By an amazing coincidence, I just got my Micro DAC/Amp stack today (with Desktop Module in the amp). My primary use is for the computer, which has been frustratingly under-served in the audio department. It's insane that I have all my music stored losslessly on the hard drive, but had no way of getting at it other than with Klipsch computer speakers (which are great for computer speakers, but pretty lousy on an absolute scale) and a sound card that emits a charming high-pitched tone picked up via interference from something else in the case.
My plan with the Micro stuff is to use the DAC (either via the optical out on the soundcard, if I get around to getting the cable I need for that, or via the USB that I have it set up with right now) to extract a digital signal from the computer, and then plug in either the Klipsches (for when I want to use speakers) or the Amp (when I want to use headphones).
Hooking up the DAC via USB worked seamlessly and instantly, which is nice. The sound quality is so far unimpeachable. I can't do a serious comparative review here as I've never listened to other headphone amps, but it does what it's supposed to do. The sound is crisp and clear, with no hiss other than that present in the original source material, and it's capable of driving my HD650 phones effortlessly at volumes louder than I'd want to listen.
In terms of comparisons I can make, I think that using the Micro DAC/Amp combo sounds better -- more detailed, but not in a harsh way (as if it's possible to get harsh on the HD650...), and with more controlled bass -- than the headphone out on my Parasound P/LD-2000 (an ~$1500 two-channel preamp, albeit from most of a decade ago) being driven by a Slim Devices Squeezebox, playing the same lossless files. Like most comparisons of electronics, though, it's a moderately subtle difference, not the night-and-day difference that you get with speakers or headphones; and I don't trust myself when making sighted comparisons, so take that for what it's worth.
The cross-feed is a nice fix for those studio-manipulated recordings where sounds ping-pong between channels, which have always driven me mad. But there's a noticeable change in tone (the mid-bass gets more emphasis) when the cross-feed is switched on, so for normal classical listening, I suspect I'll leave it off.
The packaging and devices are very professional and slick -- moreso than I was expecting, actually, with a well-designed, full-color printed manual and boxes with logos. (That sounds petty, I know, but I really deeply care about aesthetics. That the HeadRoom products have this elegant lightly-curved look with attractive logo and fontwork is a significant plus to me. If I were to buy something like the SuperMacro-3, I'd die a little on the inside every time I looked at it. Your obsessiveness may vary.) The build quality of the units is great, and the power supplies are far more impressive than I would have guessed -- they come with truly enormous bricks.
On the caveat side, I really wish they'd've included the appropriate cables. As it happens, I can repurpose a USB cable to connect to the DAC, and I have (bizarrely, a relic from an old sound card) a short, stout mini-to-mini plug to connect the DAC to the Amp -- but if I didn't, I'd be a bit cheesed at having to run down to Best Buy to blow $20 on stupid little cables. I can't believe it'd cost HeadRoom much of anything to throw in a few cables, and it'd make for a much more pleasant out-of-box experience than trying to rustle up the appropriate connectors.
Also on the caveat side is that hooking up my Dell DJ30 to the line-in on the Amp gives a nasty low-frequency hum and the sound doesn't really come out at all. It sounds creepily destructive, and I didn't leave it connected like that for longer than I had to. I have to believe this is Dell's fault, though, as it happens even when the player is off, and there's no such problem using either the line-out or headphone out on my wife's iRiver H340. (Any ideas on this, anyone? The Dell works wonderfully when hooked up to headphones, so why would it start making weird electrical noises when hooked up to an amp?)
