Audioengine D1 32-bit Portable Headphone Amp and USB DAC AMP

DAC stands for digital-to-analog converter, a device that turns the ones and zeros of digital music into electrical signals for reproduction by amplifiers and speakers. The Audioengine D1 is an outboard DAC, i.e., a component that resides in a box outside the computer, rather than on a PCI card or on the computer's motherboard. The purpose of an outboard DAC is to bypass the computer's cheap audio circuits and process digital audio directly from USB or optical ports. The advantage of an outboard DAC vs. one on a card is that you can take it with you and it's easier to hook up gear. So does the D1 best my Mac's audio? BUILD: Out of the box my first impression was it's tiny. However, it's well made with metal case, gold plated connections and great fit and finish. Hook up was easy: a pair of RCA/TRS cables to my M-Audio BX5 D2 monitors and the included USB cable into my Cinema Display. My Mac Pro (OS 10.5) immediately recognized the new device and switched system audio to Audioengine D1. However some apps can override system audio preferences and you may have to select D1 from within the app, especially if you have multiple DAC units online. SOUND: I have tracks of me playing classical guitar, so I listened to those first since I knew exactly how they should sound. And what a disappointment: bright, harsh, random clicks and a wee bit of distortion! I was ready to return the unit but decided to read the manual: "give it 40 to 50 hours break-in before doing any critical listening." Hmm, I have other components that definitely sounded better--smoother--after a week or two or burn-in so I engaged iTunes shuffle and left the house for the day. The next day I was shocked at the improvements: smooth natural and transparent and easily besting my Mac's DAC. Incidentally, the D1 has a much hotter signal than my Mac and I had to turn down the volume to avoid burning my ears. Besting the Mac's build-in DAC was expected but a relief after the initial harsh tones at hookup. With half the burn-in period under my belt I would describe the sound as detailed and fairly smooth with no hint of harshness. And the detail is almost overwhelming: zaps, scrapes, coughs, etc., in the background of live concerts are extremely vivid whereas they were barely audible with my iPod or computer DAC. Also, the reverb tails of studio reverb are much more prominent--almost too prominent (will be going easier on the wet mix). So, yes, lots of detail you normally miss with a cheaper DAC. While that's great for a clean studio recording, it may not be so enjoyable for noisy stage and club recordings. I compared it side by side with my MOTU Ultralite ($600 recording interface) and was pleasantly surprised. I auditioned both DACs with M-Audio BX5 speakers. I can't say the D1 sounds better than the Ultralite but it's in the same ball park sonically. The Ultralite is a little more dynamic, smoother (sweeter mids) and has a flatter EQ profile whereas the D1 has a wee EQ bump in the bass and slightly more edgy treble. Both are highly revealing of background detail compared to the built-in Mac DAC. However the Ultralite has a lot more gain in the preamp section albeit the D1 is no weakling. The D1 is not ideal DAC for mixing but perfect for what I bought it for, causal listening. RFI RESISTANCE: I live in the inner city and am surrounded by cellphone and radio station transmitters. RFI is a major problem in my condo and every piece of gear needs shielding or it becomes a classic rock station. I am happy to report the D1 greeted me with complete radio silence and is well shielded. Good show Audioengine designers! IO: Digital audio may be routed to the D1 either through the USB input or the optical (SPDIF). The USB is more universal and closer at hand on most desktops. The optical input requires an expensive cable and, for me, a very long one as my Mac Pro is under the desk! Most users will be happy with the convenience of the USB hookup, and that is fine long as your audio source is 24-bit and 96KS/s or less. If you are one of the rare individuals requiring 192KS/s, you will need to use the optical input. The D1 has a good quality headphone output via a mini (3.5mm) stereo output jack. It has no problem driving my Sennheiser HD580 headphones although I mainly use it with Shure 400 series earbuds. The volume knob works fine for adjusting the volume of my M-Audio BX5 D2 monitors but a tiny twist of the knob causes volume to go from soft to painfully loud with many earbuds. Finally, I found the D1 short on outputs: a pair of RCA and a mini stereo jack and that's it. Also, it can only handle a single input source (the USB input is disabled when an optical cable is plugged in). A second USB input would have been handy for a visiting iPod or Tascam portable. GOTCHAS: There are a few minor gotchas. First, as mentioned above, finer gradations of volume control would be welcome. Also, system volume and mute controls don't work from the keyboard or Apple IR remote and must be controlled directly from the D1. Audioengine could easily write a driver to fix that if they wanted to. MOTU allows Core Audio volume control with their devices (or you can use device controls). I miss being able to mute with a simple button tap. And, finally, that bright LED light on the front panel needs a filter or disable switch (other than turning it off). LAST BLURB: A solid unit that's easy on desktop space and has great sound and sturdy construction.

