Summary: The Audioengine D1 has great design and build quality, and the audio is really good. I'm using it with the USB connection (haven't tried the optical input yet), Windows 7 laptop, and Bose AE 2 headphones. Most of my music files are variable bit rate mp3 with a high of 328k to a low of 128k. The audio preformance has the warmth of a tube amp with the detail and clairty of a solidstate amp. I'm really like it, highly recommend.
Summary: I packed the D1 on my summer trip and have it hooked up to a Mac Air and Bose Soundlink Bluetooth speaker. It sounds great! I was able to easily compare it with a Bluetooth and 3.5mm cable hook-up and it's quite noticeable. There is ample bass and the midrange is clearer. If you care at all about sound quality, the D1 is a pretty inexpensive way to improve your tunes.
Pros: Good build and comes with the 3.5 mm audio cable.
Cons: Have grippy or suction style feet so unit can stay in place.
Summary: I would recommend this to people who are considering portable DAC, including NuForce. I ordered the open box and it came in excellent condition. No scratch, no dent, no sign of use. However, the USB cable that it came with does not work. The computer cannot detect it and I could not hear any sound. So I read their troubleshooting section and switched the cable. It worked immediately! One thing I like the most about this DAC is its optical input.
Summary: I have this hooked up to Audioengine 5+ speakers to my computer. the sound is awesome coming through these speakers. Installation was very easy..Im using Sony v6 headphones clean sound tight bass.
Summary: I must say the reviews I had read here on Crutchfield and elsewhere were right on. The Audioengine D1 makes a big difference in listening to music from my computer. It's not earth shattering, it's subtle but definitive. I'm using the D1 paired to an Audio-Technica ATH-M50. At first listen I noticed bass did not sound boomy as it did before (not the headphone's fault), even from a poor youtube source of the Harlem Shake.
Pros: Better controlled bass Cleaner vocals Makes instruments more discernible
Summary: I'm using the D1 with the PSB Alpha PS1 amplified speakers - and it is a great pairing (my PC is a home build, core i7-870, Win-7 64b w/ 16GB ram). Clean, accurate sound from my mp3's (I also have WAV files and itunes AAC as well). I use a belkin gold series 6 foot usb cable to connect with my computer, which works well (10 ft did not work for me). Setup was easy, once I switched to the 6ft cable. Windows easily recognizes the D1 and auto installs drivers.
Pros: Build quality, excellent sound. USB powered. Large volume control knob on front of unit. Good warranty.
Cons: A tad pricey... quality 10 foot USB cable to computer did not work w/ the D1 - presumably due to USB power requirement (6 foot worked fine -thankfully - since 2-3 foot was NOT going to cut it for my setup)
Summary: I researched a lot to pick the perfect DAC/AMP for work. I have the headphones on all day and the sound from the PC just wasn't good enough. I bought better headphones that helped a little but still it was not rich and full. I talked to Derrick at Crutchfield and he recommended the Audioengine D1 over the other model I was considering. I ordered it and it arrived well-packed and quickly. Installation was a snap.
Pros: Super easy to install, great music quality, good build quality, easy to use volume control knob.