I've been thinking about putting together a tube preamp/solid state amp system and have run across some issues such as impedance loads and inverted polarity. What does it all mean? What kind of specs (or other #s, symbols, ratings, etc.) do I need to pay attention to to make sure the pre and amp are compatible.

Finally, and this probably should have been the first question, is it better to go all ss or all tube instead of splitting them up?

My preamps shortlist includes models from Cary, Quicksilver and VTL. The VTLs are a little pricey though (looking to stay under $1500). The Cary seems to offer the best features because it has a headphone section. None of these has a phono section which is a little disheartening. If I try to use something I already have like the phono section from an old NAD receiver or Parasound preamp, can I run it through a line input of the tube pre?

My amps shortlist - McCormack and Belles or maybe a used B&K or Aragon.

Any other suggestions?