Originally Posted by f198
Can you comment on the sound quality, it is bright or smooth? Also can you detail a little bit at why I'll want to amp with low impedance headphones ? Thank you.
Just got mine. I'm running it out a laptop (with the USB isolator, though not strictly needed) into a JDS Labs C5, terminated with a modded AKG Q701. Compared to the laptop => C5 => Q701, the HiFimeDIY U2 is pretty smooth. My first test listen is Rush's Clockwork Angels (24-bit 96 kHz). I chose it because the guitars can be pretty harsh, esp. the title track. I wouldn't say there's a loss of detail, but it's definitely easier on the ears, with more body. I've got a Rockbox'd iPod Classic that outputs 16/44.1 via line out to the C5, and while its DAC is far better than the laptop's, I doubt it can touch the HiFimeDIY U2. Haven't had a chance to compare directly. I really wanted to hear something 24/96 first
The reason I went with HiFimeDIY over JDS Labs, for whom I have nothing but respect, is that the USB receiver on the HiFimeDIY will take 24/88.2, and even with the USB isolator it was $60-$70 less expensive. Obviously the implementation is different, but on first impression I'm all smiles.
Just did another test with a troublesome track: Jethro Tull's Thick As A Brick (1997 remaster CD). The vocals are very forward in the mix and always seemed harsh, at least in one or two parts in the first 5 minutes or so. That may be a product of the remastering (loudness wars?). Now the Q701 are very detailed cans, even modded to increase/improve the low end. They tend to reveal the good and the bad. In this case, there was no sense of smoothing, at least with the vocals. Overall I'd say the DAC improved it by fleshing it out a bit more. That's all in the first few minutes. The mix becomes more balanced, and the U2 renders it well on the Q701.
Anyway, there are some anecdotal tests for you to chew on. For me, $90 very well spent. Now if I could just make it work with my Nexus 7...