NuForce Icon HD Silver (High Performance Headphone Amp and USB DAC)

This is exactly like the $100 more expensive Icon HDP. I'll quote the description on Nuforce's website: "The Icon HD is designed for users who want the Icon HDP's world-class USB DAC and headphone-amp performance without having a need for the Icon HDP's flexibilities" 
 
It is an HDP stripped down to a usb input, a DAC, the RCA output, the volume control, and the 6.3mm headphone output. For a person desiring only a DAC/amp for their headphones and nothing more, this is a much better deal than the HDP which might have unnecessary (depending on user) inputs and outputs and features.  
  
This is my first "real" amplifier. So, I cannot say a whole lot (please refer to the Nuforce Icon HDP reviews, as whatever is true for that is true for the HD as well, as the dac and amplifier sections on each are identical), but I can compare it to what I am used to.  
  
Using it with Denon AH-D5000 and Sennheiser HD595 headphones, it sounds fantastic. I cannot determine any flaws. As others have said, there is no noise floor and this puts out great power for a full sound (no missing bass, no muddied highs, etc). It's exactly what I would expect a hi-fi amplifier to be.  
  
Comparing it to my other amplification solutions, this thing is a giant above any of it. It beats the output on the HT Omega Claro Plus+ sound card in power, bass, and shockingly to me, even clarity - something I thought my sound card particularly excelled in. This is crystal clear compared to the Claro, which, while clear itself, just isn't quite as transparent as the Nuforce. Speaking of clarity and transparent qualities, the Icon HD completely wrecks every headphone output I've ever heard on any SOny/Pioneer/JVC/Denon stereo receiver I've owned or used. I haven't heard any super hi-fi receivers; only the more affordable ones, so the Icon's superiority is definitely expected and understandable. 
 
I think a lot of people are content with their "cheap" amplification. They just plug into their sound card, or they just jack into their home theater receiver, and they call it a day. That is what I did for the past 2 years. Today, I realize that I have been missing something that makes a huge difference. I strongly encourage anyone without discrete headphone amplification to go out and get this - at only $350, and with all of the quality of the HDP, this is a steal. 

I didn't know things could be this good. Considering the criticism of NuForce, particularly around their uDac2, I doubted if they could make something good. I plugged my AKG's into this unit and the sound was wide and brilliantly detailed. The bass was alive and fantastic. The clarity was amazing. Nothing drowned out anything else (i.e. no bass wiping its snot all over the lower mids). I couldn't believe what I was hearing.
 
I played all kinds of stuff through this. I think I actually like piano music now because of this thing. I can feal the pianist play the music, instead of just hearing the resonant timbre like I usually perceive it. Also, did you catch how the violins in U2's Bad might actually be violas and are the real deal instead of some loop like I thought they were? How 'bout the fact that Daft Punk's Recognizer from Tron Legacy actually has some studio recorded "bead shakers" and it's not 100% electronic? Everything sounds new again. Oh, and with poorly encoded music, garbage in = garbage out.
 
I can't tell you what DAC or OpAmp setup they have, but it's impressive synergy. It's the kind of thing that folks like Benchmark charge 3x for... and put it in a bigger box too. I don't talk all audiophile snobbish with subdued language. I prefer to put it out there like this: I really like it a lot.