I was looking for a simple, low cost solution for my desktop that would connect to a low cost pair of Dynaudio Emit M10 speakers and the DAC9/STA9 combo is doing a great job. The filter that Nuprime chose for the DAC9 really strikes a nice balance between resolution and zero listening fatigue. The unit has a somewhat clunky/cheap remote, but it's reasonably effective. I like the use of balanced connections to avoid noise as well as taking advantage of the slightly lower noise floor that those circuits offer.
 
Comparing this to my Oppo HA1, I find it more forgiving on all types of music, and compared to my Teac I find it more resolving. I'm not a huge fan of infinite volume control (volume knob doesn't have a maximum stop point), but the low volume resolution that this DAC offers supports Nuprime's claim that it's transparent at all levels. Those seeking the utmost "air" from their music but willing to risk the irritation that such ability brings to music that some recording will cause, may find this DAC somewhat boring. For music lovers seeking to listen for long periods, this setup is quite nice.
 
The DAC9 would probably get 5 stars, but it seems to need a ground lift to avoid any noise (inaudible from 3ft) at idle. I'm currently in the process of actually replacing my motherboard to determine if it is the source of the problem however (yeah, the sound means that much to me ).

Some first impressions now that I've had the HA-1 for a week.
 
It's totally natural on the my Beyer DT800/600s. The bass improved over the EMU 1616M I was using previously, which was fully expected. I probably shouldn't have been running a 600Ohm can on that interface, though it did a good job overall. Treble and mids blended well with great distinction on both cans and powered speakers.
 
Secondly, the soundstage on both the XLR outputs to my powered speakers as well as the cans had a more forward presentation. In fact, I'd say it's where it should be. The EMU really had a recessed soundstage. I like to listen nearfield, and one would think that the forward presentation puts you further into the room, but it doesn't. In fact, the stereo image is nicely presented from only 5 ft away (speakers are about that far apart as well). Vocals are clear, with no overhang or excessive warmth on male or female voices, but both acoustic and electric bass has nice weight along with excellent note delineation. Electric guitars have the rasp one would expect from their originating sound, but are not harsh. If you see or have experienced much live music in your life, you'll be impressed. Finally, I hate saying this since the description seems overused from new equipment reviews, but I really do hear more detail now than I did prior.
 
Oddly, I bought this as more of a DAC/Preamp than a headphone amp, but I believe it will cause me to rediscover my cans again. This said, it has exceeded my expectations in every aspect. I usually listen to it with the screen dimmed completely off, expecting that there may be some audible benefit, though I haven't heard a difference. I purchased the silver model because I read that the silver anodizing process produces better sound than black. LOL. Kidding of course.
 
Overall, I couldn't be happier. I can't believe what you can get for under $2k these days.

I have the 600 Ohm version of these, so other impedance models will probably vary in sound. This said, I find this to be a wonderfully balanced set. They exhibit no harshness to my ears across several genres such as Rock, Metal, Pop, Jazz Fusion, and classical. I believe the timbre of the instruments is what sets this one apart from other easy listening phones like the HD600 and 650s. You can hear the resonance of wood on strings in classical arrangements, especially quartets and such arrangements. The upright bass in several of Holly Cole's releases is clear and clean. Meanwhile, that timbre is what carries the signature of the impact from bass drums and the upright bass alike. For Rock and Metal, it conveys the dynamics and power without irritation.
 
The natural sound that these produce is preserved without the phones sounding harsh or sibilant, as many of the detail champs exhibit. To me, these are easy listening cans, which don't lose the instrumental details. Unfortunately, my only two other references are a pair of HD600s and HD650s. Those are also very easy listening, but fail to convey the timbre of instruments as well as the 880 Premiums, which is what really sets them apart. Great cans for the price.