Chord Electronics Hugo DAC/Headphone amplifier

Are those people crazy?” asked a high-end audio/headphone enthusiast who had just learned the suggested retail price of Chord’s new Hugo portable DAC/headphone amplifier. “That’s an awfully steep price for a portable.”

“It’s certainly not cheap,” I agreed, “but give it a listen and see what you think.”

The skeptical young man put on the state-of-the-art Abyss planar magnetic headphones I had connected to the Hugo, picked a selection from the music library on my PC, turned up the volume on the Hugo, and then listened in rapt silence. As the track unfolded, the listener’s eyes grew progressively wider, indicating what I took to be a certain measure of disbelief. Once the track finished, the listener quietly removed the headphones, then turned to me and said, “Now I understand. The price tag gave me ‘sticker shock’ at first, but that Chord really could be considered an alternative to a high-end DAC and desktop headphone amplifier.”

Honestly, I couldn’t have put it any better than that.  When Chord’s press releases say the Hugo is the world’s first “reference-level portable,” they aren’t kidding around. In fact, as I’ll explain in this review, both the DAC and headphone amplifier sections of the Hugo sound like high quality, full-size components, which is remarkable considering the Chord is roughly the size of a small reporter’s notebook. Before we talk about the Hugo’s sound, about which there is much to say, let’s first look at how the component is configured and at the technologies that make it special.

Chord’s Hugo is a high performance portable DAC/headphone amplifier that comes with an impeccable sonic pedigree and the elegant good looks and self-evident build quality to match. The Hugo can handle almost any type of high-resolution digital audio file you’d care to throw at it, including PCM files ranging from 44.1/16 on up to 32/384 resolutions, DXD, and DSD64/128 files.

Hugo’s DAC section requires no drivers for use in Mac OS, iOS iPhone/iPad, and Android environments, but does require installation of Chord’s included ‘Hugo – Mobile DAC’ device driver for use in PC (Vista or Windows 7 and 8 environments). I did most of my review listening through a PC-based computer audio system running Windows 8 with jRiver Media Center 19 music management software and I am pleased to say Chord’s Windows driver installed and functioned with nary a glitch.

Compared to most portable DACs and even some full-sized DACs, the Hugo offers a very broad range of inputs, including an A2DP aptX Bluetooth input, a TOSLink optical input (24/192), a coaxial S/PDIF input (24/384), a driverless ‘standard’ USB input (16/48) intended primarily for use with smartphones and tablets, and an HD USB input (32/384 and DSD64/128-capable).

In sharp contrast to the overwhelming majority of DACs on the market, the Hugo does not use a standardised DAC chipset of any kind. Instead, Hugo employs a Xilinx Spartan-6 field programmable gate array (FGPA) repurposed for use as a dedicated DAC. Why would a firm choose such a counter-intuitive and unorthodox design approach? Chord’s simple answer is that it has been using FPGA-based DACs through several generations of its products and that they have consistently yielded better sound quality than conventional DAC chips do. A more nuanced answer, however, is that Chord’s FPGA-based DACs support desirable digital filtering options that conventional DACs do not.

In a position paper on DAC technology, Chord suggests that for optimal sonic results digital filters should ideally have the maximum ‘tap-lengths’ possible (arguing that, in theory, infinite tap-length filters would sound the best of all). Significantly, Hugo’s FPGA DAC provides dramatically more digital filter taps than conventional DACs do, thus giving Chord’s designers the freedom to implement more sophisticated digital filtering algorithms Chord calls its algorithm the WTA Filter, which is said to provide audibly superior handling of transient sound –especially in terms of preserving the critical timing of transient musical events.

How big are the differences between Chord’s FPGA DACs and conventional DACs? Hugo’s FPGA DAC supports 26k tap-length digital filters, whereas Chord says conventional DACs are limited to about 150 tap-length filters and claims even the largest commercial DAC chips offer “only about 250 taps.” Hugo’s Xilinx-based DAC offers far more digital filter taps than any previous Chord DAC product, which may be why Chord’s Chief Executive and Senior Designer John Franks says the Hugo is presently the most sophisticated 32-bit DAC his company produces.

Of equal importance, Hugo’s potent FPGA DAC draws very little battery power. Indeed, the big Xilinx FGPA runs on just 0.7V, thus freeing up a considerable portion of the available battery power for purposes of driving the onboard analogue audio section/headphone amplifier. Franks points out that, until this low-power Xilinx gate array became available, it would have been impossible to build a DAC of the Hugo’s sophistication in a portable format and difficult to do so even in a desktop package (because the requisite power supplies would have been huge and dauntingly heavy).  But thanks to the benefits of Moore’s Law and the march of progress, the powerful Hugo weighs in at a svelte 0.4 kg.

The Hugo’s amplifier section sports four analogue outputs: two 3.5mm headphone jacks, a 6.35mm (1/4-inch) headphone jack, and a stereo pair of variable-level RCA outputs that can, if desired, be configured to provide fixed line-level outputs when using the Hugo as a standalone DAC. While several of today’s better upper-end portable headphone amplifiers offer balanced outputs, the Hugo provides single-ended outputs only. I asked Franks about this seeming omission and he explained that, given the Hugo’s very low noise floor (roughly -140dB), its ability to swing high voltages and to deliver generous amounts of current on demand, any move to add balanced output circuitry would have increased circuit complexity and costs without offering any concomitant improvement in sound quality.

