Chord Electronics Hugo TT D/A headphone amplifier

The British company Chord Electronics has always seemed to me to be audio's crazy uncle: Crazy like a fox, maybe, but definitely marching to their own tune. Their casework design often borders on the gratuitously provocative, challenging audiophiles' ideas about good taste. Yet many of my audio pals swear by the sound of Chord components, and I've heard them shine in many respectable showrooms.

The lineage of Chord's new Hugo TT DAC and headphone amplifier can be traced through several typically idiosyncratic Chord products, including the QBD76 HDSD DAC, Chordette QuteHD DAC, and Hugo portable DACs. I've noticed each of these products as, one by one, they've appeared at successive Consumer Electronics Shows—but who does any serious listening in those crowded hotel rooms? So when the Hugo TT ($4795) became available for review, I jumped at the chance to hear what crazy sounds like.

The Box
The first thing I noticed was that the Hugo TT (for Table Top, according to Chord) looks and feels like a solid chunk of metal—tapping its case at various points produced little to no resonance. Chord has cleverly designed the top and bottom halves of the case to fit together so well, the thin seam between them is barely noticeable. The TT comes in black or silver; my review sample was finished in handsome black.

The next thing I observed was how much more heavy and boxlike the Hugo TT is than many other Chord designs. The owner's manual claims that it weighs 6.6 lbs, but I'd have guessed at least 10. So I weighed it. They're right. The Hugo's smallish size (9.2" wide by 1.8" high by 8.8" deep) fools the eye.

From there things start to go crazy-uncle. Two 2"-wide depressions are cut into the otherwise rectilinear case: one in the middle of the top plate, toward the rear, and the other scalloped out of the front panel's top edge. From the bottom of the latter, a green-lettered alphanumeric display peers up like a big eye. Eight smaller divots of various sizes, all but two of them circular, are scattered across the front panel: buttons, jacks, a sensor, a switch, and a logo, all recessed. Other than the jacks on the rear panel, nothing protrudes from any part of the case, giving the Hugo a sleek, sturdy profile that, in black, looks a little mysterious.

Starting at the left of the front panel: Below the alphanumeric display are two small, shiny metal buttons, labeled IP and X-PHD, for Input and Crossfeed (more about the latter below). Then comes the remote-control sensor. At the center is the Chord logo, and below it the Power switch. To their right are three headphone jacks: a 3.5mm (1/8") at the center of a recess wide enough to accommodate a right-angle plug, followed by two ¼" jacks. All three jacks can be used simultaneously, and can handle headphones of impedances from four to several hundred ohms.

Embedded at the bottom of the scallop on the top plate is a marble of sand-blasted glass. This is your volume control, which changes color as it's rolled one way or the other: Rolling it to the right turns the volume down, and rolling it to the left turns it up. (That proved a tad counterintuitive for me: I'm used to turning a volume knob rightward to raise the volume.) The name Table Top should be taken literally: You wouldn't want to stack this DAC in a typical equipment rack unless you could clearly see and access the marble—or plan to use only the remote.

Finally, in the middle of the top plate, just in front of the volume control, is a circular cutout with a clear lens: This lets you see a bit of circuitry, as well as a series of multicolored LEDs of various function, chief among which are color-coded sampling-rate indicators. Inside the Hugo TT, red stands for 44.1kHz; as resolution increases, the LEDs progress through the color spectrum—various yellows, greens, and blues—all the way up to a neutral white glow that signifies DSD. I had a heck of a time distinguishing the green of 96kHz from the yellowish-green of 88.2kHz, but the other colors were more distinct, and were easy to match to the chart in the manual.

Powering up the Hugo TT triggered a light show of changing colors. I'm still trying to square the borderline psychedelic design of the Hugo (and many other Chord products) with the cool, level-headed demeanor of the various Chord principals I've met. So far, what I've come up with is hardly news: The British mind, like that of your crazy uncle, is a complicated thing.

