If I'm looking for "Tube Sound", why would I put a Tube Pre in front of a SS amp?

@unsound yes in my experience and that excludes speakers just talking electronics. Speakers obviously have the greatest effect of all.

The right tube preamp such as Thoress  will give more depth and a warmer sound.

Most people I heard of drive electrostatics with tube amps. Preamp is not the most important component. Only tube power amp gives real taste of tube sound.

@inna I have run tubes for quite a long time and I will have to totally disagree with you there. Nothing changed the character of my sound more than a good tubed preamp.

Another rationale for using a tubed preamp is that tubes work better than solid-state in amplifying voltages since tubes work at hundreds of volts while SS works at tens of volts.  Solid-state work better at amplifying current since they have much lower output impedances, so there is a good reason to use SS power amps.  Not sure which will have the greatest "tube" sound since that is more subjective and affected by so many factors.