I've been an audiophile for a little while, but have never really decided to start pouring money into a setup until now. I own a pair of AKG K240's and a pair of AKG K701's. K701's are notorious for being picky about their source and amp (being highly analytically reference headphones), and K240's shine for every day use, but also lack character without being properly driven. Unfortunately, since both lacked an amp for well over a year, I decided to invest in a DAC as a first step and slap on a headphone amp with it. Lucky for me, Audioengine's D1 was one of a few finds for DAC's, amongst FiiO, nuForce and HRT. I needed something that would be compact, as I wasn't ready to make a step towards a desktop DAC. As a college student, saving space is a prime requirement. After doing plenty of research, almost all of it positive for the Audioengine, I bought it and had it delivered overnight. It had an integrated headphone amp, a volume control, and was USB based. It had an optical toslink input (great for gaming consoles) and RCA output, for eventually working into a full system. I didn't think it would be this small! I was expecting something with the footprint of a 3.5" HDD, but instead it's as big as a stick of deodorant. Smaller, even. Aluminum housing with soft-touch ends, excellent RCA connections, and an amazing pot for the volume control only made it seem a lot better. The headphone jack in front is a little odd; they decided to go with the common 1/8" (3.5mm) TRS jack, instead of the more robust 1/4" (6.35mm) TRS jack. I suppose it's more accessible seeing as many people do not use 1/4" TRS jacks, except for audiophiles. The D1 being more of a compact unit, this makes sense. I suppose it's the same argument as buying a DAC at this price that has XLR connectors versus TRS. The markets just don't really coincide. But I digress. I plugged it into my laptop and it automatically initialized, installing drivers. I plugged in my K240's and was rather underwhelmed. All it really did at the time was tone down some of the sibilant highs in my electronic music. That said, it wasn't burned in. So, I left my headphones in and let it play at a moderate volume (note my K240's have seen hundreds of hours of use). Six hours of work later, I take a listen and something definitely feels different. I unplugged from the DAC and plugged into the laptop headphone jack, then back to the DAC. There it was. A remarkable tightening of the low end. When instruments couldn't be told apart, when the music felt almost hollow from the laptop, the D1 filled in that gap. Each hi-hat, each drum hit, each synth key. That hollow nature could be best described as if someone had put low pass filters on the music, like they were playing miles away. Now I am center stage. This was only with 6-10 hours of burn-in! I plugged in my K701's and also noticed a wonderful improvement in instrument separation and bass response. Music just felt richer and fuller! I then decided to plug in my 2.1 computer stereo system into it. I've owned this system for almost six years now, an old pair of Harman/Kardon satellites and a subwoofer that comes as a single system. I think it came with a Dell I had back in the day. The bass, which before, always felt just fine, tightened up a lot, and became much more focused and responsive. Tracks like Kanye's "Power" have a lot of bass, and normally played through the laptop, it was fine. Now through the D1, there's a notable increase in volume, but almost a noticeable balance between the heavy beats and the strong mids in the rhythm. Despite similar volume levels, though the D1, the floor shook! Electronic music picked up a lot more precision, and it helped reduce the harsh sibilance/treble in some of my drum & bass tracks. Electrohouse became quicker, almost. Dubstep beats no longer drained out all the mids and highs. Now I'm at 25 hours of use, continuous, too. It's not even warm. I'm very pleased to see how the D1 is responding to my collection of music, and how it seems to improve with every second. My headphones actually sound like they're worth the money I paid out for them! I've used them to great effect in games, what with every footstep clearly audible, and its placement more accurate. Now, some greivances I have: -- Because the D1 is strictly powered via USB, an adapter has to be used if you want to plug it into the wall. Besides the USB and the optical toslink ports, there's no other way to attach an input. You basically either NEED a computer or another powered source that has optical toslink. Unfortunately, you cannot just slap an auxiliary 3.5mm male to 3.5mm male between the D1 and say, your mobile phone, and expect it to play. -- You don't get a USB to AC adapter. -- No indication of what the DAC is getting as far as signal. The HRT has multiple LEDs which indicate incoming signal (sample frequency). If you're using this DAC, you better be pretty confident of the signal entering it. My grievances are rather petty, and being a compact system, my first gripe isn't really applicable. Some things to note that the D1 does: -- Increase bass response, while cleaning it up. Less boomy, rattly bass and more controlled, tighter bass which leads to a cleaner, efficient sound. -- Neutral/flat response. You don't get a really bass heavy feel nor do the mids or highs feel like they are overreaching. -- Play lossless audio PROPERLY. The stock Windows audio mixer downmixes channels before playing them, which is why it's possible to hear your Skype "new message pop" over your music while you shoot people in a game. Depending on how you set up your system, you can have all audio channels sent directly to the DAC, or if you're like me, have foobar2000 with kernel streaming play all my music directly to the D1. 24 bit, 96 khz vinyl rips never actually sounded like vinyl until today! If I ever get my hands on 24 bit, 196 khz audio, I'll need optical toslink. Remember to practice your Google-Fu and find out how to properly use your D1 instead of using it purely to convert downmixed digital audio to analog. Use it to play super-high quality FLAC's, AIFF's, and OGG's. Computer audio is rather complicated. Looking for a DAC? Look no farther. Your answer is right here.