Back (and side) of the Box
The Hugo TT's control layout may be crazy, but its rear panel is a return to normalcy. From left to right are jacks for: the DC power supply, left and right balanced (XLR) and unbalanced (RCA) outputs, a coaxial jack that supports sample rates up to 384kHz (BNC, convertible to standard S/PDIF RCA using an adapter, which is what I used with my Cardas S/PDIF cable), and an optical jack that supports up to 192kHz.

At the far right are two galvanically isolated USB Type B jacks, marked SD (Standard Definition) and HD (High Definition). The SD input supports up to 48kHz and requires no drivers with any source, including an iPad or iPhone. The HD jack, which I used for all of my listening, is asynchronous and employs Chord's custom digital clock. Sources supported include 384kHz PCM/DXD, as well as DSD64 and DSD128 in DoP format. The Hugo TT required no drivers to work with my Apple MacBook Pro laptop running the Roon playback software (Roon supports DSD). Although I didn't test it, Chord notes that for the HD input to work with Windows, the Hugo requires the installation of drivers from the included USB stick—after which it supports sample rates up to 384kHz.

Although use of the jacks is pretty straightforward, their labels are engraved but not painted onto the rear panel; on the black finish they're hard to read, unless you hold the Hugo at just the right angle to the light.

Finally, the Hugo TT combines a custom-made input module with the Bluetooth aptX codec for wireless capability, offering convenience at the expense of ultimate sound quality. At the midpoint of the Hugo's left side panel is a relatively large cutout in the shape of a half cylinder, encased in translucent-black plastic, in which resides the Bluetooth antenna. I tested Bluetooth operation to a distance of about 70' with an iPhone 6, and it worked great; Chord claims the range extends to 150.' Although it sounded pretty close to a CD stream, this is a compressed signal—great for parties, but not recommended for critical listening if you can add a wire.

Control the Box
In my review of Rega Research's DAC-R in the August 2015 issue, I lightly roasted the company for the DAC-R's multibutton remote control, which is useful only if you also own other Rega components. The Hugo TT's remote is also festooned with buttons you can't use unless you buy other Chord products—but at least they've included all of the DAC's essential functions: Input, Volume, Mute, and numbered shortcuts to the inputs (very handy when comparing sources).

The remote handset is made of aluminum alloy, and has little rubber feet. About the size of and heft of a solid-state drive, it's gorgeous, and comfortable to hold. As on the Hugo TT itself, each button occupies its own little recess, and requires direct aim of a fingertip: no accidental volume changes when someone sets a book on it, although firing off a command is a little tougher than with the average remote. One quirk: The Chord's Input selection was sometimes triggered by the remote for my Oppo BDP-103 universal disc player. Until I figured it out, I thought the TT had a bug that was making it randomly switch inputs.

Also worth noting: During its power-up routine, the Hugo TT can be set for variable volume output (for use as a headphone amp or preamp), or with a fixed line-level output (for use with a separate preamp). A word of caution: Selecting fixed level also sets the headphone outputs to max. Crazy! My Benchmark DAC2 HGC works similarly, but you can always visually check the position of its volume knob before plugging in. With the Hugo TT, you have to notice the volume marble's color, then remember what it means. So if you want to use the Hugo as a normal DAC with your preamp during the day, and as a headphone amp late at night, don't forget to reset the fixed volume. I speak from experience.

In the Box
There's a lot going on inside the Hugo TT, starting with the source of much of its heft: the internal battery, which is intended not for portability but for power-supply isolation. Chord warns tweakers not to replace the Hugo's wall-wart power supply, which is optimized to charge this battery: Using any other adapter will void the warranty. In fact, you can charge-up the TT and run it without the power supply, though I kept it plugged in during my tests, as Chord recommends. Battery status is indicated by a colored light—of course!—that's visible through the top panel's lens; a full charge takes about five hours.

The heart of the Hugo TT is a field-programmable gate array (FPGA) that allows engineer Rob Watts to customize most aspects of how the DAC works. I sat with Watts one afternoon as he walked me through the reasoning behind this approach, which is rooted in the idea that the mechanism of human perception of such things as soundstage depth and other psychoacoustic phenomena largely remain mysteries: Being able to tweak each parameter with an FPGA makes possible extensive listening tests, thus allowing the engineers to zero in on various desired results.

