Quote: I just got the HRT today! The HRT is bigger than I was expecting - feels nice and I love that it's made in California. The HRT guys are also super helpful and eager to support their products. I haven't had a chance to listen to it yet. I will definitely compare it with my E10, and M-Stage DAC and post some impressions. Quote: Quick comparison is that Q701 is warmer/darker sounding, punchier, and has more body. Q701s have punchier bass (Q701 can actually produce deep sub-bass pretty good). AD900 is lighter, leaner and air-er sounding. AD900 has more emphasis on upper mids/highs. Q701s sound more "natural" to me. AD900s are very easily driven, but I don't find the Q701s to be as stubborn as everyone was claiming the K70x to be. Soundstage is large on both, although I find the Q's to have a taller soundstage. The Q701s sound like they have more separation, and I think this is in part because they have a less "air" (high frequencies) connecting the sounds to each other. So sounds get outlined more with greater separation and are suspended around you. I found the AD900s to be a little congested sounding in the mids : \ Maybe it's that peak at 4khz on the graph... Quote: I think the E10 is pretty impressive, and does surprisingly good job by itself with the Q701s. Even though it boosts the soundstage over my soundcard, It still can't take full advantage of the potential soundstage that the Q701s can produce. With another amp you will get more soundstage (width/depth/separation), more clarity/detail, and better dynamics - but the E10 takes you pretty far.