Astell&Kern AK UW100 MKII: more than a simple revamp

The Astell&Kern AK UW100 MKII True Wireless earbuds, successors to the AK UW100, have the same winning formula but now feature better battery life, more comprehensive configuration and a 32-bit AKM DAC for precise sound. The perfect combination of musical performance and original design.

Included accessories

The Astell&Kern AK UW100 MKII True Wireles earbuds come with five pairs of silicone ear tips. The latter provide the perfect fit inside the ear and ensure optimal comfort for every user. In addition, the box also contains the USB-A to USB-C charging cable, as well as several leaflets.

A look at the Astell&Kern AK UW100 MKII’s characteristics

The Astell&Kern AK UW100 MKII earphones are the second pair of True Wireless earbuds from the South Korean brand, which is mainly known for its DAPs. Notable models include the Astell&Kern A&norma SR35, Astell&Kern KANN MAX and Astell&Kern A&ultima SP3000. Its arrival on the IEM market with the AK UW100 earbuds was well received by users. Let’s take a look at the updates carried out by the manufacturer.

Meticulous and elegant design

This second edition has the same visual design and the Astell&Kern UW 100s, which we have also reviewed. The earbuds are identical, with their trendy angular design. This time, their finish is various shades of gray. 

Like the first generation, the earbuds are easy to insert and rotate. However, the comfort of the Astell&Kern AK UW100 MKII could be better. Their large size and angular design can be uncomfortable for those with smaller ears. While this may be tolerable for short trips, it can detract from the experience during longer listening sessions.

The case has a brand-new look. The power supply system has been redesigned, considerably reducing the size of this Astell&Kern charging case.

Modified audio design

The brand’s first model was the embodiment of Astell&Kern’s goal to “deliver music that is true to the original sound.” The Astell&Kern AK UW100 MKII pursue this goal with an improved configuration and a new DAC.

The manufacturer has incorporated a high-end 32-bit DAC (AKM AK4332ECB) inside its earphones, a true feat. This convertor ensures perfect signal conversion and provides a highly precise reproduction as a result. Note that it remind limited by Bluetooth, which doesn’t support Hi-Res except for LDAC/Bluetooth HD.

Moreover, the Knowles balanced armature transducers promise a wide frequency response. Their position is now closer to the inside of the ear to provide better detail perception. To do this, the structure of the acoustic chamber and the mesh size have been adjusted to achieve an optimal sound output.

In addition, the architecture of the internal circuit is more advanced, offering a more stable connection and drastically reducing distortion and unwanted noise.

aptX Adaptative Bluetooth

The Astell&Kern AK UW100 MKII earbuds have the same QCC5141 Bluetooth chip, with support for the SBC, AAC and aptX Adaptive codecs. The latter combines the advantages of the aptX HD and aptX HD Low Latency codecs to provide perfectly synchronized image and sound when watching videos. It adjusts the bit rate according to the content or wireless environment, and supports 24-bit up to a bit rate of 420 kbps.

Furthermore, the Astell&Kern AK UW100 MKII True Wireless earbuds now offer the multipoint feature. The latter lets you connect your IEMs to two devices, such as a telephone and a computer, simultaneously. This way, you won’t miss any calls!

Passive isolation levels

Like the previous model, the Korean manufacturer has chosen to equip the Astell&Kern AK UW100 Bluetooth earbuds with a “PNI” or “Passive Noise Isolation” system. This design eliminates exterior sound without having to use an active noise cancelling system, which could generate distortion.

The Astell&Kern AK UW100 MKII’s passive isolation relies greatly on choosing ear tips that fit correctly. To ensure a perfect fit for all users, the earbuds come with five different pairs of silicone ear tips in various sizes.

The Astell&Kern AK UW100 MKII True Wireless earbuds are also equipped with a transparent mode. The latter bypasses the excellent passive isolation so that you can hear ambient sounds at the same time as the music. It is activated simply by pressing the left earpiece. Note that the control app lets you customize this mode, which has four levels.

Although unconventional in this price range, the manufacturer’s decision to dispense with active noise cancellation proves to be a wise one. The passive isolation offered by the earphones is effective, and their ability to switch effectively to transparent mode makes them versatile travel companions. They proved very practical in an open space office, as well as on the street.

Improved battery life

The Astell&Kern AK UW100 MKII Bluetooth earbuds’ battery life is significantly greater than that of the previous generation. The in-ear monitors ensure 9h30 of playback per earbud, and up to 29 hours with the charging case. Compatible with both wireless and fast charging, these earphones are highly convenient.

It is also possible to activate the automatic pause feature via the app. This lets you optimize the earbuds’ battery life without missing a single note. Also, each earbud can be used independently, in hands-free call mode.

