Oppo HA-2 Headphone Amp and DAC Review


Outputs3.5mm Analog
Inputs3.5mm Analog, USB A, USB MicroB
Amplifier300 mW into 16 Ohm, 220 mW into 32 Ohm, 30 mW into 300 Ohm
Review DateMarch 9, 2015

Oppo’s previous personal audio releases, the HA-1 Headphone Amp and PM-1 and PM-2 headphones, scored very well with Reference Home Theater. Now they are supplementing their personal audio lineup with the new HA-2 Portable Headphone Amp and DAC. Even with the high bar set by their headphones, the Oppo HA-2 performs even better. Packed with an ESS 9018-K2M DAC and a hybrid Class AB amplifier, the Oppo HA-2 offers up a lot of performance in a slim, elegant, well-built chassis. Plus, Oppo delivers all of this for $299.

Outputs:3.5mm Analog
Inputs:3.5mm Analog, USB A, USB MicroB
Amplifier:300 mW into 16 Ohm, 220 mW into 32 Ohm, 30 mW into 300 Ohm
Review Date:March 9, 2015
Company Website

Buy From Amazon

Why Amazon Links?

Layout and Style

The Oppo HA-2 has a sophisticated design that I didn’t appreciate until I saw it in person. Wrapped in genuine black leather, the HA-2 has a retro vibe. With the volume knob on top, which also functions as the power switch, it reminds me of old portable FM radios, but with a modern flair. The aluminum case has sleek curves and soft bevelled edges with build quality in line with Apple products. The Oppo HA-2 is about the size of an average smartphone at 2.5” x 6.2” x 0.5” and a tad heavier than most at 6.2 oz.

Three inputs make the Oppo HA-2 versatile. On top is an analog input that doubles as the line-out when used as a DAC. On the bottom are a USB A for Apple devices and a USB micro-B for Android and other smartphones with USB OTG (On-The-Go) or a computer. The HA-2 is Apple MFi Certified, ensuring proper compatibility and the ability to pass a digital signal via the Lightning to USB cable. Charging of the unit can be accomplished either via USB to computer or even faster with the included VOOC rapid charging wall plug. Output is accomplished by either the line-out or headphone out, both of which are 3.5mm mini plugs.

This slideshow requires JavaScript.

Making up the rest of the Oppo HA-2’s functionality is an input slider (A,B,C) on the bottom, a battery indicator button and meter made up of 4 green LEDs. The HA-2 also functions has a mobile power bank to charge your smartphone by holding the battery button to enable. On the side is a toggle switch for low and medium gain and a bass boost toggle. The gain control is critical to allow both sensitive in-ear monitors and larger, less efficient headphones to use the same volume control. The bass boost works in the analog domain and when turned off the HA-2 is engineered to provide flat frequency response.

Oppo includes Lightning to USB A, USB A to micro B, micro B to micro B, and 3.5 mm to 3.5 mm stereo audio cables inside the box along with a wall charger.

What makes up the HA-2?

The Oppo HA-2 uses a Class AB amplifier built using integrated circuits and hand-picked and matched discrete transistor’s at the output stage. The amplifier is rated at 300mW into 16 Ohm and that figure drops down to 30 mW into 300 Ohm loads. Before heading into the amplifier stage, digital signals get decoded by the ESS ES9018-K2M SABRE32 Reference DAC. The ES9018-K2M is a 2 channel, 32-bit digital to analog converter that uses ESS’s acclaimed 32-bit Hyperstream architecture and Time Domain Jitter Eliminator and delivers a SNR up to 127dB and a THD+N of -120dB. This chip allows the HA-2 to handle PCM signals up to 32-bit (although good luck finding anything beyond 24-bit) at 44.1 kHz to 384 kHz and DSD sample rates from 2.8224 MHz all the way to 11.2896 MHz.

The battery inside is a 3000 mAh lithium polymer type that allows for up to 13 hours of usage via analog input and 7 hours via digital USB. It utilizes Oppo’s own patented VOOC charging technology for rapid charging, allowing a quick charge to 75% in 30 minutes and a full charge in 90 minutes.

What is That? Does it Really Sound Better?

I often get asked, “Hey, what’s that?” in reference to a portable USB DAC and headphone amp and that is definitely the case with the Oppo HA-2. I also realize that answering “Its a USB DAC and portable headphone amp from Oppo” is usually met with a blank stare. To simplify things a bit, it takes a digital signal from a computer or portable device such as an iPhone or Android tablet and converts it to an analog signal. The analog signal is then amplified enough to drive a set of headphones. “But I can just plug my headphones directly into my PC and it works fine, what does spending $299 get me?”

It does work, but ever notice the background noise? Or perhaps your music starts to sound unpleasant the more volume is increased? Most computers have the cheapest parts for the audio portion and typically you get what you pay for. The USB DAC is a simple, elegant solution that can provide reference quality music playback and decode all the latest Hi-Res Audio formats.

First Set-up: iPhone -> HA-2 -> Hifiman RE600
A quality set of in-ear monitors shines with the Oppo HA-2. Setting the gain switch to low allows more precise control of the volume level when pairing with sensitive in-ear monitors. It should also be noted that volume levels can also be controlled by the device as well since Oppo utilizes the USB volume control commands to control the ESS Sabre DAC’s internal digital control. If you notice the HA-2 not outputting enough volume, be sure to check the source device’s volume setting. It’s best to leave the source volume at maximum and only control volume through the Oppo control for the highest quality.

