Verdict

Pros

• Light, compact design
• aptX HD support
• Balanced headphone output
• Loud, detailed sound with plenty of bass

Cons

• Lacks USB DAC functionality
• Plastic casing

What is the Astell & Kern XB10?

This is a bite-sized Bluetooth headphone amplifier. It supports Qualcomm’s aptX HD codec, which allows you to stream 24-bit hi-res music wirelessly from compatible devices. With a high-quality 192kHz/24-bit DAC and a specially tuned analogue amplifier, the XB10 has the muscle to drive high-end, high-impedance headphones – and make them wireless in the process.

It’s also a terrific way of adding Bluetooth to home or in-car audio systems that don’t have it built in, as well as overcoming the lack of a headphone jack on the iPhone 7. Is there no end to its talents? Let’s find out…   

Related: Best Bluetooth Speakers

Astell & Kern XB10 – Design and Connections

The XB10 is a black disc with a diameter of just 50mm, about the same size as those small tins of lip balm. It’s light, compact and easy to slip into a pocket, but for added hands-free convenience you can attach the supplied clip and hook it onto your shirt or bag.

The design is deceptively simple and attractive. Its top surface is divided into sloping quadrants that create four buttons – volume up and down, Bluetooth pairing and play/pause. According to A&K, it was designed to mimic the scattering of light from a star, because Astell means “star” in Greek. Who knew a headphone amp could be so poetic?

You’ll find further controls on the side, including a power switch that also locks the buttons when pushed the other way – handy for guarding against accidental in-the-pocket button presses. Alongside it is a tiny LED that glows red when charging and flashes blue when pairing with a device. On the opposite side are track-skip keys.

The XB10 provides a regular unbalanced 3.5mm jack and a 2.5mm balanced connector, the latter helping to reduce detrimental ground noise. You’ll also find a micro-USB port for charging. Disappointingly, you can’t connect a smartphone or PC and use the XB10 as a USB DAC, as you can with Creative’s Sound Blaster E3.

Although the XB10’s build quality falls short of A&K’s luxurious music players, it’s solid enough to withstand the rigours of the daily commute. The plastic casing and buttons are flimsier than I was expecting, but that makes it incredibly light – at 23g you’ll barely know it’s there.

Astell & Kern XB10 – Features

The XB10’s key feature is support for the Qualcomm aptX HD codec, which allows you to transmit 48kHz/24-bit audio via Bluetooth 4.1. Its designed for hi-res audio, but Qualcomm says it will give regular music a boost too.

Of course, you need a device that supports it. The range is still limited, but includes several Astell & Kern hi-res audio players (AK300, AK320, AK380, AK70), the Naim Uniti2 and Uniti Star and the LG G5 smartphone. The XB10 also supports regular aptX and SBC for Android devices and AAC for iOS. You can pair two devices simultaneously.

The XB10 is equipped with a 192kHz/24-bit DAC and analogue amplifier. The amp is designed with a “driving” concept that focuses on boosting weak signals, so it doesn’t get caught out when powering high-impedance headphones.

The XB10’s battery life is quoted at five hours, but I managed to get a full day’s use out of it on a single charge – admittedly, with lots of stopping and starting. When it drops below 10%, the red light flashes and you’ll hear a beep.

When paired with your phone, you can use the XB10 to take calls hands-free using the built-in microphone. Just press the play button to take the call and long press to hang up.

Astell & Kern XB10 – Performance

Paired with a Sony NWZ-F886 hi-res audio player (which offers regular aptX, not aptX HD), the XB10 delivers excellent sound quality through our Audio Technica ATH-MSR7 headphones.

Most impressive is the power on offer. It might be small but it packs a hell of a punch. If you like your music loud then the XB10 is a satisfying listen, giving you a big, brain-wobbling sound when you need it.

I compared it with the headphone outputs on the Sony player, as well as a Samsung smartphone and an iPod, and for my money the XB10 goes louder than all three.

Admittedly, it loses focus when pushed hard, straining slightly in the high frequencies and thickening up a touch, but we’re talking about volume levels that only a duty-bound reviewer would dare to explore.

Bass notes are deep and muscular, but well harnessed. Kick drums and basslines punch and pulse without overpowering the other frequencies. The sense of depth underpinning every song really warms the cockles.

The mid-range is populated by clear, natural-sounding saxophone solos and full-bodied vocals. Excitement is guaranteed by the XB10’s impressive top-end attack and vigour. Snare drums have a crisp leading-edge and percussion sparkles. But there’s no resonance or harshness; nothing to make you wince – it’s a clean, well-balanced presentation.

There’s plenty of detail, too. It teases out nuances in vocals and instruments, while the clear, well-separated hi-hats and shakers provide a good sense of air and space. Its wide soundstage puts you in the middle of the music.

Something called Distinctive Clear Technology (DCT) aims to remove noise and improve clarity, but I didn’t notice any difference when turning it on and off.

Also impressive is the XB10’s wireless range, which allowed me to stray more than 10m from the music device without any break up. It’s also helpful how it connects automatically to the device without having to re-pair them every time.

Should I buy the Astell & Kern XB10?

If you want an affordable way of driving high-end headphones while out and about then the XB10 is a terrific purchase. This impressive bite-size Bluetooth amp delivers excellent sound quality, decent battery life and plenty of useful features.

Hi-res music streaming via aptX HD, combined with a balanced headphone port, will make the XB10 a popular choice among audiophiles. It’s also a great way of adding Bluetooth to non-wireless systems at home or in the car.

On a practical level, its light, compact design is easy to slip into a pocket and means you’re not tethered to your phone or music player by a cumbersome cable. The plasticky construction and lack of USB DAC functionality are the only real negatives.

Verdict

Light, compact and equipped with industry-first features, the XB10 offers superb wireless sound wherever you go – although the lack of USB DAC functionality is a pity.

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