Tubes in Hi-End Preamps

In theory you are right, the less in the signal path the better. But in practice this is not always the case. My CD player sounds much better running through my preamp than straight into my amp. With a different amp or CD player it might sound better. I think one of the most important things is system synergy. You can have two very expensive and great sounding pieces that just don't sound good together.

No audio equipment sounds perfect, no matter how high end. There is always a bit of a compromise. Some tube equipment can sound tubey and euphoric. Some SS can sound very detailed but thin and lifeless. The best stuff is somewhere near the middle of these two extremes. It is a matter of what you prefer and what sounds best to you. I own a Audio Research LS25 and I am very happy with it. It is very detailed but does not sound thin and lifeless to me. It is one of the most musical preamps I have heard. My advice would be to listen to everything you possibly can, both tube and SS and see what sounds best to you with the rest of your system.

I really like Kjweisners take on things. Another tidbit, fwiw, is that the solid state route typically is more prone to higher frequency harmonic distortion than tubes. A popular school of thought is that our ears and brains find this type of distortion more unpleasant than the higher magnitude/lower frequency distortion that has to be dealt with in tube designs. It may be that our ears interpret lower order harmonic distortion the same way they interpret delayed reflection of sound from building surfaces, and so the distortion can come across as pleasant and natural sounding, or at least not very offensive. Or maybe not. Hope you like the new pre-amp!

I own a tube and a couple of SS pre amps aswell as tube and SS power amps. Believe me when I tell you that the small voltage gain the tubes provide yield a cleaner sounding pre than the SS preamps. I have an ultramodified ARC SP6B (6 tubes) which has had every extraneous circuit disabled and it is astonishing in its purity. I have been able to change the sound to a limited degree but not its fundamental character by using different exceptional NOS tubes in tube rolling experimentation.
However as far as "tubey" goes which to me means slow and syrupy when used as a perjorative, this pre maintains a "Wire with Gain" sound. In fact I have noticed that small signal tubes actually do the opposite of that rather trite conventional wisdom. If you add tubes to a CD output stage for instance, it makes the sound generally brighter and cleaner,they actually seem to add sparkle and liveliness. This probably accounts for all the modders who know that audiophiles desire detail and purity and add small signal tubes in a previously pure SS circuit.
I think that the so called Tubey coloration you speak of occurs only with the big output tubes when used to provide big voltage gains on your power amps for instance. Even then the aforementioned expected distortion may really provide a rather extended clean sound until you push the tube to its limit then the distortion becomes quite unpleasant. This is very easy to do if you are using one of the smaller tube amps.
Therefore I can only conclude it is the circuitry that really colors the sound. I can only suggst that you rid yourself of any prejudice and see for yourself. See if you can get a couple of preamps together from the same maker one with tubes and one without and draw your own honest conclusion. I didn't want to believe it either but via extensive exposure to both types of equipment (I am part of a very active Audiophile group) and I could only draw this conclusion. Trelja was the first to point this out to me. He was right as he usually is.