With a few notable exceptions, you'd be forgiven for thinking that laptop audio circuitry is something of a manufacturing afterthought, with decisions on such things made at the very end of the design process when there's very little money left in the pot. Plugging a pair of top drawer headphones into a notebook's (often cheap and cheerful) audio out jack can therefore be a little disappointing, leading many music lovers to look to the USB ports for help. Though some USB digital-to-analog converters and headphone amps can be a good deal bigger than the laptop they're connected to, and have a suitably large price tag to match, smaller options are available. The successfully-crowdfunded ZuperDAC from Zorloo, for example, is about the size of a USB thumb drive and supports audio file resolutions right up to 24-bit/192 kHz. We've spent the last few weeks diving into our hi-res FLAC and WAV vault for some lossless easy listening.
The ZuperDAC boasts a list of specifications which should translate to a satisfying mobile music listening experience for those with an ear for high resolution audio. Signal processing is undertaken by an ES9018K2M Sabre two-channel digital-to-analog converter – which maker ESS Technology says is "targeted for audiophile-grade portable applications" – and an ES9601 Sabre headphone amplifier, which was first demonstrated at Barcelona's Mobile World Congress in 2014.
This pairing allows the 46 x 23 x 10 mm (1.8 x 0.9 x 0.39 in), 16 g (0.56 oz) unit to support digital audio with a 24-bit maximum bit depth and 192 kHz sampling frequency. By comparison, CD quality audio is 16-bit/44.1 kHz resolution and the excellent Audioquest DragonFly DAC maxes out at 24-bit/96 kHz (and also uses an ESS Sabre conversion chip).
Whether most listeners will actually be able to perceive a quality difference between a 256 kbps (or higher) MP3/AAC file, CD quality and 24-bit/192 kHz resolution audio is the subject of much emotive debate among the digital music listening community. And given the premium ticket price currently attached to hi-res WAV and FLAC files, strong critique is quite understandable.
As the old saying goes, the proof of the pudding is in the eating and should you be lucky enough to live near one of the Best Buy Magnolia centers that have recently added hi-res music stations, you can judge for yourself without spending a penny (albeit with songs that may be unfamiliar to you). If you can't hear a difference, then just stick with the format that delivers the best bang for buck quality for your ears.
Back to the ZuperDAC. There's a full-sized USB type A connector at one end of the gold or silver aluminum housing, and a 3.5 mm headphone jack and an LED status light at the other. The latter turns from red to green when the DAC/headphone amp is ready to rock. Maximum output is 25 mW per channel, there's 60 dB (L/R) channel separation, a signal-to-noise ratio of 115 dB, total harmonic distortion is given as 0.003 percent and amp output impedance is quoted at 4.7 ohms.
"We find it satisfactory to drive up to 150 ohm headphones, but beyond that the volume level may not be strong enough," Zorloo's Andy Ho said of the latter. The highest impedance headphones/earphones used during the review were 50 ohms, others ranged from 16 to 32 ohms. The ZuperDAC's amp managed to drive all without issue.
The DAC/amp is compatible with systems running recent flavors of Windows and Mac OS X, though Microsoft's operating system doesn't support USB Audio Class 2 (UAC2) on its own so users will need to download and install Zorloo's own driver. USB Audio Class 1 caters for a maximum resolution of 24-bit/96 kHz, UAC2 runs up to 24-bit/192 kHz.
The Samsung laptop used for this review runs Windows 7, and folks who have Automatic Updates turned on should have no problems with the ZuperDAC driver install. But system admins and others who prefer to install updates manually will need to ensure that the Microsoft Security Advisory that updates the system to support SHA-2 Code Signing certification is downloaded and run before installing Zorloo's driver.
Owners of a Linux-based machine will need to check USB Audio Class 2 compatibility before diving in. Mobile music lovers should be OK with iOS devices, but support in older Android devices can be a bit sketchy. Some apps, like USB Audio Player Pro, have their own driver built in and newer versions of Android also boast "out of the box" support for USB Audio.