Listening to a few tracks from Bon Iver, the Oppo HA-2 is able to resolve more detail in the vocals as well as a better soundstage than the direct headphone output of an iPhone. Another benefit to the quality hybrid Class AB amplifier is that cranking up the volume on The Black Keys makes the performance more alive. Max volume on my iPhone isn’t bad, but with the Oppo the lower distortion makes the same volume level more pleasing and less fatiguing.

Oppo HA-2 Listening SetupSecond Set-up: iPhone -> HA-2 -> Audeze LCD-X
Even with a planar magnetic headphone, the output levels are more than adequate from the Oppo HA-2 on high-gain mode. You may be thinking, “But I’m only going to be listening to a streaming service like Spotify, will this setup be too revealing?” That was my thought as well, yet in practice I find myself not at all distracted by the revealing nature of the Oppo HA-2 and a high-end pair of planar magnetics. While the combo makes the argument even stronger for lossless music codecs, I find the bit rate of premium Spotify to be enough to allow the benefits of the Oppo HA-2 to come forth.

Casual listening is improved by the Oppo HA-2, but what about serious, whisky-in-hand, dim lights, and pure focused listening? Getting the most out of the Oppo HA-2 requires a way to playback high-resolution files on a device such as the iPhone. Onkyo has released Onkyo HF Player, an app that allows Hi-Res Audio playback. One caveat: while the app is free, the high resolution feature costs $9.99.

Hi-Res Audio in WAV, FLAC or DSD formats must be transferred directly to the Onkyo HF app. This is done via iTunes or, if you have a Mac, AirDrop support has recently been added. Adding the FLAC or DSD files to the Onkyo app allows playback of those formats and supplies the Oppo HA-2 with Hi-Res Audio. Listening to a few DSD samples provided on the Oppo website, the HA-2 performs well, without any playback issues. Newer iOS devices like an iPhone 6 have enough processing power to handle these high resolution codecs, but I have read reports of older devices having problems keeping up. It is important to note this is a source issue and nothing to do with the HA-2’s abilities. The works by David Elias show excellent detail throughout the audible frequency range and the added resolution creates a convincing and tangible soundstage.

Third Set-up: PC -> HA-2 -> Burson Soloist -> Audeze LCD-X
From the brass line to the sax in “When the Saints Go Marching In” on Chesky’s Ultimate Headphone Disc, the Oppo HA-2 delivers a rich, full-bodied sound. Trombones sound wickedly rich and tangible and the binaural recording provides a wide and deep soundstage. Although the dynamic peaks of Amber Rubarth’s voice on the following track, “Don’t You”, lack the smooth, explosive, live sound that higher end desktop USB DAC’s can achieve, this little portable DAC by Oppo gets you most of the way for only $299.

Are There Any Downsides?

Honestly, not really. I was a bit annoyed when the USB connection between the HA-2 and my iPhone was lost due to inactivity. This means music plays through the iPhone’s speaker instead of through headphones. The connection can be restored by either changing inputs on the HA-2, turning the HA-2 on and off, or unplugging and replugging in the USB cable. It also lets the whole office know that you listen to Taylor Swift as it blares from your iPhone speaker.


The Oppo HA-2 Portable Headphone Amp and DAC will probably be one of the most exciting products to come out in 2015. It is incredibly well built, with a fit and finish on par with Apple products, includes one of the best DAC chips on the market, and has a quality Class AB amp capable of delivering all that Hi-Res Audio to power hungry planar magnetic headphones. It may seem odd to some that the Oppo HA-2 doesn’t store files or playback music on its own, but when you already have the music on your phone, having another portable device for that is redundant. The Oppa HA-2 has a very specific purpose, to take an existing audio source, bypass cheap circuitry, and decode and amplify the signal using high quality components, and it does this very well. The Oppo HA-2 is highly recommended by Reference Home Theater.

Review Summary
Product:Oppo HA-2
Reviewer:Stephen Hornbrook
Pros:Two gain settings to accommodate a wide range of earbuds and headphones. Plenty of power to drive popular high-end planar magnetic cans. Versatile inputs for digital connection to Android and Apple products. Brilliant sound quality from the ESS ES9018-K2M DAC.
Cons:A bit heavy. USB connection is lost after a period of inactivity.
Summary:Top of the line portable performance at a reasonable price. Well constructed and stylish to boot. The Oppo HA-2 is a clear winner.



Buy From Amazon

Why Amazon Links?

Review Summary

ProductOppo HA-2
ReviewerStephen Hornbrook
ProsTwo gain settings to accommodate a wide range of earbuds and headphones. Plenty of power to drive popular high-end planar magnetic cans. Versatile inputs for digital connection to Android and Apple products. Brilliant sound quality from the ESS ES9018-K2M DAC.
ConsA bit heavy. USB connection is lost after a period of inactivity.
SummaryTop of the line portable performance at a reasonable price. Well constructed and stylish to boot. The Oppo HA-2 is a clear winner.
Value5 / 5
Performance5 / 5
Overall5 / 5