Astell&Kern KANN Alpha review: This digital audio player delivers the high-res goods

The KANN Alpha is the third model in Astell&Kern’s acclaimed KANN series, following the KANN (reviewed in 2018) and the KANN Cube (reviewed in 2019). These are high-end, high-res digital audio players (DAP) designed to deliver pristine audio to just about any headphone you might decide to pair it with—regardless of impedance.

The Alpha continues the KANN line’s superlative pedigree, but only a select audience will be willing to hand over $1,099 to attain its drool-worthy feature set and very high performance. This player is perfect for owners of difficult-to-drive headphones; music lovers who demand the latest advancements in wireless audio, including Bluetooth 5.0; people who demand broad high-res codec support; audiophiles who want to take full advantage of 4.4mm balanced audio support.

This review is part of TechHive’s coverage of the best mobile digital audio players,  where you’ll find reviews of competing products, plus a buyer’s guide to the features you should consider when shopping for this type of product.

Cutting-edge features, unrivaled codec support

Having reviewed Astell&Kern’s previous two KANN models, it’s clear that each model has a specific focus. Whereas the KANN Cube was geared towards the audiophile demanding no-compromise performance and balanced audio connections to high-end audio gear, the KANN Alpha seems targeted towards the audiophile who demands the latest high tech features and wireless standards.

The KANN Alpha uses USB-C for all digital connectivity and charging. That’s a welcome sight given the original KANN’s dual-personality with both micro-USB and USB-C connectors—each with different purposes. Connect the USB-C to your computer and you can use the KANN Alpha as an all-in-one headphone amp and DAC.

Theo Nicolakis / IDG

The heart of the Alpha is an ESS Sabre ES9066AS DAC. The ES9066AS is a 32-bit stereo DAC with MQA rendering. The DAC will decode MQA, FLAC, ALAC, AIFF, WAV, and every major legacy audio format, including native DSD256 decoding.

The KANN Alpha’s wireless codec support is unrivaled. The Alpha supports LDAC, MQA, aptX HD, aptX, AAC, and—of course—SBC Bluetooth codecs. The Alpha even supports MQA-CD playback when playing MQA-CD’s via Astell&Kern’s CD-Ripper.

Codec support doesn’t stop there. The Alpha’s settings menu allows you to select a preferred codec for all your wireless connections. When it comes to LDAC, you have a choice between audio quality optimization or connection quality optimization. If one of the Alpha’s onboard codecs isn’t supported by your headphones or other Bluetooth receiver, then the Alpha will switch to a mutually supported codec.

Bluetooth 5.0 is on board, giving you a huge advantage in wireless operating range, speed, low power consumption, and security features. You’ll see a theoretical maximum of 800 feet in open spaces and about 130 feet in typical indoor spaces—that’s a far cry from the 33 or so feet in Bluetooth 4.2. Likewise, Bluetooth 5.0 delivers twice the speed of Bluetooth 4.2: 2Mbps vs. 1Mbps.

Astell&Kern touts the KANN Alpha’s quad-core CPU. In my testing, Astell&Kern either needs to bump the processor’s performance or optimize the underlying operating system a bit more. While the KANN Alpha is generally responsive, there were times where the player would just lag. I couldn’t find a consistent rhyme or reason. I sometimes found myself clicking things two or three times, unsure if the player had registered my input. While the lag is nowhere near the dog-awful performance of the now defunct AK Jr, for a player in this price range, performance should be snappy and precise.

It’s worth noting that the KANN Alpha retains the rich feature set of all Astell&Kern players, including DLNA network streaming. I’ll point you to my AK70 review for a more in-depth discussion of all those features.

Introducing 4.4mm balanced audio output

The KANN Alpha sports familiar 3.5mm unbalanced and 2.5mm balanced outputs. The Alpha is the first Astell&Kern DAP to sport a 4.4mm balanced headphone connection. Astell&Kern says its 4.4mm implementation is unique and noise-free because the Alpha physically separates the 2.5mm and 4.4mm outputs using microrelays. The Alpha’s design prevents noise and interference from outputs that aren’t in use by switching them off. Smart.

Theo Nicolakis / IDG

Power and battery life

Clean power is the measure of any high-performance audio system, and the Alpha’s amplifiaction is superb. The Alpha’s internal amplifier has three gain settings—low, medium, and high—so you can match the amplifier’s output to your headphone’s impedance. Setting the amplifier to high and using the KANN’s balanced output, you’ll be able to take advantage of the Alpha’s 12Vrms output, which is the same output as the massive KANN Cube. Setting the amplifier to high will drain the battery quickly and Astell&Kern recommends connecting the USB-C charging cable if you use the amplifier in the high gain setting.

