What do I need to know to make sure a pre amp is compatible with an amp? I'm looking to buy my first set of seperates and I would like to know if all pre's will work with all amps? What kind of specs do I need to know so that they will work properly together (electronically speaking)? This will be for two channel only. I'm currently looking at used McCormack DNA 1 or DNA 0.5, with the TLC-1 pre, or some used Audio Research (SS) gear, but am not limited to this gear. I have Dynaudio 1.3mkII speakers, if that helps... Any help would be greatly appreciated! Thanks!