Basically this is a mini DAC for your computer with a jack for headphones. From what I've read it has a 7.8 ohm headphone output, which might be unsuitable for IEMs and some portable headphones.
I actually bought this to use for my DJ100, HD-598 and other headphones for when I can't use my main DAC and amp. I actually expected to return this or sell it immediately.
Really surprised how good it makes the HD-598 sound. Some amazing synergy there it seems like. I actually don't think it's being under-amped because in my experience the HD-598 is very easy to drive. It even gets loud enough (and still sounds good) from my Ipod Classic 3G and CD player. Best of all, the soundstage is quite large and doesn't take away from the mids and make anything sound too distant. So far I think it's fairly neutral and it doesn't seem to change any of the sound signature of my headphones. Not that I can tell..yet.
Believe it or not this actually CAN drive the HD-600 and still sound amazing. Yeah..even for me this is a surprise since I hate listening to under-amped headphones. Listened to the HD-600 for several hours yesterday with this and honestly can't hear anything missing. No Sennheiser "veil", no bloated bass, lack of bass or lack of treble. Everything sounds good. Most definitely enough volume too.
I would say this sounds better as a DAC than my Nuforce Icon Mobile (Cmedia chipset) and the Fiio E7. My HRT Music Streamer II is better in every way, but that cost me $150.
This would be perfect for those that want a simple DAC for specific headphones. I'd suggest it as a starter DAC/secondary or travel DAC. You can even put it on your keychain!
BTW I did not install any software and it works just fine! It probably even works in Linux.
It doesn't have enough power for the Q701, but still manages to sound decent. You would need to connect it to another amp for the Q701, but that should be obvious.
I haven't tried many portable headphones under 60 ohm with this yet. My DJ100 sounds fine with it, but that's a hard to drive headphone. This DAC didn't seem to cause any distortion or mess with it's signature.
Not the best sounding DAC ever, but for $40 it's hard to complain! Highly suggested for the HD-598 as a low budget DAC. You don't even need to connect an amp to it!
BTW this really does seem to bring out a ton more detail in most of my headphones. Not as much as my HRT though.
Most impressive thing is the soundstage. Seems to increase the size of it with specific music. Very similar improvements in size as my HRT, but for $40!
I also had good results with this and the KRK KNS-8400. Try this and you'll feel as if you're listening to a semi-open headphone! You'd think the signature would be all screwy, but doesn't seem to change at all.