Three Miniature Portable USB DACs

Have DAC, Will Travel

Equipment report
Digital-to-analog converters
Cambridge Audio DacMagic XS,
Hegel Music Systems Super DAC,
Resonessence Labs Herus
Three Miniature Portable USB DACs

For audiophiles who travel a portable DAC has become one of those “must-have” travel accessories, right up there with a toothbrush and an unexpired credit card. The first generation of portable USB DACs was big and had limited high-resolution capabilities in comparison to the current crop. But as technology marches forward, more capabilities and smaller footprints abound. I’ll look at three small USB DACs in this review—Cambridge Audio’s DacMagic XS, the Hegel Super, and the Resonessence Labs Herus.

Cambridge Audio DacMagic XS
About the size of a small box of wooden matches, the Cambridge DacMagic XS is one of the smallest and lightest portable DACs I’ve seen. It measures approximately 2 1/8" by 1 1/8" by 3/8" and weighs under 4 ounces. On one end you’ll find a micro-USB input and on the other end a 3.5mm stereo output. The top of the DacMagic XS has its own analog volume control, which “fully bypasses the soundcard and volume control of your computer.” The two large buttons, plus and minus, are easy to locate and use even in dark or cramped spaces. Instead of plastic, the DacMagic XS is housed in a beveled brushed-aluminum case that should be capable of surviving a high level of abuse. The DacMagic XS has a small LED next to the headphone jack that glows purple or blue when the unit is operating properly and red when you try to boost the volume past its maximum level.

Inside the Cambridge Audio DacMagic XS you’ll find an ESS 9023 24-bit DAC chip that supports PCM bit-rates up to 192/24 from a USB 2.0 input. Straight out of the box the DacMagic XS is set up as a USB 1.0 device, which will only support a maximum bit rate of 96/24. Switching over to USB 2.0 requires holding down both the + and – buttons for at least five seconds until the small light in the DacMagic XS flashes three times. Once in class 2.0 the DacMagic XS will remain a 2.0 device unless you switch it back.

The most difficult part of using the DacMagic XS with a Mac computer is finding the right kind of connector to attach it to the Mac. The DacMagic comes with a six-inch cable, but if you need a longer one, which I suspect many prospective owners will, the DacMagic XS shares the same type of micro-USB connection as the Astell&Kern AK100, AK120, and AK240. A&K (and others) sell micro-USB cables on its site.

After attaching the DacMagic XS to one of my Macs (I tried it with a MacPro desktop, MacPro portable, and a Mac Mini), the AMSCP (Audio Midi Setup Control Panel) on each Mac recognized the DacMagic XS immediately. Once the DacMagic XS was set for USB 2.0 operation the AMSCP showed that it was capable of handling up to 192/24 files.

The only ergonomic quirk I experienced while using the DacMagic XS was that it was sensitive to static electrical shocks. All it took was a couple of strides across my office and back, then touching the DacMagic to generate enough of a static shock to disconnect the DacMagic from the USB buss—it would vanish from the list of DAC options in AMSCP. To correct the problem I needed to disconnect and reconnect the DacMagic XS from its USB connection, at which point it reappeared on the AMSCP DAC list and began playing as if nothing had happened.

DacMagic XS’s Sonic Sorcery
I’ve seen the question posed on multiple locations on the Web, “Are thumb-drive-sized DACs a real sonic upgrade or merely convenience devices for accessing higher-definition music files?” In the case of the DacMagic XS the answer is clearly, “Both.”

Since most prospective purchasers will want to use the DacMagic XS with headphones, I used a wide variety of different headphones and in-ear monitors with the DacMagic XS. With the most sensitive in-ears, such as the Westone ES-5 custom in-ear monitors (115dB sensitivity), the DacMagic XS did generate some low-level hiss and background noise. With somewhat less sensitive in-ears, such as the Ultimate Ears In-Ear Reference Monitors, the DacMagic XS was quiet enough that the music came from a virtually silent background.

The DacMagic XS’s headphone amplifier section had adequate gain and power to drive the Audeze LCD-2 and Mr. Speakers Alpha Dog headphones to satisfying volume levels with good bass extension. I was quite impressed by the combination of the DacMagic XS and the Grado RS-1 headphones, which can be quirky with portable gear. The bass sounded especially potent in this combination. I also enjoyed the venerable AKG K701 headphones connected to the DacMagic XS. While offering more of a left-brained rendition of music than that of the Grados, the AKGs connected to the DacMagic had well-controlled upper frequencies that still had air and extension.

When connected to my desktop computer-audio system the DacMagic XS did a fine job of creating a believable three-dimensional soundstage that had all the weight, size, and imaging specificity of a “full-sized” DAC. When set to maximum output the DacMagic XS had enough gain to allow it be used like a fixed-output DAC into an analog preamp. While not quite as transparent and revealing as my reference DACs, including the April Music Eximus DP-1 or the latest version of the Wyred4Sound DAC2 DSD SE, the DacMagic did pass enough musical information to be completely involving. I never felt during my time with the DacMagic that it was limiting fidelity to the point of “grayness,” which is the way some “entry-level” portable DACs sound.