Draining the battery quickly is a relative term and will depend on several factors including the types of audio files you’re playing and volume levels you’re playing them at. Battery life is rate at 14.5 hours of continuous playback. You can get a full charge in about 3.5 hours. In real-world use, I sometimes went days without needing to recharge the KANN Alpha.

Protecting your hearing

Hearing is a precious gift. Thankfully, protecting our hearing is getting a bit easier. For the first time, an Astell&Kern DAP gave me a loudness warning. If I set the player above 50 with the 2.5mm balanced connection, or 60 with the 3.5mm output, the player warned me I could permanently damage my hearing. I had the option to defeat that warning message or enable volume limits in settings.

Doubles as an artistic statement

The KANN Alpha’s gorgeous design continues Astell&Kern’s seemingly endless play with geometric design and textures. When you buy an Astell&Kern high-res player, you’re buying a work of art as much as you are a DAP. To me, the KANN Alpha’s design is a  synthesis of the KANN Cube and elements of the SA700.

The player’s all-aluminum casing has different finishes on each side. The back sports a black, brushed-aluminum finish with the words KANN machine engraved into the player’s body. The name Astell&Kern, with model and power requirements, are laser engraved. That lettering, however, only becomes visible when you shine a light on it, much like the One Ring’s Tengwar script from the Fellowship of the Ring, which appeared only when heated in fire.

Theo Nicolakis / IDG

The player’s sides and bottom are matte-finished and untextured. This time around, Astell&Kern chose to protrude the front glass ever so slightly from the player’s body and round the glass sides and edges. The tactile experience is amazing and the rounded edges create a singular line of light that complements the player’s beveled, aluminum edge.

Astell&Kern seems to be joining the 1980s throwback party by including a ceramic black, mirrored finish along the KANN Alpha’s top. Gold circular accents around the three heapdhone inputs complement the black mirrored finish. The gold color pallet reminded me of the similar black and gold color pallet on legendary high-end audio gear from Nakamichi and Pioneer Elite.

Astell&Kern says  there is a special coating applied to the ceramic surface to prevent fingerprints and smudging, but I didn’t find it to be effective. In my hands, the KANN Alpha’s high gloss ceramic finish and front glass were far from oleophobic. They both collected fingerprints easily and at a far higher rate than my iPhone 12. I found myself wiping the high gloss finish and glass every now and then.

Ephe Nicolakis / IDG

The KANN Alpha maintains the same mesmerizing LED illumination around the player’s volume knob that I first experienced in my review of Astell&Kern’s SA700 DAP. Unlike the SA700, where the LED ring took center stage, Astell&Kern has given it a more subdued role, recessing the LED ring almost inside the player’s casing. You’ll notice it if you look at the KANN Alpha from the side, but the LED ring is largely shielded from view when you look at the player head on.

Theo Nicolakis / IDG

As with the SA700, the LED ring isn’t just a design element, it gives you a visual indication of the file format you’re playing. Red indicates you’re playing a 16-bit file; green, 24-bit; blue, 32-bit, and purple indicates DSD. If you don’t like the LED feature, you can turn it off through the settings menu. The LED temporarily changes to a red color pallet when you adjust the volume. The LED increases saturation to a light-saber red as you turn the volume louder, and it de-saturates towards a light rose color as you turn the volume down.

The LEDs worked as expected with local files and the Open APP version of Tidal, but I encountered an anomaly with Quobuz. With that service, both CD-quality and all high-res files up to 24-bit/192kHz showed only a red LED. Either Quobuz wasn’t streaming the high-res files advertised, or there’s a bug in the Quobuz app that isn’t registering properly with the Alpha.

Three rectangular buttons on the left side (in contrast to the KANN Cube, where the buttons sit below the volume knob on the right) are unmarked. By now, Astell&Kern assumes everyone knows the top button is previous track, the middle is play/pause, and the bottom is next track.

Open APP Service

A valid criticism of Astell&Kern players over the years would have rightly been the dearth of apps and supported music services. In the past, I would have been paying more careful attention to the KANN Alpha’s 64GB internal storage and 1TB micro SD card support. But now, with the introduction of Astell&Kern’s Open APP feature and support for streaming services with high-res audio files, that’s less of a pressing issue.

Astell&Kern’s Open APP lets you install just about any major streaming service onto the player. I first experienced Open App in my Astell&Kern SR15 review. As of this writing, 10 Astell&Kern players support Open APP.

