Also, just an update, I received the E9 and have it all hooked up. First impressions: I hear an improvement, it sounds clearer and seems to use more of the soundstage. But I think that's in part because it's also louder. I'm trying to get it to match the volume I was listening to without the amp.
With the amp, Windows volume should be 100% and adjustments to volume should be done using the amp's volume knob, correct?
Will be doing some more listening and post an update if any one is interested.