And tweak Chord does. For example, they tested various noise-shaping techniques until the measured and audible results were what they wanted. Another big part of Chord's approach is the Hugo TT's interpolation filter, which is used to re-create the missing bits between samples. Watts explained that a filter with an infinite number of taps—a digital filter that would require an infinite amount of RAM, yet would be capable of shaping a response curve with incredible "resolution" and consequent smoothness—would be ideal to perfectly re-create the original waveform. Since such precise shaping is not possible with current or foreseeable technology, Watts says he used extensive listening tests to create his Watts Transient Aligned (WTA) filter algorithm, to simulate as closely as possible the results of an infinite-tap filter.

Still, Watts says, more taps give better results with his approach, so the Hugo TT has a WTA filter with a tap length of 26,368: a number that suggests extraordinarily precise filtering. Watts showed me a chart comparing the WTA filter to a conventional filter operating on a sinewave. The difference was obvious: The WTA filter looked nice and smooth, while the conventional, off-the-shelf DAC filter produced a wave that included a series of tiny steps that Chord says can lead to such problems as high-frequency distortion and jitter sensitivity.

Chord also identifies noise-floor modulation as a factor contributing to hardness or brightness and image smear in a DAC's sound, and takes pains to clean this up with careful power-supply implementation, four-layer grounding schemes for the circuit board—and, for DSD sources and their high levels of high-frequency noise, extra digital filtering in the FPGA. Chord addresses jitter with a custom digital phase-locked loop (DPLL), also set up in the FPGA.

Listening to the Box
After fully charging its battery, I inserted the Hugo TT in my main system and fed it the S/PDIF output of my Meridian Sooloos Control 15. Initially, the Chord replaced the Rega DAC-R ($1195), which I'd just finished reviewing—and there was a subtle but noticeable improvement in detail. The Rega's sound is very slightly thick; the Chord didn't sound thick at all. A good start.

Chord Electronics Ltd.
US distributor: Bluebird Music Ltd.
275 Woodward Avenue
Buffalo, NY 14217
(416) 638-8207

edbudzil's picture

Correct me if I'm wrong, but neither your publication or your major competitor have reviewed the $2,500 Chord Hugo portable DAC. My (paranoid?) theory has been that this universally-praised component is so good, that it would have had your other portable DAC advertisers running scared. I, like many other Hugo owners, are using the device in our main system as a digital front end (in my case, connected by coax to a Rega Jupiter CD player), as well as with headphones/USB computer. While twice as expensive as my most costly purchase, the Hugo is not "twice as good", no, it's exactly what I've been looking for. The little guy squeezes the last ounce of music out of digital recordings- and, it's portable, and beats my analogue sources. Now, a day late and, for the likes of me, several $1000 short, Stereophile reviews the nearly twice as expensive Hugo TT. Chord has ("have", as the British say) just introduced the Mojo, Hugo's smaller sibling at $599. Dare you to be first to review it!

Venere 2's picture

If I read this review right, in the case of DACs, the old adage "Source first" seems to take a big hit...
It seems a DAC costing 4 times the price of another DAC, will offer noticeable, but subtle improvements. All of the DACs in this review seem close to one another (based on the reviewer's descriptions and comments).

Maybe if someone has a decent DAC, and wanted to spend a few thousand dollars to improve their system, speakers or amplification would yield better results? That is what I am getting from this review.

Jon Iverson's picture
I often struggle in reviews with how to put DAC differences in proper perspective.

Once you lock in on how a particular DAC sounds, it is easy to spot from then on (or at least a while). But I find most listeners, even a group of dedicated audiophiles, have a hard time locking in at first. But once they get it, they are pretty consistent under test.

Also, some systems make it easier to hear DAC differences than others, so would seem to reinforce your idea that speakers and amps can be a major, if not bigger, factor here.

One point though, more expensive is not always better.

bfmcosta's picture

I would be really important to say which digital filter was selected in the Auralic for the comparison, as it has 4 (for non-DSD material) that sound very differently, and the differences highlighted to the Chord Hugo TT may just reflect that...