Recently I saw an article by Rafe Arnott in Audiostream that I found interesting that listed five top-shelf (and unilaterally expensive) DACs that Rafe felt that every audiophile should hear. They are all fine examples of the performance levels that have been obtained by audio designers with unlimited budgets. That's cool, but what about the other end of the spectrum? I find it far more interesting to see what designers can do with limited budgets where they must pick and choose what can go into and around their wares. These kinds of products are vitally important because they raise the sonics of entry-level digital audiophilia for everyone.
I'm of the opinion that never before has entry-level digital been as good as it is today. And, I say this with complete seriousness, some of the current generation of under $400 DACs can sonically equal "the best" in a level-matched test in many systems. As I write this, I'm listening to a $150 DAC that I would rather be using than any DAC, regardless of price or technology, that is more than five years old.
So, what Are my own must-hear current-generation portable USB DACS?
Here we go...
Ifi xDSD - $399US MSRP
The xDSD is small and ribbed with an aluminum /magnesium chassis. Cigarette-pack sized at approximately 2 ¾" by 3 ¾" by 7/8" and weighing127 grams (.28 lbs.0 It supports resolutions up to 768/24 PCM and 512 DSD via its Burr Brown DSD1793 DAC chip. There's an analog rather than digital volume control, OV4627 ultra low noise FET input Op-Amp and W990VST digitally controlled stepped attenuator, and a built-in Lithium-polymer battery which produces 2200mAh for between six and eight hours of playing time. The IFI xDSD uses four small variable-colored LEDs on its front panel to indicate its current operating states and supports multiple input options including USB, S/PDIF Coaxial, Toslink, and Bluetooth. The xDSD had enough juice to drive difficult headphones to satisfying levels as well as sensitive ones with no hiss issues.
Grace Design Standard DAC - $150US MSRP
Although currently sold-out, the Grace Basic DAC will be back for a second round of sales soon. Just sign up for a notification via their page. I purchased mine from the first drop for $144 (the unbalanced earlier version went for $79). It is USB buss-powered and can handle PCM up to 384/32 and DSD up to 5.65MHZ. No MQA support. It is a basic DAC, meaning it has no volume control, but it does have both balanced and unbalanced analog outputs and also supports a S/PDIF digital input as well as USB (but USB or USB power adapter must be connected for power). No filter selection options or display, but the sound is seriously reference-quality.
HiDiz DH1000 - $299US MSRP
This jack-of-all trades device can serve as either an analog headphone amplifier or a USB DAC for both IOS or Android devices. It has a built-in battery and is touted as "the world's first dual balanced amplifier." With both balanced and unbalanced headphone outputs and the ability to be charged at the same time as it is playing, it boasts 122 dB SNR, 120 dB of channel separation, PCM support to 192/24 and DSD to 128x. No MQA support, but it even has its own App for playing music through your smartphone. Slightly smaller, but similar in shape to my iPhone SE, the DH-1000 is ideal for optimizing a phone-based audiophile's audio experience.
Project PreBox S2 Digital - $399US MSRP
The Pre Box S2 Digital is a DAC, digital preamplifier, and a headphone amplifier with a full-sized ¼" headphone output based around an ESS9602 chip. It features three digital inputs; coaxial SPDIF, Toslink optical, and USB B. With an ES9038Q2M DAC chip, which is based on the ES9038PRO chip, the Pre Box S2 Digital can be powered either by a USB connection or by a beefier supplied 5-volt external power supply. It supports DSD up to DSD512 (DSD over PCM) and PCM up to 768/32, as well as MQA decoding. With proprietary clock circuitry, organic polymer capacitors, and thin-film mini-MELF resistors, the Pre Box S2 Digital may be budget-priced but is not limited in features or performance. I've been using it connected to Project's Streambox (powered by the Streambox's USB connection) as a complete streaming solution.
NuForce uDAC 5 - $127.99 US
This small USB-powered DAC not only supports USB (which supplies power) but also S/PDIF. It also has a volume knob and headphone output on its front faceplate as well as a pair of analog single-ended analog outputs on the back. With an ESS sabre hyperstream DAC chip, support for 384/24 PCM and 256 DSD, 112dB SNR, but no MQA, the uDac 5 boasts good specifications and a generous feature set. Ideally suited to mate with a desktop rather than a portable (that volume control in your pocket could be an issue) this little DAC offers well above average sonics at a scene-stealing low price.