered to the cerebral cortex: the emotion connection is lost.

Does that help with the understanding? Any questions?

I, like Ralph, was going to cite distortion as the main culprit. I learned something new about how the brain processes music - limbic center vs. cerebral cortex. Thanks!
Biasing the transistor or tube correctly is key to getting the correct sonics from the preamp. When switched on, the unit it cold & the bias is quite a bit off + it's still drifting. As the electronics warms up the bias establishes itself at the design point & also stabilizes i.e. stops drifting. This takes anywhere from 30-60 mins; sometimes/often more. For example, Wadia claims that their CDP sounds best after 72 hrs of continuous on. I can attest to this. After 72 hrs the entire tank-like unit is warm to the touch (vs. stone cold when 1st switched on).
Tube amps too - most manuf say to not bother checking bias voltages for atleast 30 mins after turning unit on. Same deal with s.s. units. 
Besides stabilization of bias voltages & currents the 2nd aspect would be what the actual bias voltage & current is as set by the designer. Is the tube being run "low & hard" i.e. low bias voltage, high current OR the opposite - "high & soft" i.e. higher bias voltage, lower current. The bias point will tell in which region the device is operating in terms of output distortion, output impedance, gain, output noise. And, this will affect the sonics. Of course, there is no way to know this by simply popping off the top lid & peeking inside. A tete-a-tete conversation with the designer will reveal this info (& many manuf are cagey to reveal this proprietary info for a good reason). There are plenty of 6922 & 12AX7 tubes in the market but some preamps using them sound really good & others so blah...
A 3rd possible reason is the quality of surrounding components - the resistors, signal capacitors, power supply capacitors, diode bridge rectifier, bypass caps, power supply snubber caps, grounding scheme, seperation of power supplies of the noisy output stage vs. the quieter input stage & the output impedance as higher output impedance has an interaction with the interconnect cable parasitic R, L, C + an interaction with the proceeding stage's input impedance that will affect sonics. For example, at one point a friend & I were messing around with a s.s. power amp's bridge rectifier circuit, power supply & bypass caps. Using a certain type of rectifier diodes + power supply caps + power supply bypass caps made the bass sound muddy compared to removing the bypass caps & using an even faster recovery Hexfred recitifier diode. 
All of these items affect sonics.... 

Atmasphere - thanks Ralph for one of the most succinct and cogent pieces of writing on acoustic engineering design I've read, someone should cut it out and save it for all future similar queries 😺

I appreciate the answers, didn’t even bargain for that deep level of technicality and psychiatry.))) I was hoping somebody just to say "go ahead re-solder this capacitor and everything will be OK". - that level of technicality) However, I’m afraid I didn’t express myself clearly enough and thereby mislead the public here). I have five preamps, but said issue persist only in one out of five. This one (tube pre), INHO is, the best (out of five) sounding preamp in terms of extensions, transparency, clarity etc. "Foot tapping" is also non-issue, i.e. plenty of that. However, as it most apparent on complex, avangarde jazz pieces (Kith Jarett, Jan Garbarek, Chick Corea etc.) it looses musical connection (?) It does it on any kind of music, but on regular music it is less obvious, because it still have enough "melody (?)" left to connect sounds into music(?). When switched to any other, out of 5 preamps, (cold, SS or whatever) which BTW, have less of extensions, clarity etc.,, the music comes back. So, the correct word is probably musicality not emotional engagement? I don’t really believe (for whatever it worth))) that any distortion has anything to do with this issue, cause like i said other preamps most likely have more distortions been not as clear and transparent as the one at issue.Just wanted to clarify the issue, to bring everybody onto the same page.

phd: "Some preamps are more accurate then musical, maybe that’s the case here." Sounds more like it.