November 2014

Oppo Digital HA-1Reviewers' ChoiceLike them or not, Beats by Dr. Dre can take credit for lighting a fire under the headphone market. Manufacturers of much better headphones and associated gear are now reaping the benefits as consumers explore better alternatives. While the bulk of consumers’ attention seems to be on the portables market, the increased focus on high-performance audio has also shone a light on the burgeoning market in headphone amplifiers, and buyers are taking notice.

Right now, the hottest action in the amplification segment is in the category of headphone amp-preamplifier-DAC, with examples from Benchmark Media, Grace Design, and Antelope Audio (among others) receiving rave reviews. Charging into this space is Oppo Digital, already well known for their excellent-sounding universal disc/streaming players, with their HA-1 headphone amplifier ($1199 USD).

As usual, however, Oppo has not been content to create another me-too product. The HA-1 contains some notable differences from the rest of the herd.

Design and specs

Both the preamplifier and amplifier stages of the Oppo HA-1 are fully balanced, and the headphone amplifier stage operates in class A. A hefty power transformer, linear power regulators, and filters with custom-made capacitors ensure a clean power supply with plenty of reserve to drive all types of headphones.

The HA-1’s analog volume control is motorized, permitting both manual and remote-controlled adjustment. This can be used not only to adjust the volume through the headphone outputs, but also allows the HA-1 to function as a preamp for an audio system with speakers via its analog outputs. For its headphone output, the HA-1 has an adjustable gain setting to best match its power output to the sensitivity of the model of headphones it’s used with. A Home Theater Bypass mode defeats the volume control so that the HA-1 can be used with a home-theater preamplifier-processor or an integrated amplifier. And rather than limit the HA-1 to being a conventional headphone amp-preamp-DAC, Oppo decided to make this model Bluetooth-compatible as well, to allow streaming from and control by smartphones and tablets. This comes in handy for Internet-based streaming services and Internet Radio.

Oppo Digital HA-1

The HA-1 is handsome, with a rugged case of brushed aluminum available in silver or black. The review sample was black, which I preferred. It measures 10"W x 4.8"H x 12.2"D and weighs a hefty 13 pounds. The front panel’s large, central, color LCD display can be configured to show Status, Spectrum, or VU meters. I preferred Spectrum.

At the display’s lower right corner is an IR sensor window for the remote control. Above and to the right of this is a large volume-control knob, and below that is a USB input for Apple's iPhone, iPod, and iPad. To the left of the display, clockwise from top left, are: the power button, the Source selector, a four-pin balanced headphone output, and a 1/4” headphone jack. The Source knob can be rotated through various menus, then pushed to select the desired function.

Toward the front of the top panel is a ventilation mesh through which can be glimpsed the impressive parts crammed inside. The asynchronous USB input, based on the XMOS chipset, supports all standard PCM bit depths and sample rates up to 32-bit/384kHz, plus DSD up to DSD256. The DAC itself is the highly regarded ES9018 Sabre32 Reference DAC chipset, which has been extensively used in professional studio equipment and in many high-end consumer DACs.

Oppo Digital HA-1

At the upper left of the rear panel are the analog XLR and RCA inputs; below these are the analog XLR and RCA preamp outputs. At upper right are the digital inputs: XLR, coaxial, TosLink, and USB. At the top center of the rear panel is a screw-in Bluetooth antenna. Below and to the right of this are Trigger In and Out, and to the right of those is an AC inlet for the supplied power cord. The bottom panel has nonslip footers at all four corners.

The silver-colored metal remote control fits comfortably in the hand and can be used for power, mute, and input selection.

Oppo supplied specs for each of the HA-1’s functions: preamp, amp and DAC. Too numerous to detail here, these can be found on Oppo’s excellent website and in the downloadable owner’s manual.


After unpacking the Oppo, I connected it to my integrated amplifier via the HA-1’s analog XLR outputs, then plugged a Cardas Twinlink power cord into the AC inlet. I then screwed in the Bluetooth antenna and connected the HA-1 to my Mac Mini server with a Cardas Clear USB cable. Finally, I plugged the Cardas power cord into my power conditioner and powered up the HA-1.

Although I first read the owner’s manual, I probably could have set up the HA-1 without referring to it -- everything seemed very straightforward. I used the Source knob to choose the USB input, and selected the Spectrum display. I then launched Audio Midi on the Mac Mini, found the HA-1 as one of the choices, and selected it for the USB output.

A word of caution: Due to its class-A architecture, the HA-1 runs very hot. Give it plenty of room to breathe. Apart from that, I have to hand it to Oppo: the design and execution of the HA-1 are models of excellence.


