Sony PHA-2 DAC/ Headphone Amplifier

Capable, Quiet, and Portable

Equipment report
Digital-to-analog converters,
Headphone amps and amp/DACs
Sony PHA-2
Sony PHA-2 DAC/ Headphone Amplifier

Because I could, I also compared the sound quality of the WGBH 160kbps Internet radio feed of the Hyperion Trio playing Mendelsohn’s Piano Trio Op. 49 routed from the iPhone 5 into the PHA-2 and then out to an analog input on a Wyred4Sound mPre with that same Internet radio feed also coming through my MacPro’s iTunes into the Wyred4Sound mPre DAC via its USB 2.0 connection. After matching the output levels, I found it was virtually impossible to tell a difference between the two radio feeds. Both were equally spacious, dynamic, full-range, and detailed. When the program material changed to the BSO conducted by James Levine playing Mozart’s Symphony No. 14, I was immediately aware on both sources of the slightly astringent sound of the string section and the overly reverberant recording technique.

Some prospective owners may find my main ergonomic issues with the PHA-2 are its greatest strength—its solidity and weight. The PHA-2 isn’t even close to being in the running as the most “travel-friendly” portable DAC/headphone amplifier I’ve used, weight-wise. Compared to the Resonessence Herus or AudioEngine A3, the PHA-2 is massive. When I recently attended AXPONA in Chicago I opted to carry the Astell&Kern AK100 as my primary portable audio device because of its much lighter weight and far smaller footprint. If faced with equal levels of travel-induced trauma, the PHA-2 would undoubtedly survive better than the AK100, but at the cost of its additional weight and bulk.

As consumers demand more “one-box” solutions for computer and portable-audio playback, we’re beginning to see a steady stream of new DAC/headphone-amplifier products designed for both home and travel use. The Sony PHA-2 offers a lot of capabilities and excellent sound for under $600. But since no one device can do everything, prospective owners should look at the PHA-2’s feature set carefully to ensure that it does what you need it to do. If you plan to use it with especially difficult-to-drive headphones, you should definitely audition it with those headphones before making a final purchasing decision. While the PHA-2 does drive higher-impedance headphones such as the 600-ohm version of the Beyer Dynamic DT-990 with more authority than the Astell & Kern AK100, most users are unlikely to carry this type of headphone while traveling. For those audiophiles who strongly favor a difficult-to-drive headphone, the PHA-2 will be a better option than the headphone amplifiers built into most portable devices. Also for owners of highly sensitive, custom, in-ear monitors, who are tired of listening to the low-level background hiss that emanates from many headphone amplifiers, the PHA-2’s lack of noise and hiss could make it an ideal pairing for the Westone ES5 as well as many other custom high-sensitivity in-ears.


Digital inputs: USB Micro-B input (for charging & PC), USB Mini-B input (for Walkman), USB Standard type A (for iPod/iPhone/iPad)
Recharging time: Approx. 7 hours
Outputs: Phones (stereo minijack, only 3-pole supported), Audio In/Line Out (stereo minijack, only 3-pole supported)
Analog input: One
Output power: Approx. 165mW+165mW (8-ohm, 10% distortion); approx. 90mW+90mW (32-ohm, 1% distortion); approx. 25mW+25mW (300-ohm, 10% distortion)
Input voltage: Maximum: 1V RMS
Dimensions: 2.67" x 1.14" x 5.5"
Price: $595