"Don't make us come over and beat the impressions out of you. I used to be the Grand Inquisitor in the olden days. Ve have veyz ov making you talk!"
Sorry no response sooner but thought I'd let it burn in for a couple of days first. I'm not sure I'm the right person to be giving an opinion on this amp as I am new to headphone amps/headphones in general and do not have any other amps to reference it to but I do have a very good home system and can try and give an impression based on that.
First off, the thing is gorgeous and well built. Power supply is solid and weighs a few pounds and from what Antness states generates a lot of electric power, able to drive any headphone.
The sound is very open, detailed, and powerful with plenty of deep tight base. It's fast and very clear and seperates instuments and vocals well. I don't feel it colors the music at all. I have roughly a $9000 home system that I love and that gives me the sound I want which is natural, clarity, detail, speed, vocally rich and tight base without being boomy and this amp does that as well, albeit without the same soundstage that you get from listening to an amp with speakers. On the flip side, listening to a live recording of Jacqui Naylor (jazz vocals), puts you right there and you feel like you are part of her small audience, up close and personal. Drums, cymbals, horns, strings, vocals, all sound wonderfully clear, musical and detailed.
You can play it soft or extremely loud (more so than I can take) without distortion. For what its worth and my two cents, I think it's a great amp and I'm really happy with it. I'm taking it down to a local hi-fi shop on Tuesday to show the owner and compare it to a Grado amp and will check out how it does with Grado Rs 1 and 2's as well as Senn Hd 600's.
For reference, I'm using a pair of ATH-W100's as headphones. Hope that helps at least a little bit. Thanks Antness.