ZuperDAC music marathon
We began our hi-res audio jaunt with a Windows laptop, running 24-bit/192 kHz FLAC and WAV files through the free Foobar2000 music player and listening with V-Moda's Crossfade M-100 headphones. The ZuperDAC consistently offered distortion-free and refreshingly clean and detailed output, with a slight widening of the stereo image for a more immersive listening experience.
We didn't detect any proprietary coloration and the frequency range appeared well represented. The only exception here was a minor relaxing of bass emphasis, resulting in usually pronounced kick and bass in fast-paced metal like Disturbed's The Vengeful One or the up front punch of Roger Waters' famous chug on Pink Floyd's Money being somewhat less powerful. It certainly wasn't enough to spoil the party, but noticeable nonetheless. On the plus side, instruments circling the lower reaches were nice and tight.
Beyond stored hard drive digital music, the larger image catered for more immersive YouTube video and Netflix movie enjoyment, and online radio and streaming services were also treated to a noticeable quality bump. And feeding an audio cable from the Zorloo device to a home hi-fi system proved a good deal richer and more engaging than simply running the cable straight from the SRS Premium Sound-enhanced audio jack.
We were offered a similar kind of listening experience while mobile with USB Audio Pro in the driving seat, RHA's excellent T20 in-ear headphones riding shotgun and the ZuperDAC connected to an Android tablet or smartphone via a USB OTG cable. There was something of a night and day difference between audio output via 3.5 mm headphone jack and the ZuperDAC here, with the music app confirming that Android was limiting hi-res playback to a max of 44.1 kHz, while the Zorloo device allowed the full 192 kHz resolution through to the earphones.
In real world terms, the higher resolution offered the instruments more room to breathe, improved placement across a wider stage and a few otherwise unheard details shone through, bringing a little more pleasure to a noisy commute or a bustling canteen area.
The ZuperDAC draws its power from the device it's plugged into. Power consumption is rated at 70 mA, and we did notice a wall outlet was needed a little more often than usual – even with the display off during continuous playback tests, our Galaxy Note 8.0's battery drained around 15 percent quicker with the ZuperDAC plugged in.
Plugging the DAC/amp into the USB port of a Macbook Pro and it just working was a real boon, and the audio output performance was as good as expected. However, we admit to only getting to listen to music files through iTunes and YouTube videos via Safari as it was a loaned Apple notebook and not one we could take control of for our hi-res pleasure.
One thing worth mentioning is heat. The ZuperDAC became quite a hot potato after being plugged into our laptop for any length of time, less so over the OTG cable to a mobile device or connected to the Macbook Pro. It wasn't too hot to handle, but you may want to exercise a little caution when removing it from the source device.
"I believe this is due to the heat dissipation at the notebook thru ground plane (which is connected to the USB chassis)," said Ho. "The ZuperDAC is a victim of the big oven."
The bottom line
Though I routinely use a desktop DAC/headphone amp when listening to audio from my workhorse Samsung laptop, its paperback novel size and use of mains power mean that it rarely gets included in travel arrangements. It's an even less appealing option for mobile gadgetry.
The ZuperDAC hardly adds any bulk or weight to a tablet or smartphone music-on-the-move setup, but allows high resolution audio lovers to grab some quality listening time while out and about, without having to haul along a dedicated hi-res player.
Zorloo's DAC/amp proved a capable beast during our review testing. There was a marked improvement to compressed audio playback compared to plugging straight into 3.5 mm audio jacks of our source devices, but the ZuperDAC's ability to play uncompressed/lossless hi-res audio files without suffering any loss of resolution was most satisfying.
The pull back at the bottom end may not appeal to every ear, but the clarity, detail and spacing make it well worth the ticket price of US$74 from Zorloo's online store (plus $5 shipping).
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