Astell&Kern AK HB1 Portable Bluetooth DAC Amp Review & Comparison
Read Time: Approx. 11 min.
A Tiny Portable DAC/Amp Full of Functionality
One of the leaders in digital music players, Astell&Kern has ventured further into the world of Bluetooth HiFi devices with its release of the AK HB1 Portable Bluetooth DAC/Amplifier. With a powerful built-in headphone amplifier and Bluetooth connection, this tiny device is capable of wired and wireless playback for those who want to enjoy their favorite music on the go. Not to mention it’s packed full of features and functionality that rival high-end USB DACs more than twice the AK HB1’s size.
We’re big fans of Astell&Kern DAPs so we were excited to see if the AK HB1 could sit at the top with some of Astell&Kern’s best HiFi products. Let's jump right into it!
PROS
- Exceptional Wired and Wireless Playback
- Compact form factor travels great
- Packed full of features and functionality
- Car Mode and support for UAC 1.0, 2.0 Gaming
CONS
- Doesn't support the latest Bluetooth version and codecs
- Not enough power to drive power-hungry headphones
- No call functionality for iPhones when using USB DAC mode
Design
Astell&Kern's design approach with the AK HB1 is different from what we're used to seeing with many of their popular DAPs. Astell&Kern has opted for a lightweight polycarbonate chassis and a very compact form factor. It's small enough to fit into your back pocket, purse, or bag and weighs just under 1.5 ounces.
On the bottom of the HB1 you'll find the USB-C charging/input port and microphone. Included with the HB1 is a USB-C to C cable, a charging cable, and a USB-C to lightning cable. On the top of the HB1 is a 3.5mm unbalanced and a 4.4mm balanced headphone output. The three buttons on the side of the HB1 are the powerhouse of the entire unit. After a quick glance through the user manual, I was able to use the HB1 with ease. Each button hosts a number of functions that can be activated by quick taps or long presses. Below I'll quickly go into more detail on the functionality of each button.
Power On/Off
The first button which is closest to the bottom of the HB1 controls the power on/off and provides insight into charging and the battery level. To power on/off the HB1 hold the button down for three seconds until you see an LED light flash to indicate it's on. A short press of the power button allows you to check the battery status with several colors indicating the percentage. Blue= 100%; Green= 60-99%; Yellow= 20-60%; Red= 10-20%; Blinking Red= 1-10%. You can check the battery's exact percentage on the AK Control app as well.
Know that there is some unique functionality with charging and the HB1. Say you decide to use the USB DAC function on the HB1 and connect it directly to your Android or iPhone as the source device. The HB1 has a charging mode that when enabled defaults to using the battery of your source device to save the HB1's battery. This mode can be enabled and disabled on the HB1 by double clicking the power button.
Bluetooth Pairing Mode
The middle button is responsible for Bluetooth pairing allowing you to connect up to two devices at once to the HB1's built-in Bluetooth. To pair a device hold the button down for three seconds until the status LED light blinks blue and red. Once a connection has been formed the light will change to a solid white. To reset the Bluetooth pairing mode hold down the button for ten seconds until a green light appears accompanied by a tone. From there you can connect devices. The HB1 has a Bluetooth Priority mode that maintains a Bluetooth connection even when using the USB DAC function.
When paired in Bluetooth mode, both the source device's and HB1's volume controls are active. You can turn the volume up using the wheel on the HB1 or use your source device. It's pretty nice that you don't have to be glued to your source device to adjust the volume. When in USB DAC mode, the HB1 is your sole source of volume control.
Connecting in USB DAC mode
The USB DAC mode will connect automatically when you connect a source device and the HB1 via a USB-C cable. When connected in USB DAC mode the status LED light turns white.
Playing Music, Voice Calls
The top button controls play/pause, track skipping, as well as accepting and declining incoming calls. Press the button once to play/pause and accept/end a call. Quickly press it twice to play the next track and quickly press it three times to play a previous track. To decline a call hold the button down for more than one second. When music is playing the status LED light will change colors based on the streaming format. A red light indicates music is being played in PCM, blue indicates DSD, and magenta indicates MQA Renderer.
When the HB1 is paired in Bluetooth mode and connected to your mobile device, the HB1 will use its built-in microphone for calls. When connected in USB DAC mode or to an Android, the HB1 will default to using your earphones/headphones built-in microphone. Call functionality is not supported on iPhones when using the USB DAC mode.