Ephe Nicolakis / IDG

I have a serious love-hate conflict with Open APP. The good news about Open APP is that you can install Apple Music, Tidal, Qobuz, Amazon Music, Spotify, and a dozen more streaming services to suit your taste or current subscription. The downside is that the Open APP installation process remains clunky and requires a computer. You can indulge yourself in the step-by-step installation process here.

I’m sure you’ll agree that you shouldn’t have to go through a nine-step installation process on a $1,000+ DAP. At some point in Open APP’s evolution, Astell&Kern should pre-load all these apps into the player as “ready to install,” and then provide the end user the ability to perform an over-the-air (OTA) installation over Wi-Fi. The other approach would be to pre-install a dozen or so of the most popular and allow the end user to turn them on or off. Astell&Kern just needs to make it easier for the user to get the music services they want.

While I’m truly thankful that Astell&Kern has Open APP, it’s clunky implementation sticks out like a sore thumb against the meticulous detail A&K pays to the rest of the user experience.

Effortless, musical bliss

I used Focal Clear, Bowers & Wilkins P9 Signature, Oppo PM-2, and Beyerdynamic Amiron Home headphones with the KANN Alpha. I used a Kimber Cable Axios 2.5mm balanced cable with the Focal Clear. Though I also paired the KANN Alpha with a pair of Bowers & Wilkins PX Wireless headphones, my comments below pertain to my wired listening.

The KANN Alpha’s effortlessness is astonishing. The Alpha’s firm, unrelenting sonic grip on every single headphone was completely insane. The KANN Alpha’s control revealed ripples and textures on the classic bass lines in James Blake’s “Limit to your Love.” The Alpha articulated the details and decay of bass strings on Ingrid Michaelson’s “The Way I Am.” I noted deep, controlled, pulsating bass on Katie Melua’s “Sailing Ships from Heaven.” No matter the track, there was no smearing and no muddiness. It goes without saying that to get the most of the KANN Alpha’s bass performance, you’ll want to use closed-back headphones. The Focal Clear and Oppo PM-2 open-back headphones couldn’t deliver the deep bass performance their closed-back counterparts were capable of.

That sonic grip comes at a price: The KANN Alpha is a brutally honest customer. It won’t cuddle you or euphonize sub-par headphones. It will lay bare any shortcomings in your headphones and your source material.

Theo Nicolakis / IDG

I shook my head again and again, track after track at the attack, detail, and bass control on anything I threw at it. Music seems to emanate from a velvety black background with this player. The noise floor and channel separation are superb, allowing you to peer deeply into the music. Rebecca Pidgeon’s “Spanish Harlem,” by Chesky Records, is a reference-grade recording. It was easy to follow the subtlest decays of Ms. Pidgeon’s vocals through the KANN Alpha.

Ephe Nicolakis / IDG

In fact, the KANN Alpha’s sound is so clean and distortion-free that you’ll be tempted to bathe yourself in sound for hours. You can easily lose track of how loud you’re listening to it.

The KANN Alpha’s presentation is consistent with other ESS Sabre-based players I’ve reviewed. The presentation won’t woo you with warmth; rather, the music is clean, transparent, and detailed with airy highs and tight, controlled bass. Astell&Kern hasn’t added any artificial bumps or overemphasis.

I will note that during my review period, the KANN Alpha’s body had a tendency to get warm to quite warm. How warm will depend on your headphone’s impedance and if you’re decoding DSD and high-res files.

A grand slam

Astell&Kern’s KANN Alpha hits a grand slam—though not without a few stumbles around the bases. The Alpha earns its place among the finest high-res audio players I’ve reviewed. By any measure, the KANN Alpha is a superlative high-res DAP.

If you’re an audiophile who wants the freedom to connect any high-end headphone, you also want to connect your high-res DAP to your stand-alone setup, you might find the KANN Cube a better fit. If portability in a slimmer form factor is a higher priority, then you should add the SA700 to your short list.

But if you’re looking for a middle ground, something that can drive any headphone, fit in the palm of your hand, and deliver cutting-edge wireless audio tech, the Alpha is your ticket.

The Alpha’s gorgeous design; high-powered amplification; 40-meter wireless range with Bluetooth 5.0; unparalleled high-res wireless codec support; generous battery life; 2.5 and 4.4mm balanced audio connections; and effortless sound with dual ESS ES9068AS DACs are just the introduction to a long list of specs and features that truly make this the “Alpha” player among its peers. Its occasional sluggishness, clunky Open APP architecture, and fingerprint-prone surfaces are minor annoyances; they certainly aren’t enough to dampen my spirits about this superlative-sounding high-res DAP.