Interestingly, the Hugo offers three user-selectable levels of crossfeed filtering—filtering said to improve perceived soundstage depth and three-dimensionality for headphone listeners, at least on some recordings. The crossfeed filters can, however, be switched off for purists who prefer to listen to the stereo music signal as originally recorded. The Hugo sports simple yet effective user controls including a power on/off slide switch, pushbutton switches for input selection and crossfeed filter control settings, plus a cool, touch-sensitive, digital volume control.

The Hugo’s eye-catching industrial design features a metal enclosure finished in camera-like satin silver with one of Chord’s signature top-mounted, component-viewing ‘portholes’ positioned above the large Xilinx chip within. The Hugo provides colour-coded LEDs to denote input selection, crossfeed filter settings, the sample rates/formats of the files in play, and the volume level settings chosen. Put these factors together and you get a product that, for my tastes at least, pushes all the right ‘quality comes first’ buttons, while striking a colourful note of whimsy.

The foregoing description certainly sounds promising, but the real proof comes in the listening, which brings us to our central question. How does the Hugo sound?

All it takes is a few minutes of listening to the Hugo to recognise that it possesses that elusive ‘X’ factor, which marks the difference between very good products and truly special ones that touch on greatness. No one sonic characteristic steps to the foreground to define this product; rather, the Hugo offers the sort of across the board excellence that defies easy categorisation. However, relative to the other fine portable headphone amplifier/DACs available in today’s marketplace, the Hugo does distinguish itself in terms of its agile and muscular dynamics, the sheer vibrancy and purity of its tonal colours, and its suave, sophisticated, and oh-so-nuanced handling of complex, multi-layered tonal and textural details in the music. In all these respects, the Hugo really does sound more like a good (and I mean really good) full-size DAC or headphone amplifier – not like a portable.

To put Chord’s claim of ‘reference-level’ performance to the test, I found it instructive to compare the Hugo to my reference headphone system, which consists of the superb AURALiC VEGA Digital Audio Processor feeding the firm’s powerful and polished TAURUS Mk II headphone amplifier. For transducers, I used the Abyss AB-1266 and Audeze LCD-3 planar magnetic full-size headphones, plus a set of Ultimate Ears Personal Reference Monitors. Given that the AURALiC components together cost more than twice what the Hugo does and are thought to offer superb value for money in their own right, the bar plainly was set high for the Hugo. Even so, as you will see in a moment, the Hugo came tantalisingly close to matching the overall performance of the reference system, faring better in this comparison than any other portable amp/DAC I have previously put to the test.

In listening to the Hugo’s DAC section alongside the AURALiC VEGA, I found the two components excelled in different areas of performance. On the plus side of its ledger, the Hugo offered slightly greater mid-bass weight, warmth, and punch than the VEGA did, plus what some might regard as a smoother, more rounded, more ‘luminous,’ and thus more engaging midrange presentation. The Hugo’s mid-bass prowess came into play on any number of good pop/rock tracks featuring well-recorded electric bass guitar and drums, where the Hugo would effortlessly capture the deep, earth-shaking ‘growl’ of a Fender Jazz Bass or the rock-solid, sonorous ‘thwack’ of kick drums or large tom-toms being struck in earnest.

For an example of the Hugo’s vibrant and luminous midrange in action, try listening to Brian Chin’s heartbreakingly beautiful ‘Poesia’ for trumpet and piano from Universal Language [Origin Classical]. On that track, the Hugo shows Chin deftly exploring the expressive range of the trumpet through passages that captured the horn’s more melancholic and subdued side, but that also showed it soaring in a brilliant, gleaming, celebratory fashion. Throughout, the Hugo made the trumpet’s voice the centrepiece of the presentation, rather than allowing hi-fi pyrotechnics to steal the spotlight. The result was a trumpet sound that was glowing, golden, burnished, and natural as could be—never artificial or forced. The same was true of the piano accompaniment, where the action, textures, and timbre of the piano were plainly audible, yet never took precedence over the broader musical thread. The result, through the Hugo, was a piano sound that was remarkably lifelike, rather than coming across as a hi-fi system attempting to achieve realism.

On the other hand, I found that the Hugo offered a somewhat less transparent and less sharply defined overall sound than the VEGA, with noticeably less upper midrange and treble resolution and focus. This difference could be heard on a track such as ‘Stank’ from Jamey Haddad, Mark Sherman, and Lenny White’s Explorations in Space and Time [Chesky, Binaural+ CD], where the Hugo could almost, but not quite, match the VEGA’s exquisite handling of the subtle upper midrange and treble harmonics of the various percussion instruments in play. Similarly, it did not do quite as good a job with the high frequency reverberations and spatial cues captured in this recording. Nevertheless, the contest was quite close.

