The Oppo HA-1 is a harvester of many tricks, so many in fact that it is almost unfair to label it strictly a headphone amplifier as the acronym in the name suggests. It really stretches the boundaries of inputs, outputs and digital conversion all within a reasonable amount of desktop real estate.
As with all things Oppo, attention to detail appears to be a top priority, even down to the packaging. In a market where the focus on sound quality can allow manufacturers to slip by with off-the-shelf interfaces and external design, the Oppo ship is watertight. In rare form for most HiFi equipment, the head amp includes a fully interactive graphical interface, complete with pretty icons for source selection. Connectivity is king with the HA-1. Nearly every single base is covered. In the rear you can find super DSD-friendly USB, single ended ins and outs, balanced XLR ins and outs, and one of each type of available digital input (including optical, coaxial and AES/EBU). To top it all off Oppo included both an in and out trigger and Bluetooth connectivity with aptX. An external remote is included, but in case you don’t want another one lying around the house, Oppo even has a remote app for your perusing pleasure that connects via Bluetooth. [PRBREAK][/PRBREAK]
The front panel has a standard ¼ inch headphone jack, 4 pin balanced XLR for headphone and USB input for iDevices. It’s practically a new gold standard for headphone amps that has yet to see an equal. In truth, Oppo could have likely gotten away without the head amp section and charged the same, if it weren’t for its highly regarded BDP-105 Blu-Ray player whose feature set and price overlap with the HA-1. If we were to look at the HA-1 through a lens of personal audio the only thing that is missing is a dedicated 3.5mm headphone jack for IEMs, like the one found on the new WA7d by Woo audio. While running the amp through the paces the ¼ inch jack did display just a very slight hum through the ultra sensitive JH Audio JH16s (the 16s do come in lower than the recommended impedance of 32-600 ohms for the amp). The upswing is that volume control was delightfully distributed, even for IEMs (allowing for a nice gradual increase that peaked around 11 o’clock) and the hum wasn’t really audible at all while music was playing. All in all the HA-1 still gets the check box approval for IEMs. Simply tapping into the USB Apple connection on the front panel with the JH16s noticeably cleaned up the sound when compared to the plugging directly into an "old" 6th gen iPod Nano’s headphone output. The rated output impedance for the class A amplifier is an impressive 0.5 Ohm and 0.7 Ohm for both the balanced and SE connections respectively.
The 4.3 inch display screen features color, but is not touch sensitive. The menu is easily navigated via push-capable source selector knob. Simply rotating the knob brings up the previously mentioned "pretty" icons indicating the source, of which there is an applause-worthy eight in total. Pushing deeper into the menu allows you to pick from three pre selected home screen display setups, two of which animate while music is played through the device. The "VU meter" option pays a little homage to the McIntosh look, while the "Spectrum" home screen makes for a pretty fun, visual frequency representation. Like the BDP-105, the 13 lbs. HA-1 is very heavy for its size. Fit and finish is simply outstanding and puts many higher priced audio products to shame. The connectors in the back feel very secure against the back panel and do not wiggle or feel loose when applying cabling. The box itself has a nice shape to it and even though it is a bit deep, most users should be able to find enough space for it on a standard sized desktop. Some of that extra weight no doubt is a contribution from the toroidal power supply. From the Oppo website: "A toroidal power transformer offers superior power efficiency and much lower exterior magnetic fields over traditional laminated steel core transformers. The HA-1's toroidal linear power supply provides a very clean and robust power source to the audio components." Even though it may be inconsequential to some audiophiles, its worth mentioning that the power cable that comes with amp is one of the beefiest I’ve ever seen packaged with a piece of audio equipment, a fine testament to Oppo’s value proposition. The volume control knob offers up a fair resistance when turned and feels solid to the touch. While the on board screen suggests a digital volume control with another pretty animated graphic, Jason Liao from Oppo cleared the air with regards to the potentiometer. "The volume control in the HA-1 is purely analog. One of the design goals of the HA-1 is to keep the signal in analog domain once it leaves the DAC. Since the HA-1 is a fully balanced design, we use a 6-gang precision potentiometer part for the volume control. Each left and right channel is controlled by 2 gangs of the potentiometer. We use the fifth gang for sampling the position of the knob so we can display the approximate volume level on the LCD screen. The potentiometer has a motor-driven mechanism so it can be remotely controlled via IR remote or Bluetooth app. A nice feature of the motorized volume knob is that when you change the amplifier’s setting from NORMAL gain to HIGH gain, the HA-1 will mute the audio, turn the volume knob to reduce it to a safe level, and then un-mute. This can greatly reduce the surprise when someone changes to HIGH gain and gets a loud sound."