Sound
The AK HB1 uses an ESS ES9281AC PRO DAC chip that's designed to deliver exceptional noise control and high-quality HiFi sound. The HB1's sound signature is neutral with amazing musicality and clarity. The sound was clear and resolving without being overly analytical and had just enough detail. Charlie Puth's latest hit Lipstick starts with a keyboard melody that's funky and full of life. The HB1 emphasized the already funky melody adding just the right amount of musicality to it without making the sound overly warm and muddy. You won't get an overwhelming amount of bass — It's pleasant and non-fatiguing on the ears, just enough to make songs dynamic and fun. I thoroughly enjoyed the sound it delivered to over-ear headphones when paired with the Focal Celestee headphones and our Blue Dragon Headphone Cable.
As a portable device, it was only natural to pair the HB1 with the Sennheiser IE600 In-ear monitors and our Bronze Dragon IEM Cable. The IE600 IEMs are one of our top choices for podcast and audiobook listening so it's no surprise they were the perfect combo with the HB1 for spoken word and entertainment. I was pleased to experience a level of noise isolation with the IE600 and the HB1 that made my listening experience fairly immersive.
The HB1's Bluetooth connection was equally impressive with the Focal Celestee and Sennheiser IE600. The AK HB1 supports Bluetooth version 5.0 and when connected to my Apple iPhone configured with the SBC Bluetooth codec. When paired with my phone I didn't notice any downgrades to the sound quality that would turn me away from using the HB1 wirelessly. For someone looking to use the HB1 strictly in Bluetooth mode with portable headphones, you won't be disappointed.
The HB1 delivers a level of sound that's so impressive it makes it a downright steal for the price point of the device. It can drive the majority of IEMs and low-impedance headphones you throw at it so you can sit back and enjoy a musical, clear, and accurate sound from the HB1.
Lipstick
by Charlie Puth
Daylight
by Harry Styles
(Harry's House)
Eventually
by Tame Impala
(Currents)
Rose Colored Lenses
by Miley Cyrus
(Endless Summer Vacation)
Features
Don't let the size of the AK HB1 fool you — It's packed full of features! Connect up to two devices wirelessly with multi-point connection and answer calls using the HB1's built-in microphone. Connect the HB1 to your favorite portable gaming device and enjoy immersive, enhanced sound effects. And even amp up your car's audio setup by syncing the HB1 with your car's audio system so you can reap the benefits of its DAC and Amplifier.
Car Mode
The car mode was one of the things I was most excited to test out when I first received the AK HB1. I'm always on the hunt to find new ways to amp up my car's audio setup and I was not disappointed by the HB1's performance. Within the AK Control app, you can enable and disable the car mode, which when enabled syncs the HB1 and your car's ignition so the HB1 will turn on/off automatically with your car.
The HB1 must be connected through an aux input in your car so if you don't have an aux port this feature may not be relevant to you. I did test the car mode using the USB port in my car with a USB-A to USB-C cable but was unsuccessful at making a connection. I used a Black Dragon Portable Mini Cable V2 with 3.5mm to 3.5mm connectors to connect the HB1 to my car. Once recognized by my car I connected my iPhone to the HB1 via Bluetooth and successfully played music through the car speakers.
You can control the volume output on both the HB1 and your car's stereo. I immediately noticed a difference in the volume level — I didn't have to turn the volume up nearly as loud as I normally have to on my stereo. I was able to comfortably sit at around level 10 volume output on the car stereo and control the volume through the HB1, cranking it up to what sounded close to 20 without busting my stereo speakers. That's one of the best perks about the car mode in my opinion. The sound quality was much better than what I'm used to with my car's rinky-dink audio.
Support for UAC 1.0 & 2.0 for Gaming
We've got quite a few gamers here at Moon Audio so when we learned the AK HB1 has high compatibility and support for UAC 1.0 and 2.0 for gaming we were stoked! UAC stands for USB Audio Class and similar to Bluetooth versions, different classes determine the speed of audio data transmission and the sound quality you'll receive. With UAC 2.0 you're going to get higher-quality sound at a faster rate than UAC 1.0. Astell&Kern said they opted to include support for both UAC 1.0 and 2.0 as many smartphones, tablets, and PCs support UAC 2.0 while many gaming devices still support UAC 1.0.
We released a blog rounding up the best IEMs and earbuds for gaming so it was only fitting to test the HB1 with the Sennheiser IE600 In-ear monitors. The AK HB1 connects to your gaming device using the USB DAC function with a USB-C to USB-C connection, depending on your gaming device. We used our Black Dragon USB Cable with a USB-C to USB-C connection for our testing. The sound quality delivered by the HB1 when gaming was downright impressive. I was immersed in a cinematic experience that usually only the best headphones and gaming headsets can deliver. Tiny details like footsteps, reload sounds, etc. were emphasized giving you that spatial recognition that's an edge in competitive gaming. You can expect an incredibly wide soundstage with low latency, amplified sound effects, and excellent detail retrieval.
