I got this card recently for my media PC to use it for the optical output, but damn, the thing is very good. I mean, I've got plenty of other much more expensive DAC's, and I've used the Essence ST in my main PC for a long time, but to be honest, I think D1 is virtually indistinguishable from it in terms of sound. Even though it doesn't have a headphone amplifier per se, just a line out, it can power the Beyerdynamic T1's very well. They get as loud as on the ST with the middle gain setting, the bass is just as deep, tight and punchy as on the ST, which is usually the thing that gives out first when it comes to underpowering the T1's. On 70-80% of volume, they're on a perfectly loud listening level (that's with levels in the Asus driver panel set to 76%).
I tried it in my main PC for some gaming, and it's equally impressive, Battlefield 4 sounds absolutely every bit as good as on the ST, maybe a hair thinner and less weighty, but hey, for $70 this is one hell of a sound card. I've never even expected it to sound any good, just bought it because it was the cheapest card with an optical output, I didn't mean to use it as a sound card at all and didn't expect it to sound very good, let alone have power to make T1's sound really decent without having them lose any of their essential characteristics.
I can recommend the card. As someone who's had the D2, ST and STX, and knowing how great the value for money is with those cards, the D1 takes it up to another level in those terms. I honestly think that sonically it is as good as Nuforce HDP or the Musical Fidelity V-DACII....it certainly beats them in terms of measurements.
One odd thing though....the higher the impedance of headphones, the louder they get on the D1, total opposite of any other source I have. For example, HD650's and T1's go louder than let's say DT770 80 ohm, or especially the K701's (which really don't work well at all out of it). Not to say low impedance headphones don't work properly, they do. My favorite combo with it is the Sennheiser HD380Pro, it's a very nice pairing, with D1 being ever so slightly bright, and HD380 being slightly warm and sometimes a bit too lush.
Edited by derbigpr - 5/18/14 at 7:25am