Among the many inputs of the HA-1 lies another interesting add on for a head amp, Bluetooth. The tech requires the addition of included external antenna, but the small piece barely peeks out from behind the amp and extends the range to an admirable distance. The application is threefold. Pair with a computer or smartphone as a source, pair with a Bluetooth-capable headphone as an output and pair with a phone/tablet as a remote control. The HA-1’s Bluetooth is 2.1 +EDR and supports both the SBC and buzz worthy aptX audio transmission formats. Switching between the über resolution of the USB connection and Bluetooth revealed an unsurprising slight loss of dimensionality, but was still surprisingly adequate for a quick connection from a mobile source in a pinch. The coinciding "HA-1 Control" app for smartphones provided a pretty seamless extension onto the OS. Volume control, input selection, mute and up/down track selection all worked without a hitch, but the BT connection did suffer a small quirk. Bluetooth connectivity is powered off when the head amp is powered down so you can turn off the HA-1 from a phone, but not on. The app makes you aware of this by closing down completely after tapping the orange power button from within the software. You need to manually turn on the amp before restarting the application. Overall the user experience with the app is straightforward and practical. The volume control physically rotates the knob on the unit and even displays the current dB level remotely.
The main silicone pushing conversion duty is the popular ESS SABRE 9018. The digital section of the HA-1 operates like a 9018 with proper implantation, which is to say it sounds pretty darn spectacular. The overall effect is pleasantly transparent, especially considering the going price for the amplifier. Plenty of top end air, excellent extension on both ends and a fine, crisp resolution mark just some excellent highlights of the "ESS patented 32-bit Hyperstream™ DAC architecture and Time Domain Jitter Eliminator" ES9018 implementation in the Oppo. The included asynchronous USB connectivity is now becoming a bit of a standard feature for almost any up-to-date DAC, but DSD compliance isn’t quite there yet. The HA-1 does allow for playback of DSD64, DSD128 and even DSD256 if you happen to cross paths with a file that requires it. There is perhaps a slight edge to the sonic retrieval, favoring detail over organic delivery, which became more apparent when comparing to the higher priced Auralic VEGA. For nearly 3Xs the price and sans head amp, the VEGA was able to add a subtle layer of naturalness to the equation, but the much of same coveted ES9018 house sound could be found in the HA-1. As the Oppo DAC was put through the paces, it was increasingly impressive how well it scaled up to the occasion. Dedicated amplifiers like the Questyle CMA 800R and Auralic Taurus really swung out under the influence of both the SE and balanced output feeds. The soundstage from the DSD version of Norah Jones Turn Me On makes for a fairly impressive headphone demo. The organ sound through the HA-1’s balanced outputs was so spicy it almost felt like you could reach out and wave your fingers though the fluttering sonic tapestry it painted. The front and center vocals appear with plenty of virtual air and space to separate them from the rest of the well-placed instruments. The tonal sum here still nods in the direction of BDP-105’s composure but is housed in a much smaller suitcase.
Most of the critical listening of the headphone amplifier section of the HA-1 was done through the 4 pin balanced headphone output on the low gain setting. The headphone sample used included both Oppo’s matching PM-1 planar magnetic headphone and the Audeze LCD-3 as a reference. Balanced output from end-to-end was definitely top of mind when the HA-1 was designed. "The internal analog audio signal path of the HA-1 is fully balanced. For digital audio, the signal runs in balanced mode all the way from the DAC to the output jacks. Balanced analog input is kept intact, and single-ended input is converted to balanced at the input buffer. All single-ended outputs are derived from the balanced signal as well. The balanced design provides better common-mode noise rejection and improves signal quality. The balanced headphone output provides twice the voltage and four times the power of the single-ended output, enabling the HA-1 to drive the most power hungry headphones. It also provides better channel separation by eliminating the common ground return path." There is a timbre richness to overarching sonic texture that accompanies the amplification stage. Samples cut from the balanced line outs confirms it existence, but also reaffirms that its impact is only slight. While this sonic affluence may be polarizing for some, those with a taste for texture will find the signature right at home. The response remains strongly linear, focused and very easy to listen to. Dynamic response, low-end impact/extension hit hard and fast like a well-oiled solid-state amp should.
Oppo makes it easy to see why the HA-1 is so much more than just a simple headphone amplifier (although it can be easily isolated and utilized via the SE and balanced inputs). With both single ended and balanced outputs in addition to a wide cross section of source capabilities it is a virtual Swiss army knife of head amps. Perhaps one of the overlooked extensions of this metaphor sits quietly under the volume knob. The USB iDevice connection really brought out the best from iPods with a deliberate and discernible improvement. Jam packed with features, the HA-1 holds a nearly endless supply of applications to improve your desktop listening.
From a straightforward up-to-date techs-and-specs position the Oppo is currently unchallenged at its price point. It is a features-driven product with spectacular results. It is so much more than a headphone amplifier in the same fashion that an Oppo player is so much more than just a Blu Ray transport. Innovation, durability, flexibility and enough connectivity specs to make your head spin give this little contender both its charm and its value. Its on hand compatibility paired with a sleek digital side makes it one of the most complimentary components for desktop listening in the sub $2000 range.
- Product - Oppo HA-1 Headphone Amp & DAC
- Price - $1,199
- Product Page - Link
Source: MacBook Air
DAC: Auralic Vega
Amplifier: The Calyx Integrated
Loudspeakers: Zu Soul MkII
About The Author
I’m a recovering musician turned audio reviewer. I currently manage and write reviews for Audio-Head.com and freelance with several other publications. I love tech and the tools of music, especially the ones involved in reproduction. After I finished my undergrad degree in business I went to the local community college and got one in photography, which was way more fun. I like it when people have unbridled enthusiasm for something and I have the utmost respect for individuals who try to create, even more for those who are good at it.