AK Control App
Through the AK Control App, you can access the settings of the HB1 as well as check the battery percentage, manage the multi-point connection, and enable car mode. The HB1 has a DAC filter with three options that can be adjusted on the app: A linear phase fast roll-off, a minimum phase slow roll-off, and a hybrid fast roll-off. View the user guide and adjust the tonal quality using the equalizer on the app as well.
Comparison to the iFi Audio GO Blu Headphone Amp/DAC
Two tiny portable devices battling it out to be the best — The AK HB1 versus the iFi Audio GO Blu Headphone Amp/DAC. The GO Blu Headphone amp/DAC was released at the beginning of the year as an extremely compact portable Amp/DAC with a built-in microphone. In many ways the iFi GO Blu Amp/DAC and the AK HB1 are similar. Both devices have built-in mics, built-in digital-to-analog converters, and integrated headphone amplification, and deliver audiophile-grade sound in a tiny package. But what makes them different?
First and foremost the iFi GO Blu is almost half the size of the AK HB1. Both devices can fit in the palm of your hand but the iFi GO Blu takes the cake as one of the smallest portable DAC Amps I've seen. The GO Blu has a slight leg up in the wireless Bluetooth department over the AK HB1 with Bluetooth 5.1 technology over the HB1's Bluetooth 5.0 technology and aptX Lossless codecs. iFi also implemented its proprietary XSpace and XBass sound enhancements into the GO Blu. Both products have balanced 4.4mm and unbalanced 3.5mm headphone jacks with the option to listen wirelessly via Bluetooth or wired via USB to your source device.
The AK HB1 has a battery life of 6 hours whereas the GO Blu has two more hours of playback. As with all batteries, it really depends on what you're running as to how much battery life you'll get from a full charge. The AK HB1 is more feature-rich than the GO Blu with its car mode, gaming support, and multi-point connection.
Without the XSpace and XBass modes activated on the GO Blu the sound is more analytical, but you're given the option to adjust the sound based off your preference. The GO Blu features a Cirrus Logic CS43131 DAC chip which lends itself to a sound that's transparent, accurate, and full of clarity and detail. The HB1 has a more musical sound than the GO Blue with a more spacious soundstage. Personally, I am more fond of the HB1’s sound simply because I enjoy a warm and musical sound. However, the GO Blu’s XBass mode will deliver you a warmer sound that's closer to the HB1's sound. If you enjoy a more analytical sound that's transparent and accurate then the iFi Audio GO Blu will be for you. But if you love musicality and enjoy a sound that's neutral and detailed, then the HB1 is a great choice. You can’t go wrong with either piece of audio gear but the HB1 has slightly more to offer in terms of functionality and features for the price.
Dragon Cable Recommendation
When using the AK HB1 as a USB DAC we recommend our Black Dragon USB Cable. Why? Our Black Dragon Cables are made with only the purest UP-OCC Copper conductors for the best possible signal transfer for your digital music. You can choose the connector types you'll need whether that's a USB-A to USB-C connection or a USB-C to USB-C cable. Yes the AK HB1 comes with stock cables so why would you want to upgrade? Let me explain.
Generally, stock audio cables are manufactured with subpar materials, metals with impurities, poor geometries, and an overabundance of layers to make them look and feel like a fire hose. Inconsistency and lack of quality control in stock cables can lead to poor sound quality and a veiled sound vs what the musician intended for you to hear and feel from the music. Dragon cables are handcrafted with the highest standards and made to order according to your specific needs. At Moon Audio, we create a custom cable for you using the highest quality UP-OCC silver or copper conductors that can be manufactured. UP-OCC metals are void of impurities and are optimized for signal transfer and sound quality. We have one of the largest collections of audio and headphone connection options available online and we create limitless audio cable options depending on your specific gear and needs.
For the ultimate listening experience with the AK HB1 we also recommend upgrading your stock headphone cable. Our Blue Dragon Headphone Cable is going to deliver you a sound that's clear, neutral, and uncolored. We also have a silver dragon and black dragon headphone cable, each with unique sound signatures that will compliment only the best headphones. You can enjoy improved dynamics and a level of sound that stock cables dream of delivering. If you're looking to upgrade your IEM cable, we make those too! In fact, we just relaunched our MMCX connections which fit the Sennheiser IE600 IEMs. We make headphone and IEM cables with various connectors so you’re guaranteed to find the perfect fit for your pair of cans.
And if you're like me and want to amp up your car's audio setup with the HB1, our Black Dragon Portable Mini Cable V2 with 3.5mm to 3.5mm connectors is going to be just what you need. Our Mini Cable V2 comes with a variety of connector options so you can customize the cable to fit your car's audio setup.
Why Dragon Cables?
