Sony PHA-1A Review – Portable High-Resolution DAC and Headphone Amplifier

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Sony PHA-1A is no longer available – see other alternatives: iFi Audio Nano iDSD

If Sony engineers hadn’t invented the Walkman player long ago, the portable audio market probably wouldn’t exist today. However, Sony’s contribution is not limited to the inventions of 40 years ago. In recent years, the Japanese company has been an active pioneer in the advanced field of portable audio equipment, releasing a number of state-of-the-art players and amplifiers. The PHA-1A is one of the highlights.

It is a compact amplifier that uses Olson’s WM8740 DAC chip and is compatible with Walkman, Xperia, and other players. It can also be easily connected to a laptop or PC using a USB cable or an iOS smartphone or tablet using a Lightning adapter.

Sony PHA-1A Classic Portable Headphone DAC/AMP Review

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PHA-1A Specifications

DAC: Wolfson WM8740 | Compatibility: PC, WM, Xperia, iPhone, iPad, iPod | Supported sample rate/ bit rate: Up to 192kHz/24bit | Frequency response: 10-100 kHz | Impedance: 8 – 600 Ohms | Maximum power: 148mW+148mW (8 ohms, 10% distortion), 80mW+80mW (32 ohms, 1% distortion), 16.4mW+16.4mW (300 ohms, 10% distortion) | Outputs: Stereo audio output connector, mini jack audio connector | Inputs: Digital audio input jack (USB micro B, USB type A) DC input jack (USB micro B) | Battery: 6 hours | Charging time: 3.5 hours | Weight: 145 g


The Sony PHA-1A USB DAC amplifier comes in an attractive two-layer box. The outer box is like a protective cover for the inner box. The inner box is plain black. The amplifier is inside the box on a cloth-covered catwalk, the manual is in a cutout in the lid, and the cable, silicone ring, and silicone pad are in a cutout under the catwalk. There is no charger.

The USB DAC Amplifier comes with a multi-language manual, a long USB cable for charging, a short cable for connecting to a source with USB output, a short cable for connecting to a Sony Walkman, two silicone bands for attaching the amplifier to your player or smartphone, and a silicone pad to hold it in place, so it doesn’t get scratched.

Design & Ergonomy

The device features an interesting design with rounded sides and a gold-plated headphone jack. The battery can run for up to 6 hours on a 2-hour charge. The case is made entirely of aluminum, with no plastic inserts as in FiiO, iBasso, or Cayin. Despite its confident appearance, the PHA-1A’s dimensions are very modest: 62.0 x 18.5 x 109 mm.

On the back, there is volume control, a battery LED indicator, and a 3.5mm headphone jack (minijack). On the front, there is a micro-USB and USB input, a “gain” switch, and a micro-USB port for connecting a charger.

This is a portable amp of the same size as the iFi Nano iDSD, but with a smaller battery. Despite the similarities, it cannot be used as an external battery (PowerBank) for your smartphone or player.

On the other hand, if your charger is good enough, you can use the DAC amplifier to charge your smartphone. If the charger is bad, only the amplifier will be charged. If the USB input of the amplifier is connected to a computer, the amplifier will not charge – charging will be done through the USB charging port.


The circuit uses a Wolfson WM8790 as a converter. The amplifier section uses a pair of LME49860 and TPA6120 chips. Sony claims you can use headphones up to 600 ohms, but with an 80 milliwatt output into a 32-ohm load, powering just over 150 ohms can be quite problematic.

The “Gain” switch, which is behind the brand’s significant statement, has two positions: “normal” – to connect headphones with low impedance, and “high” for connecting high-impedance headphones, which the manufacturer says can range from 8 to 600 ohms.

Although the amplifier supports a wide range of headphones, depending on their impedance, it only works with devices that support audio output via USB, i.e., computers, players, and smartphones (with OTG capabilities).

Note that not all players and smartphones support audio output via USB. Check the Sony website or the manufacturer of the player or smartphone to see if it has this feature before purchasing.

For connectivity, the PHA-1a compact amplifier is compatible with iPods, iPhones, and iPads. For Android devices, not all are supported. You do not need to install any special software to use it on your smartphone. Furthermore, if your smartphone is Android, you will need to install a player that supports the FLAC format.

The included short cable is suitable for devices with a micro USB output and Sony Walkman players. There is no short cable for connecting Apple devices. The short cable is suitable for devices with a micro-USB output, but to connect your iOS smartphone, you’ll need to use a longer cable, which may be uncomfortable to carry around, but you’ll get used to it over time.

Suppose you’re using it with a computer. In that case, you’ll need to download and install a Windows-compatible driver from the Sony website, starting with Vista and up to Windows 10. Installed Sony proprietary player (Hi-Res Audio Player) supports the following audio formats: MP3, WAV, AIFF, FLAC, ALAC, DFS, DFF.

Sound Quality

When I first listened to music from the Sony PHA-1A USB DAC amplifier, I was a little disappointed because it did not have any wow effect. However, when I listened to the same material without and without the DAC amplifier, the comparison made me realize there’s a slight improvement in the audio quality.

With the Sony PHA-1A, the sound was cleaner, more transparent, and more detailed, with better recognition of all instruments and more musical bass. The music is bright and atmospheric, with slight accents in the mids and highs. Bass isn’t as bad as some WM8740-equipped units, however, and the hard, powerful bass is especially good for listening to hard-hitting guitar rock.

The high-resolution support isn’t as good as the iFi micro iDSD, which supports PCM files up to 24-bit/192kHz, but it’s good enough for many audiophiles who don’t need ultra-high resolution. Overall, I think the PHA-1A amplifier is a satisfactory purchase in terms of sound quality.

I don’t think you can use cheap headphones with this DAC/AMP and get good sound. It may improve the sound somewhat, but not enough to justify the purchase of this device. In fact, very few amps can do that. On the other hand, it can highlight the positive traits in good-sounding headphones.


Compared to the XD-05, the Sony PHA-1A announced at CES 2015 has fewer audio jacks and only supports PCM up to 24-bit/192kHz. That doesn’t stop it from easily beating many of its competitors in this category, and it has excellent detail and a balanced sound that’s a little more prominent in the upper midrange and a little brighter.

Its sound is decent, the price is on-point, and the other two aspects that make a headphone amplifier suitable for traveling (size and weight) are fantastic. The amplifier is small (62×18.5x109mm) and light (145g). Meanwhile, the sturdy aluminum housing can withstand the toughest conditions, while the compact size and weight remove all objections against taking this gadget for a walk or a trip.

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