In practical terms, the Hugo handles all the high-res file formats that the VEGA can, whilst offering an A2DP aptX Bluetooth input, which the VEGA does not. The VEGA, however, offers balanced and single-ended outputs, whereas the Hugo provides single-ended outputs only. The only caveat is that, in our Hugo sample, the analogue outputs (via RCA jacks) were too closely spaced and tucked inside openings too small to accommodate high-quality single-ended cable plugs. Happily, Chord uses a local company for its high-precision casework and, just before press time, advised that it is making “some minor modification to Hugo to allow for the larger RCA plugs sometimes featured on high performance cables” (units shipping by the time you read this will have the revised case).

The Hugo’s amplifier section in many respects sounded like a ‘junior’ version of the excellent AURALiC TAURUS MkII—a comment I intend as high praise. Although the Chord offers less power in an absolute sense than the TAURUS MkII, and provides single-ended outputs only, the Hugo still shares a number of positive sonic attributes with the bigger desktop unit. In particular, both the Chord and the TAURUS MkII possess similar, Neve recording console-like voicing characteristics that consistently find that elusive sweet spot between resolution and sonic transparency on the one hand and full-bodied, soulful musicality on the other.

One crucial point to note about the Hugo amplifier is that it is so quiet and offers such a wide range of volume settings that it easily can be used with everything from super-sensitive custom-fit in-ear monitors right on up to the most power-hungry headphones you can find. Granted, some competing portables address this problem by offering switch-selectable master gain settings, but the Hugo is so very quiet that it has no need of them! With the Hugo, you just plug in your listening devices of choice (whatever they might be), set volume levels accordingly, and enjoy.

The Hugo can drive virtually any headphone you might care to use, though it is pushed near (and some might say pressed beyond) its limits when asked to drive the exceptionally power-hungry Abyss AB-1266. Normally, the Hugo did a fine job with my Abyss ‘phones, but if dynamic push comes to shove, the Hugo might conceivably run out of steam before a genuinely high-powered desktop amp would do. But with that said, note that in practice the muscular the Hugo can and does put any number of moderately powerful desktop amps to shame.

While I preferred the more sharply focused sound of my reference AURALiC headphone system to the Hugo overall, I was nevertheless impressed to hear how close the Hugo came to the reference system’s performance. When you consider that the Hugo can be had for less than half the price, and comes in a package small enough to take with you wherever you go, its appeal becomes irresistible.

I hope I have conveyed just how versatile, enjoyable, and downright exciting Chord’s Hugo is to use on a day-to-day basis. The Hugo is so cleverly conceived, so well-executed, and so well-rounded that you might find, as I have, that it becomes your ‘go-to’ headphone amplifier/DAC for all seasons and reasons. No matter where you want to listen, and no matter what types of transducers you choose to use, the Hugo has you covered. And, should you wish to use the Hugo as a high-performance, high-res DAC in a full-size high-end audio system, you will discover it acquits itself admirably in that context, too.

They say no product can hope to be all things to all people, but in the world of high-performance headphone amps and DACs, Chord’s Hugo comes a lot closer than most. If I could have one (and only one) headphone amplifier/DAC with which to satisfy all real-world use conditions and listening requirements, this would be the one I’d choose.

Technical Specifications

Type: High-resolution portable headphone amplifier/DAC.

• Digital inputs: One TOSLink optical input (24/192-capable), one coaxial S/PDIF input (24/384-capable), one driverless USB input (16/48-capable, intended for use with tablets and smartphones), and one HD USB input (32/384 and DSD128-capable, for computer playback with support from the included Chord device driver).
• Analogue outputs: Two 3.5mm headphone jacks, one 6.35mm headphone jack, one stereo analogue output via RCA jacks.
• Device drivers: Mac OS/iOS/Android – No driver required. Windows Vista/7/8 –Chord-supplied device driver required for 384kHz PCM or DSD64/128
• Digital Filters: 26K tap-length digital filters
• Controls: Input selection button, crossfeed filter network, power on/off, advanced digital volume control, with special control sequence that locks Hugo to stand line-level outputs for use as a standalone DAC.
• Battery: Sufficient power at full charge for approximately 14 hours of operation. Wall-plug power supply supplied.
• Headphone output: 110dB SPL into a 300 Ohm headphone load.
• Power Output – 1kHz 1V sinewave with both channels driven at < 0.1% distortion:
• 600 Ohms, 35mW
• 300 Ohms, 70mW
• 56 Ohms, 320mW
• 32 Ohms, 600mW
• 8 Ohms, 720mW
• Distortion – 1kHz 3V output: 0.0005% THD
• Dynamic Range: 120dB
• Output Impedance: 0.075 Ohms
• Damping Factor: >100
• Accessories: CD ROM with PC/Windows device driver software, wall-plug power supply/battery charger, a USB-A-to-USB-Mini-A digital cable, a TOSLink cable, and six O-ring straps for temporarily attaching smartphones, etc., to the Hugo.
• Dimensions (H x W x D): 20 x 100 x 132mm
• Weight: 0.4kg
• Price: £1,400

Manufacturer: Chord Electronics Ltd.
URL: www.chordelectronics.co.uk

Tel: +44 (0) 1622 721444

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