Astell & Kern AK HB1 Review

I’m a big fan of Astell & Kern’s sound, and I’ve owned a couple of their market leading DAPs over the years. So, I’m always excited to see their newest creations. The AK HB1 is Astell & Kern’s first portable Bluetooth DAC/Amp, hoping to join the likes of FiiO’s BTR5 and iFi’s Go blu in market popularity. What kind of features does the AK HB1 offer? And more important, how does it sound?

What’s in the Box?

• AK HB1 Portable Bluetooth DAC/AMP

• USB Type-C to USB Type-C Cable

• USB Type-C to Lightning Cable 

• Quick Start Guide 

• Warranty Card

Look and Build

The AK HB1 is compact little device, approximating the size of other best-selling DAC/amps, such as the FiiO BTR5 and iFi Go Blu, though the AK HB1 is admittedly boxier in its very Astell & Kerny way. The DAC is very lightweight, though not so light as to make it feel cheap or flimsy. On the right side of the device is a volume knob in addition to 3 thin sliver buttons that control a range of functions, such as Bluetooth pairing, track navigation and call answering. Between these buttons are two LED lights that indicate information such as the file type being played or the battery status. On the top of the DAC, you'll find 3.5mm and 4.4mm balanced outputs, while the bottom of the DAC has the USB-C input.

Design

Everything about the AK HB1 seems to be about making your life easier, but without a working app and a comprehensive user guide, you may be left feeling a tad stupid at times. The app didn’t work for me, but I would expect Astell & Kern to release an update soon. It’s a shame for now though, because the HB1 seems to have some useful features. In addition to an equalizer, the AK HB1 offers Bluetooth multi-point functionality. There’s a BT Priority Mode that allows you to receive a call from your phone, even while the USB DAC function is in use. But without the app, I have no way of knowing what mode I’m in or how to switch modes. Still, it seems like you don’t need the app for every application; the device also has a Car Mode, for instance, that turns on automatically once the AK HB1 is plugged into the vehicle’s AUX port.

Finally, one of the AK HB1’s big selling points is its compatibility with all kinds of gaming devices. Specifically, the HB1 supports UAC 1.0 connections in addition to UAC 2.0. And since many gaming devices still only support UAC 1.0 connections, the AK HB1 turns out to be a uniquely versatile DAC for gamers.

DAC

The AK HB1 incorporates ESS’s ES9281AC PRO DAC.

Power Output

The amp on the HB1 produces an impressive 4 Vrms output (balanced connection). To see how far I could push the AK HB1, I paired it with the Beyerdynamic DT 1770, which has an impedance at 250 Ohms. While there was little headroom, the AK HB1 did a decent job of driving the cans. So, while you may not be able to drive a super hungry planar magnetic headphone, for example, the AK HB1 is still no slouch.

Battery

You’ll get around 6 hours of battery life from the AK HB1. That said, the device is able to charge and be in use at the same time. The device takes about 1.5 hours to fully charge via USB cable.

Bluetooth

AK HB1 sports Qualcomm's CSR8675 Bluetooth chipset, and supports Bluetooth 5.0. Pairing was super fast and easy, and even in the middle of Manhattan, I never experienced any dropouts or interruptions. 

Hi-Res Capabilities

The AK HB1 supports Native DSD256 and 32 bit/384 kHz playback, in addition to its ability to render MQA files.

Extra Features

If you’re an audiophile who makes a lot of calls, the AK HB1 might be an optimal solution. The AK HB1 employs a 4-pole in-line MIC, and incorporates Qualcomm’s Clear Voice Capture technology, which minimizes ambient noise and enhances caller clarity.

As mentioned above, once the A&K updates its app, you should have in-app control over the device’s equalizer. In addition, you will be able to switch between DAC filters, as well as control other settings, like Car Mode and Device Priority.

Sound Impressions

What’s so impressive about the AK HB1 is that it sounds as almost as good as my Astell & Kern SR35 DAP, which is around 3 times the price. And although the presentation is relatively neutral, you will hear enhanced richness to the tonality and significantly improved transparency. You can also expect cleaner layering of instruments, in part, thanks to the immaculate separation that the AK HB1 delivers. And overall that highly controlled A&K character comes through in the performance, which always feels disciplined and tightly defined. Finally, while you shouldn't expect any magical transformation to your soundstage, you will get a touch of added depth and spaciousness in addition to more precise imaging overall.

Summary

While I am left feeling a little impatient for Astell & Kern to release an update to its companion app, there’s no question that AK HB1 sounds damn sweet. Super detailed and well-controlled, the AK HB1 delivers a sound quality that approximates its higher-priced players. So, if you don’t mind waiting for A&K to include a working app with equalizer control (and other neat features), you can at least rest assured that the AK HB1 sounds fantastic out of the box. 

You can buy the Astell & Kern AK HB1 at Audio 46.