after listening to a couple hours, all i can say is WOW!!! the bass, treble, highs, soundstage, instrument separation are all there!! i love the four switches too. the bass boost plus high gain made my DT 880 sound more powerful and more bass impact, which i'm sure most of you that have the DT 880 know that they are bass lacking phones. i have the max out OPA 627 version. i will try to take out 1 buffer and see how it sounds like. i also have some opamps, which i will try out as well. also, some pics on the way. but for now, i am utterly impressed!! definitely worth the wait and money!