I listened to the HA-1 three ways: as a DAC feeding my integrated amp, as a headphone amp-DAC, and as a streaming device feeding my integrated amp. Since I don’t have a standalone power amp, I couldn’t evaluate its performance as a preamp-DAC.

I began by evaluating the HA-1’s performance as a DAC. Using the Source knob, I set the HA-1 to Home Theater Bypass mode and sat down to listen. Having had a friend’s Oppo BDP-83 universal Blu-ray player in my system for a couple of months, I was familiar with Oppo’s house sound, and looked forward to hearing how the HA-1 performed.

This is one mighty fine DAC. The HA-1 functioned flawlessly, and I enjoyed many hours of fatigue-free listening with various genres of music at all resolutions, from “Red Book” 16-bit/44.1kHz all the way up to DSD.

Oppo Digital HA-1 remote

Like so many parents of young girls, over the last year my wife and I have been fed a steady diet of the Frozen soundtrack (16/44.1 AIFF, Walt Disney), which has been in near constant rotation, particularly in my wife’s car. My daughter has yet to tire of this album, especially Idina Menzel’s power anthem “Let It Go” -- and, funnily, neither have my wife or I, despite almost daily playback. I enjoy it so much that I ripped the CD to my server, but instead of listening to the songs, I’ve been listening to Christophe Beck’s orchestral score, included in the Deluxe Edition. Vuelie, a vocal performance by the male choral group Cantus, is a beautiful, goose-bump-raising piece -- it sounded absolutely gorgeous through the HA-1, the voices soaring in a resonant acoustic. The HA-1 projected a large, wraparound soundstage and cascading layers of lush sound that were positively addictive. I listened to it over and over, and even my wife didn’t complain.

Although I have three sets of Beethoven’s nine symphonies in high resolution, my favorite recordings are those of Bruno Walter conducting the Columbia Symphony Orchestra (16/44.1 AIFF, Sony Classical), remastered with Sony’s Super Bit Mapping. These “Red Book” remasterings are not only surprisingly excellent, given the more than 50 years since they were recorded, they were also masterfully performed by Walter and the musicians chosen for this studio pickup orchestra. The HA-1’s ability to render sonic textures and tonal colors was first rate, conveying all the qualities I demand for symphonic recordings: expansive soundstage width and depth, presence, harmonic content, attack, decay, and vibrato. All of this combined to relay a lifelike presentation that was among the best I’ve heard from these recordings.

With rhythmically dense music, the HA-1 was able to delineate each instrument without congestion or loss of detail. “Digging in the Dirt,” from Peter Gabriel’s Secret World Live (16/44.1 AIFF, Geffen), is much heavier and crunchier than the studio recording of this song, on Us. Despite this, the live recording didn’t sound like a jumbled mess through the HA-1, and these superimposed sonic textures added a more chaotic dimension to this track.

Having gotten a sense of the HA-1’s sound as a DAC, I switched off HT Bypass and began listening to it as a headphone amp-DAC, using my Sennheiser HD 600 headphones. Since the HD 600s are fairly easy to drive, I selected the Oppo’s Normal gain setting. I mostly use the HD 600s for listening in the early morning, when the rest of the family is still asleep, or when I want to listen to something at much louder volumes than anyone else wants to hear. Among the bands I like to listen to loudly is Van Halen. I love Van Halen -- even Van Hagar and Sans Hagar -- and the louder the better. While Eddie Van Halen is known for his pyrotechnic guitar technique, less well appreciated is that drummer Alex Van Halen and bassist Michael Anthony are one of the best rhythm sections in rock’n’roll. With “Mean Street,” from Fair Warning (24/192 AIFF, Warner Bros.), the HA-1 conveyed the drums and bass in all their skull-rattling glory -- and in “Unchained,” when they kick in after Eddie’s guitar introduction, I couldn’t help but headbang until the HD 600s flew off my head.

Oppo Digital HA-1

So, yes, the HA-1 could rock out -- but it was also very adept at highlighting more nuanced performances. Miles Davis’s Kind of Blue is often cited by reviewers, and I’m no exception. Despite the simplicity of the themes, the improvised interplay of the musicians is fantastic to hear -- it’s probably my favorite album of all time. I have stereo versions of it at 16/44.1 and 24/192, and in mono at 24/192, but my favorite is the stereo DSD (Columbia/Legacy). The HA-1 reproduced the warmth and tactility of “So What” with smooth treble and supple bass. Details such as Jimmy Cobb’s ride cymbal were noticeably crisp and clean, with a suitably metallic sheen. These were definitely qualities I could attribute to the HA-1’s class-A circuitry.

