How to match a tube preamp to a solid state amp?

I am reshaping my HT system to upgrade its 2 channel capability. The objective is to create a more lifelike reproduction of stereo and multi-channel playback from digital sources. My system, listed below, is all solid state, and lacks immediacy and soundstage. I suspect that the pre/pro is the weakest link right now, and the amp isn't top shelf either. I can only afford to upgrade one component, so I'm looking at the preamp. I also think my listening room is too small for my front speakers.

My thought is to buy a used tube preamp in the $2,500+ range and keep my AVM2 for the surround channels only. I am not knowledgeable enough to understand what potential problems could exist with such a set up, such as an impedance mismatch between the preamp and processor?

I would greatly appreciate recommendations for a tube preamp that would work well with my existing components. I may upgrade the amp in 2 years or so, but I need to select the preamp based on today's system.

I listen to vocals, jazz, pop, and movies. Music reproduction is more important to me than soundtracks. I went multi-channel on the expectation that the reproduction of SACD and DVDA would be at a higher level than 2 channel redbook, and have since learned that with my equipment, that isn't absolutely true. There's also the issue of how effectively or not the multi-track music has been mixed. I now believe that spending the same money on a dedicated 2 channel sytem would have yielded more satisfaction listening to music, but not soundtracks.

My system includes:

Aragon 8008 x5 amp
Anthem AVM2 Preamp
Teac Esoteric DV50 universal player
Talon Raven "C" front speakers
Bohlender Graebener 550 DX rear & 220 DX center hybrid ribbon speakers
HSU Research VTF2 sub

Cabling is primarily silver, and a collection of moderately priced balanced interconnects & speaker cable.

I utilize a custom TG Audio/Bybee AC filter and Porter Port receptacles into 2 20A dedicated circuits.

Room is 14 x 20 x 8, carpeted with no special acoustical treatments.

So, I can't afford a system-wide replacement and am looking for the smartest way to take a step in the right direction. HELP!