Headphone Reviews

Performance
Features
Ergonomics
Value

AT A GLANCE
Plus
HDMI input for high-res music on Blu-ray
Adjustable ’phone impedance and sampling rate
Sounds good with different ’phones
Minus
None to speak of...

THE VERDICT
Essence’s HDACC bridges the gap between Blu-ray music content and legacy audio systems with an extremely adjustable and great-sounding DAC.

The most unusual product in this roundup is the HDACC HD Audio Center from Essence Electrostatic, a company that also markets flat-diaphragm loudspeakers. Like the NAD, it qualifies as a headphone amp, DAC, and stereo preamp with TosLink, coax, and analog inputs. But its greater claim to fame is a pair of HDMI jacks, input and output, on the back panel.

Why add HDMI to what Essence refers to as a digital preamp? The company wants to unleash the high-res audio content found on Blu-ray Discs and make it playable on pre-HDMI preamps or receivers. The HDACC accepts the HDMI input from a Blu-ray player, decodes the uncompressed PCM audio from the disc’s lossless soundtracks, and feeds it to your audio system via its analog or digital outputs; the HDMI out can pass video to your display. Along with the HDMI jacks, the back panel offers a USB jack, analog XLR stereo outputs, and various ins and outs (one of each for coaxial, optical, and analog RCA). The front panel’s quarter-inch headphone jack is the only full-size headphone jack among these three products (the others use minijacks). An analog minijack input patches in mobile devices and converts their analog output to digital before upsampling it for playback. I contented myself with testing the USB (computer) and HDMI (Blu-ray player) input.

The unit is a breeze to operate, thanks to a clickstopped volume knob that’s easy to twirl with fingers or even just flick with a thumb. I used it with pleasure. Power and mute buttons are on the top edge. Essence provides a mini-remote that handles power, volume, mute, input select, and menu navigation. Even if you lose the remote, the volume knob can be spun to cycle through menu items and pressed to select the desired one.

Burrow into the menu to select headphone impedance of 16, 32, 64, 200, 300, or 600 ohms. You may also elect to set resampling on the ESS Sabre DAC to six rates from 44.4 to 192 kHz or just bypass sample-rate conversion altogether; the HDACC provides explicit sample-rate information on its display. The headphone and line outputs can be fixed or variable.

Running warm but not alarmingly so, the HDACC aced the USB demos. It had even more top-end control than the NAD, but not at the expense of detail. Tracks that sometimes drove the Sony ’phones into the discomfort zone with other amps—the Beethoven strings, the Scriabin piano trills, Jimmy Page’s wah-wah guitar—remained civilized with the HDACC. George Harrison’s sitar on “Norwegian Wood” was memorably tangy via the Sony and even tangier via the Sennheiser. With the Sennheiser and Audeze, the HDACC reconciled all the disparate elements in the Bob Marley track—the echo-enhanced lead vocal, loping bass, and grooving, chiming percussion, as well as the sweet vocal embel- lishments of the I-Threes—into a unified and natural vibe that must have been what the artist intended.

In the final act, I moved the HDACC to my main system to test its HDMI input with my Oppo BDP-83 Blu-ray player. The two pieces of music that came in for closer scrutiny on Blu-ray Disc were Led Zeppelin’s Celebration Day and Carlos Kleiber’s recording of Beethoven’s Fifth. Be warned that these might have been apples-and-oranges comparisons. For Zep, I was comparing a Blu-ray Disc’s decoded DTS-HD Master Audio soundtrack with a CD-ripped ALAC file. For Beethoven, I was comparing a “Pure Audio” Blu-ray Disc’s decoded Dolby TrueHD soundtrack at 96/24 with a FLAC download at 88.2/24. The mastering jobs may have also differed, as they did on “No Quarter” when Jimmy Page’s guitar, immovable in the ALAC file’s right channel, briefly panned from right to center to follow camera moves in the Blu-ray concert video.

Whatever the cause—be it the DAC or the content—the final Zep demo was the best of all, with refinement and ease that spread across the three headphones. Somehow this combination of hardware and software narrowed the performance gap between the Sony and the more expensive Sennheiser and Audeze. (This might come as an unpleasant surprise for those who have paid $1,699 for the Audeze, only to see the $400 Sennheiser and $110 Sony holding their own, though the full potential of the Audeze may have been unrealized. Whether it would prosper more with an amp or DAC closer to its own price tag is a question I’ll address in a future review.)

On Pure Audio Blu-ray, the Beethoven track continued the train of thought, delivering orchestral immersion through all three headphones. The Sony’s presentation was still ever so slightly more forward than that of the others, but it became sweet and euphonic, while the other two sacrificed a little instrumental detail for a more spacious concert-hall ambience, with more emphasis on reflected sound. I could close my eyes and imagine myself in the recording venue, Vienna’s Musik- verein. No, it wasn’t a perfect reproduction of that gilded jewel box, but it meshed with my golden memory of the real thing.

The Essence HDACC is everything a good headphone amp and DAC should be, and then some. The addition of HDMI may be transformative for those looking for a way to get high-res Blu-ray soundtracks into a legacy system. But don’t ignore its other talents. It’s the only headphone amp in this roundup to offer selectable impedance matching, and the only DAC with selectable sample-rate conversion and bypass. It also performs admirably with a variety of headphones.

Read the full story, "Supercharge Your Headphones: 3 DAC/Headphone Amps Put to the Test" here