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

I have tried a CJ PV12 (preamp) with an older class D NAD amp, but eventually removed the CJ because it imparted too much hum. Now I use a Chord DAC to drive the amp directly and it sounds good, but not nearly as good as my all tube fully balanced Cary preamp and Atamasphere amps - and I'm driving a 4 ohm speaker with a 16 ohm amp with no problems because I’m also using ZEROboxes. Recently, I added an ISOCLEAN wall outlet and power cords and I’m in heaven! I hear so much more detail and the sound is even more natural. In fact, the signal is so clean I have no overly warm tube sound at all. Amps are plugged directly into the wall and other gear is running on a standard outlet with an ISOCLEAN power strip.

Tube pre with a SS power amp is a great way to drive power hungry speakers and get that great tube midrange and high end and a solid bass.  I have a cary slp 05 and classe ca2300 driving some Thiel 3.7s.  Nice wide and deep sound stage, very natural sounding.  Not edgy or fatiguing at all.  I would recommend this combo (tube pre ss power) to any one.  Just make sure you pay attention to the output impedance of the pre and the input of your power amp.  Need to get a good match.  

^Keep an eye on the output voltage and the input sensitivity as well.

Well, I can offer an opinion of sorts. Having run all SS for years (Classe, Perreaux), eventually moving away from HiFi for a bit. Upon returning several years later, also started to experiment with adding a tube pre. First, a Quicksilver inserted with the Perreaux (not a good match), then a Bedini and finally a Levinson 23.5. I liked the sound (which is what matter, no?) I continued my quest while building my main system which now comprises an ARC LS17se and a Levinson 333 into Shahanian Hawks, the mating seem to do everything well from Rock to Jazz to classical and back to Folk.

Currently looking to upgrade the ARC to a 5se and move the 17se to my second system. So you can say I am hooked on the tube/SS combo.

I use a tube Pre (Ayon Eris) and SS Power Amp (Pass x150.8) and it sure works for me.

I note that Rogue Audio build integrateds that use tubes up front with Class D power modules - I have not heard them but they are well reviewed.