Hey - I am interested in learning about the internal workings of mic pre amps. Obviously, one of the best ways to do this is to build one from scratch. after i get comfortable, i want my final project to be a stereo pre. what kind of things really make or break a mic pre? some of the things i am thinking of adding would be a M/S decoder on one channel, DI on both inputs, switched gain (with continuous knobs for trim), obviously phantom power on both. what else would you add to a pre amp to make it stand out ?