You’ve heard the saying that a chain is only as strong as its weakest link, right? Well, the same applies to your brand-new audiophile-grade headphone or other audio components. The weakest link, in this case, is your stock cable or the cheap interconnects the manufacturer threw in the box just to get you up and running. Why is the cable always an afterthought, when it’s just as important as the rest of your system? At Moon Audio, we use the best raw materials in our cables to unveil your music. We believe the materials matter and your audio cables should have the same care and craftsmanship that manufacturers put into their audio components and headphones. Audio cables are ultimately the connection to your music. The fact remains that cabling is often considered the last priority to that of the main product and a means to cut down the overall production costs. It’s as simple as that.
Silver Dragon Sound Signature: The Silver Dragon is the original cable. Silver strands clarify instrument separation, increase the soundstage, and find previously lost high and mid-frequency sounds. Transients appear more cohesive and the bass is tighter for a more controlled sound. The detail and clarity of the Silver Dragon make it a perfect match for classical music and other genres with many nuanced instruments.
Black Dragon Sound Signature: The Black Dragon is warm and smooth with a musical presentation. Copper strands enhance the body, shape, and immediacy of the music. The detail and expansiveness of the Black Dragon make it a flexible fit where a broad range of musical genres are played. It can also improve bass frequencies on bass-light headphones. The smooth, musical quality makes it a perfect fit for headphones that tend to sound a bit edgy or bright. Despite its warmth, the Black Dragon does not have a laid-back, lush sound. It is much closer to neutral, making it a very natural-sounding cable. For more information on finding your signature sound, visit our Sound Signature Guide.
Verdict
For $259 the price-to-performance ratio is clear — You get exceptional sound from a tiny portable device that’s packed full of features and functionality. The ESS ES9281AC PRO DAC chip delivers you an audiophile-grade sound that’s musical, transparent, and full of detail regardless of whether you’re listening wirelessly or wired. The functionality of the AK HB1 is not limited to portable use. You can add this to your current home audio desktop setup and integrate it as your desktop DAC to transform how you game on your PC. Utilize the Car Mode capability and amp up your car's stereo system or connect your smartphone and laptop to the AK HB1 so you never miss an incoming call. You can’t go wrong with the AK HB1 as your on-the-go listening companion and for the price, this little device isn’t going to let you down.
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What's in the Box
- AK HB1
-Charging Cable
-USB-C to Lightning Cable
-USB-C to USB-C Cable
-Quick Start Guide
-Warranty Card
-Device User Guide
Specifications
Audio Specifications
Bluetooth:
Chipset: Qualcomm CSR8675
Version: 5.0
Codec: LDAC, aptX HD, aptX, AAC, SBC
Profile: A2DP, AVRCP, HFP
DAC: ESS ES9281AC PRO
Sample Rate:
PCM: 8kHz ~ 384kHz (8/16/24/32bits per Sample)
DSD Native: DSD64(1bit 2.8MHz), Stereo / DSD128(1bit 5.6MHz), Stereo / DSD256(1bit 11.2MHz), Stereo
Output Level: Unbalanced 2Vrms / Balanced 4Vrms (Condition No Load)
Input: USB Type-C (Supports UAC 1.0 and UAC 2.0)
Output: 3.5mm (Supports CTIA standard 4-pole earphones/headphones), 4.4mm (Only 5-pole supported)
Frequency Response: ±0.135dB (Condition : 20Hz~20kHz) Unbalanced │ ±0.136dB (Condition : 20Hz~20kHz) Balanced
S/N: 117dB @ 1kHz, Unbalanced │ 118dB @ 1kHz, Balanced
Crosstalk: -112dB @ 1kHz, Unbalanced │ -112dB @ 1kHz, Balanced
THD+N: 0.0005% @ 1kHz, Unbalanced │ 0.0005% @ 1kHz, Balanced
IMD SMPTE: 0.0003% 800Hz 10kHz (4:1) Unbalanced │ 0.0003% 800Hz 10kHz (4:1) Balanced
Output Impedance: Unbalanced Out 3.5mm (2.5ohm) │ Balanced Out 4.4mm (2ohm)
General Specifications
Model: AK HB1
Body Color: Shadow Black
Body Material: Polycarbonate (Body) / Aluminum (Volume Wheel)
Battery:
Capacity: 600mAh 3.8V Li-Polymer
Charge Time: About 1.5 hours
Playback Time: About 6 hours (Standard: AAC)
Dimensions: 33mm [W] x 68.4mm [H] x 16.5mm [D] (Excluding volume wheel) | 39.8mm [W] x 68.4mm [H] x 16.5mm [D] (Including volume wheel)
Weight: About 1.41oz (40g)
Feature Enhancements: Firmware upgrade supported