A benefit of headphones is that they can reproduce lower bass than can many expensive loudspeakers. The HA-1 was a true bass champ, effortlessly powering and exhibiting tight control over the HD 600s’ drivers. To experience this quality, I returned to Peter Gabriel -- his bassist, Tony Levin, is one of my all-time favorite bass guitarists. In the title track of Shaking the Tree: Sixteen Golden Greats (DSD, Geffen), Levin’s bass was not just suitably deep -- it was also supple, weighty, percussive, and impactful, with no evidence of bloat or overhang. I played this joyous song over and over because it was such a pleasure to hear through the HA-1 and HD 600s.

For streaming, I paired my iPad Mini to the HA-1 via Bluetooth and used Spotify, Amazon, iTunes Radio, and various radio apps downloaded from the Apple App Store. While these services don’t provide the last word in resolution, they’re still quite enjoyable for radio and for recordings that I like but wouldn’t consider buying -- you know, those guilty pleasures that I’m too embarrassed to admit I like. Although the compressed streams were comparatively flat, listening through the HA-1 was a lot of fun, regardless of format. I was able to switch on the fly from app to app with no problem. Throughout my time with the HA-1, I never had a problem with the stream dropping out, or with losing the Bluetooth connection to my iPad Mini.


While I have a headphone amp at home, a fair comparison of it and the HA-1 isn’t possible. My Ray Samuels Audio Emmeline The Predator ($475) has USB connectivity, but it’s compatible with only 16/44.1 and MP3 files. Additionally, from both technical and price standpoints, the two products are not in the same class. Needless to say, the HA-1 far outclassed the Predator in all aspects of performance, with smoother treble, tauter bass, and that gorgeous class-A midrange warmth.

For the Oppo’s performance as a DAC and streamer, fairer comparisons could be made with equipment I had on hand.

A Meitner MA-1 ($7000) has been my reference DAC for the last two years. Despite having had other DACs in my system, I’ve never felt the desire to replace the Meitner, but the HA-1 came damn close to changing my mind. If someone had snuck into my room in the middle of the night and replaced the MA-1 with the HA-1, I doubt I’d have noticed the swap until I’d glanced at the equipment rack. I had an audio buddy switch between inputs on my integrated amp while I kept my eyes closed, and I had a hard time telling which was which. Perhaps the MA-1 had a little more top-end spaciousness and a little bit more bass oomph, but I’m stretching here. That the HA-1 could hang in there with a DAC costing almost six times as much was pretty impressive.

With streaming music, it was pretty much a sonic draw between the HA-1 and my Logitech Transporter ($1999 when available). They had similar sonic qualities, but the HA-1 was more user friendly from an interface standpoint, and was more reliable at streaming than the Logitech, which occasionally drops out.


The Oppo HA-1 is a compelling product that’s easy to recommend. While I’m usually wary of multipurpose components, the HA-1 functioned beautifully in all of the roles I asked it to play in my system, and its sound quality was first rate. Its build quality is fantastic, it’s very user friendly, and it works as advertised. If you’re looking for a one-box headphone amp, preamp, and DAC, your search should begin and end here. I may not yet be quite ready to give up the Meitner MA-1 as my reference DAC, but my Logitech Transporter has just become redundant. The HA-1 is not going back to Oppo.

. . . Uday Reddy

Associated Equipment

  • Loudspeakers -- Revel Salon Ultima2, Audioengine A2
  • Integrated amplifier -- Jeff Rowland Design Group Concentra
  • Digital sources -- Apple Mac Mini running OS X 10.9.4 and JRiver Media Center 19, controlled with JRemote via iPad Mini; Meitner Audio MA-1 DAC; Devilsound USB DAC; Halide Design S/PDIF-USB interface; Logitech Transporter
  • Interconnects -- Cardas Audio Neutral Reference (XLR, RCA), Cardas Audio Clear (USB), Halide Design S/PDIF asynchronous USB Bridge (BNC)
  • Speaker cables -- Cardas Audio Neutral Reference
  • Headphone system -- Sennheiser HD&nsp;600 headphones with Cardas Audio headphone-cable upgrade, Ultimate Ears UE11 Pro, Ray Samuels Audio Emmeline The Predator headphone amplifier
  • Accessories -- Audio Power Industries Power Pack II power conditioner; Cardas Audio Twinlink and Cross power cords; Cardas Audio Signature XLR, RCA, and BNC Caps; Cardas Audio/Ayre Acoustics Irrational, But Efficacious! system-enhancement disc

Oppo HA-1 Headphone Amplifier-Preamplifier-DAC
Price: $1199 USD.
Warranty: Two years parts and labor.

Oppo Digital
2629 Terminal Blvd., Suite B
Mountain View, CA 94043
Phone: (650) 961-1118