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Prior to the PHA-3 headphone amplifier, Sony had long focused on the consumer segment. Still, as consumers confidently turned to more advanced audio products, Sony decided to move upmarket, which encouraged the production of a high-end portable headphone amplifier.
The goal of the PHA-3 was to create a reliable amplifier for the MDR-Z7 and meet consumer demand for more professional audio equipment. Of course, $700 headphones are unlikely to work at full volume on a smartphone or standard player, and the PHA-3 is an excellent choice, although a bit over-the-top. It’s powerful and versatile and can be connected to virtually any device. Whether it’s a computer, an external digital music source via an optical connection, or an Android or iOS device, there’s also a line input, so the PHA-3 can serve as a DAC/AMP (though it’s not the most powerful).
For advanced users, the PHA-3 is capable of handling high-resolution recordings at 384kHz/32bit (the current maximum) and DSD. Another interesting feature of the PHA-3 is that it can be used with balanced headphones, with two channels connected separately. It is not surprising that such a device is not compact and inexpensive. Its large size and weight are justified by its whopping $1,000 price tag, but is it really worth it?
Sony PHA-3 High-End Portable Headphones Amplifier Review
Sony PHA-3 Specifications
DAC: ESS Sabre ES9018S | Amplifier circuit: 6120A2 | Frequency range: 10 Hz – 100 KHz | THD: <0.01% or less @ 1 kHz | Load impedance: 8Ω – 600Ω | Maximum input voltage: 2Vrms | Output power: 100 mW @ 32 Ω/channel in normal mode, 320 mW @ 32 Ω/channel in balanced mode | Outputs: 3.5mm TRS headphone output jacks, 2 x 3.5mm TRS balanced | Inputs: 3.5mm TRS line input, micro USB for PC/Mac/Android/Walkman, USB for iOS devices, optical | Power: 3.7V from the internal battery, 5V from USB | Supported sampling frequencies / bit: Up to 384kHz/32bit, DSD: 2.8MHz, 5.6MHz, up to 48kHz/24bit (iOS), up to 192kHz/24bit (optical link) | Weight: about 300g
Package
Given its $1,000 price tag, the PHA-3’s amplifier packaging has been carefully designed to convey the product’s image. As with the MDR-Z7, the box is composed of two layers. The outside is a glossy white and black cardboard, while the inside is thick black cardboard. It opens in the middle. On one side is the amplifier itself and on the other side are the accessories.
The package content is nice too, and comes with the following:
- USB cable for connecting to a PC or charging
- MicroUSB cable to connect Android devices
- Cable for Walkman devices
- Speaker cable with two 3.5mm TRS angle connectors
- Two pairs of rubber rings to connect the amplifier to the player or smartphone
- Rubber pad to protect player/smartphone
- Instruction manual
As expected, there are no complaints on this.
Design & Ergonomy
For a DAC & Amp combo, the Sony PHA-3 is very small, and at 0.66 pounds, it is also very light. The housing is all metal and black. The metal has a pleasant roughness and practically does not slip in your hands. The build quality is not bad, but it lacks a luxurious feel; and on the interior, the DAC chip used is the ES9018 from ESS Technologies.
The PHA-3 high-performance portable headphone DAC/AMP has three USB ports:
- A full-size port for transferring music from an iOS device
- A micro-USB port for transferring signals from a computer or smartphone
- A micro-USB port for power (DC5V).
There is also an optical input and an analog signal input. There is also an optical input and a 3.5mm jack for analog signal input and output.
On the front, you’ll find a combination of volume controls, an on/off switch, LED indicators, and three output jacks. What’s a little confusing is that Sony didn’t use one of the jacks as a balanced output, as it considers balanced output to be two 3.5mm jacks. If you have high-end headphones and bought a balanced cable, you’ll need to get an adapter or change the jack used.
The output jacks include three 3.5 mm headphone jacks, one of which is a normal stereo output and the other two are for balanced headphones. On the left is a gain switch and a DSEE HX audio gain switch. There are long rubber strips on the top and bottom of the case to prevent the PHA-3 from getting scratched.
The harshest criticism of the PHA-3 is its battery: it runs for just over five hours on a single charge in DAC mode. Charging via a standard USB port takes about 15 hours, but that time is reduced when the device is charged with an external charger. Surprisingly, the PHA-3 does not turn on when the battery is dead and can only be charged when turned off.