Control app and touch-sensitive controls

A touch-sensitive control is located on the surface of each earbud, enabling simple actions to be performed by pressing the earpiece, such as managing music playback, answering calls, adjusting ambient volume levels, controlling the voice assistant, etc.

Unfortunately, when using the earphones’ touch interface, you can sometimes hear microphonic noise similar to the friction of the cable on certain wired earphones.

The Astell&Kern AK UW100MKII earphones can also be controlled using the AK Control app, available for iOS and Android. The latter provides access to various settings. You can see the battery level, adjust the custom equalizer, modify the touch-sensitive control, activate the transparent mode, and more.

They support Google’s Fast Pair service for easy and quick pairing with Android devices. By simply opening the case near an Android device, it switches to pairing mode, avoiding the need to go through the Bluetooth settings.

Clear calls

The Astell&Kern AK UW100MKII earbuds ensure crystal clear phone calls. The two optimized microphones also feature Qualcomm’s cVc 8.0 (Clear Voice Capture) technology. This effectively suppresses background noise to ensure optimum voice clarity.

Key specs

Knowles balanced armature transducers
DAC: AKM AK4332ECB
Bluetooth 5.2 with support for the SBC, AAC, aptX Adaptive codecs
Touch-sensitive controls
Microphones: 2 per earbud
Battery life: 9H30 and up to 29h with the charging case
AK Control app for Android and iOS
Weight: 7g (earbuds), 65g (case)

Are the Astell&Kern earbuds Hi-Res?

To test the Astell&Kern AK UW100 MKII wireless earbuds, we paired them with an aptX-compatible smartphone and an HP laptop. We listened to Hi-Res music streamed rom Qobuz. To test the passive isolation, we used the earbuds in an open space office, in public transport and in the street.

Listening impressions

The Astell&Kern AK UW100 MKII True Wireless earbuds provided a very clear sound. When listening to Nina Simone’s Feeling Good in Bluetooth aptX, we were transported to the heart of the music, surrounded by well-spatialized instruments with rich timbres. In addition to an incredibly natural reproduction, the soundstage felt spacious. Each musical element was perfectly positioned, creating an immersive listening experience. 

When we listened to Hey Ya! by Outkast, the Astell&Kern AK UW100 MKII True Wireless earbuds revealed dynamic bass. Even when the equalization was deactivated, the bass remained clear and well-defined. The highs were smooth, and the vocals were perfectly highlighted. 

The customizable equalization mode that was missing from the first edition has now been added. This 10 band equalizer lets you adjust the sound depending on your preferences or the music genre you’re listening to.

Astell&Kern AK UW100 MKII VS Bang & Olufsen Beoplay EX

Thanks to their more ergonomic design, the Bang & Olufsen Beoplay EX in-ears provide better comfort and have IP57 water and perspiration resistance. They are perfect for enjoying music no matter the conditions or your current activity. We also appreciate the active noise cancelling, which ensures better phonic isolation. The Astell&Kern AK UW100 MKII earbuds stand out with their more balanced and natural sound. As a result, they should appeal more to discerning music lovers.

Astell&Kern AK UW100 MKII VS Devialet Gemini II

Firstly, the Devialet Gemini II earbuds have a more compact and ergonomic design than the Astell&Kern AK UW100 MKII, but both models are elegant and can almost be worn like jewelry. The Devialet IEMs win points for their active noise cancelling technology. To compete, the Astell&Kern AK UW100 MKII offer better passive isolation. Lastly, as for sound, the Astell&Kern AK UW100 MKII are more balanced and allow for greater customization.

Who are the Astell&Kern AK UW100 MKII for?

The Astell&Kern AK UW100 MKII True Wireless earbuds are designed for music lovers looking for high-quality wireless sound. They reveal every musical detail and are more balanced than most wireless earbuds on the market. The customizable equalizer lets users adjust the sound signature depending on their needs and preferences. Moreover, the passive isolation lets you listen to your music in noisy spaces.

Our opinion on the Astell&Kern AK UW100 MKII

For the second time, the Korean brand delivers a pair of first-rate earphones that will appeal to anyone looking for True Wireless earbuds that offer high-fidelity sound. With their balanced armature transducers, aptX Adaptive Bluetooth module and audiophile DAC, the Astell&Kern AK UW 100 MKII True Wireless earbuds are the ideal solution for high-quality wireless listening. The equalizer added to the app also enables true sound customization. While comfort could be improved, the passive isolation is highly effective.

We liked

• The balanced and natural reproduction
• The vast soundstage
• The customizable equalizer
• The passive isolation
• The aptX Adaptive compatibility

We would have liked

• For the earbuds to have been smaller
  Greater comfort