The built-in battery does not improve the handling of the DAC but rather serves to smooth out the power of the audio circuits. The battery cannot power the DAC itself. On this note, Sony’s built-in battery, its short life, long charge time, and inability to power the DAC are aspects that make the PHA-3 very trivial and embarrassing considering the price tag.
Technology
The PHA-3 is based on a highly advanced ESS Sabre ES9018S chip, which offers a dynamic range of about 133dB with less than 0.0001% distortion. The headphone amplifier uses two Texas Instruments 6120A2 chips. Sony’s innovative portable amplifier supports PCM and DSD formats up to 384kHz/32bit with sampling rates of 2.8MHz and 5.6MHz. Power is provided by a dedicated micro-USB connector; a separate AC adapter is also required.
In addition to formats up to 32bit/384kHz, the Sony PHA-3 supports 64/128 DSD streams, but playback of DSD files requires the use of Sony’s Hi-Fi audio playback software in Mac or PC version.
The DSEE HX feature is designed to improve the sound quality of compressed files and can be activated by a switch on the device. Overall, it works well, with better saturation at higher volume levels and louder sound. Even though the five-hour battery life is a bit short, it results from very good quality amplification. A three-position gain selector also allows wide compatibility with many headphones and earbuds.
Sound Quality
Since the power of the device is not the best part of the amplifier, nor its versatility in the area, the sound quality should offer excellent musicality. The 32-ohm headphones deliver a maximum of 100 milliwatts per channel with an unbalanced connection, compared to 320 milliwatts with a balanced connection. With an unbalanced connection, the average power per channel is 100 milliwatts. With an unbalanced connection, you will have to sacrifice headphones with below-average sensitivity.
When the PHA-3 headphone amp is used with the Meze Audio 99 Classics or the HiFiMan HE-300, the sound detail is fantastic. It is almost neutral, with no noticeable harmonics or irregularities. If the PHA-3 were $200-$300 cheaper, we wouldn’t have any complaints, but complaints do arise because we wished for more, considering it’s an expensive device. But it’s also important to not forget that there aren’t many high-end portable amplifiers with DAC capabilities that are as powerful and compact as PHA-3.
With the Sennheiser HD 650 or Sennheiser HD 660 S, the music is interesting, loud, detailed, and three-dimensional. But that’s not all; I found that using monitor headphones like the AKG K701 gave me the kind of sound I was hoping to get with the EQ and various enhancement software.
Bass
The bass was tight and very dynamic, but some headphones lacked bounce. Dynamics were good, but it’s worth noting that the attack phase was more accurate and responsive than the decay phase. This amp has better control of sharp and fast sounds.
Mids
The mids are impeccable and played with adequate control and emotion. Even the most subtle nuances in this range are reproduced with remarkable accuracy. Each instrument is perfectly outlined and retains its own personality, and imaginary scenes are very well constructed in terms of depth and width.
Highs
The highs are not bad either. However, in the company’s ambitious quest to reach the 100 kHz ceiling, the amplifier loses the naturalness of the ultra-high frequencies. There is a slight but noticeable artificial coloration in the high range, which is not a problem in cheaper equipment but becomes apparent and bothersome in high-end audio equipment. Fortunately, this problem occurs only with a limited number of headphones and audio sources.
Naturally, the PHA-3 works great with Sony equipment. This applies to both players and headphones. Almost all combinations turn out very well, but of course, with the freshly introduced MDR-Z7, the synergy is particularly complete. I think that’s what the PHA-3 was designed for.
The PHA-3 gives no preference to any one genre of music or file format, and whether you play music on a smartphone or high-quality audio player, the device is good in both cases. Basically, it’s not quite an amplifier. Instead, it is a full-fledged external sound card. The sound is very good. You can say that it is of professional quality. Especially nice to listen to Flac-format audio files, making you feel like you’re in a recording studio.
Conclusion
The PHA-3 headphone amplifier is a well-made but controversial audio product with some design flaws, but overall a nice product. In terms of sound, it is exemplary and always reproduces audio content cleanly and without any discernible background noise. Once you experience the air, balance, detail, and ultimately great sound, it’s hard to pass up on Sony PHA-3.
It is the fans of the brand that will love the professional portable amplifier. If you’re a fan of Sony’s iconic sound and want to use Sony headphones, you’ll have a hard time realizing the potential of your headphones without this unit.
For everyone else, we suggest you test the PHA-3 on your device and decide for yourself if you can handle the charging issues. If that’s not a problem, the PHA-3’s good sound and rich inputs make it a very interesting hi-fi device that’ll complement your set of hi-fi audio products.