By now, unless you’ve been spending your time in a cave with no Internet access, you’ve heard of Astell&Kern. Although the company did not invent the portable personal music player, Astell&Kern has been a leader in portable audio ever since it introduced its first product, the AK100. Since then the maker has released a series of portable players that range from the AK Jr ($499) to the AK380 ($3499). Astell&Kern’s latest offering is the AK70 ($599), which is its least expensive player with balanced output connectivity. The AK70 also includes provisions for support (with a subscription) of Tidal, Groovers+, and MOOV streaming services, so you have your choice of either local (on the Micro SD card installed in the AK70) or, with Wi-Fi access, online music libraries.
The AK70 uses the same Cirrus Logic CS4398 DAC used in Astell&Kern’s AK100II. It can play back almost any musical file format currently available including up to 5.6MHz DSD. It recognizes and supports 384/32 PCM, but these files are internally down-sampled to 192/24 PCM during playback. The AK70 can also transfer DSD in native format through DoP, or it can convert DSD into PCM for output to portable DACs that do not support DoP.
The AK70 has two headphone outputs, a single-ended 3.5mm stereo connection and a 2.5mm balanced jack. Both have a maximum output of 2.3VRMS. Other output options include line-level analog (a full-level analog output that bypasses the volume control) and USB (so you can use the AK70 with an outboard DAC) as well as network playback via Wi-Fi. You can also use the AK70 as a stand-alone DAC via its USB connection; the limitation is that used as a DAC the AK70 only supports up to 96kHz/24-bit plyaback. For additional flexibility A&K also allows 48kHz/24-bit streaming over aptX Bluetooth HD.
Another very useful feature is “AK Connect,” which allows the AK70 to connect via a Wi-Fi network to a network attached storage (NAS) drive. When you are at home you can play any and all music contained on your NAS drive, including 192/24 PCM and 5.6 DSD. (For the record, after selecting a DSD file I did experience an initial delay of about two seconds before it began playing.)
The AK70 has one micro-smart-card slot that can support up to a 256GB card. With an internal memory of 64GB, you can max out the AK70 with 320GB of music files (some space is reserved for OS files). While that is not sufficient to carry an entire mature music library, unless you are doing a 500-day around-the-world walk-a-thon the AK70 should provide enough storage space to handle your comings and goings. When you’re at home, the amount of onboard storage becomes moot since you have access to your entire music library on your NAS via AK Connect. Although the AK70 uses an Android operating system it is not open to the point where you can add apps from the Play Store. Currently the U.S. version of the AK70 comes loaded with the aforementioned Tidal, Groovers+, and MOOV.
Ergonomics and Everyday Use
Since the development of its AK100, Astell&Kern has maintained certain signature physical design characteristics, such as a rotary, side-mounted volume knob, that have been included once again on the AK70. But unlike the AK100, where the volume knob stuck out, or the AK120 where a protective barrier beside the knob was used (similar to the kind seen on Panerai wristwatches), the AK70’s volume knob is recessed into the body of the player. To avoid “squareness” the AK70 has a slightly curved section to the right of its TFT LCD touchpad display. The AK70’s stock color is mist green, but since its original release A&K has also issued several special-edition black options in select markets. When compared to A&K’s other offerings the AK70 could very well be the most “sensible” physical design and shape. Neither too tiny nor too husky, and shirt-pocket-able, the AK70 is small enough to take on any trip, but not so miniscule that it’s easily lost.
With its 2200mAh 3.7V lithium polymer battery the AK70’s play time will vary—as it does with all portable players—based on the amount of power drain, which depends on the bit rate of the files played through it. A&K does not provide a battery-life specification, but I never ran out of juice at home. Even on a recent trip the AK70 was still going strong when I reached my destination. Accessory battery power supplies have gotten so inexpensive and ubiquitous that anyone who frequently travels should have at least one in his kit, which makes portable player (or smartphone) battery life less critical. Recharge time was under three hours from completely exhausted to full battery level.
I used the AK70 with a wide variety of headphones. With extremely sensitive in-ears such as the Empire Ears Zeus there was no continuous background hiss or noise, but when I used AK Connect I did hear a bit of low-level random noise during the silence before a track began to play. Going to the other extreme, the AK70’s single-ended output drove my pair of Beyerdynamic DT 990 600-ohm version to adequate volumes at an indicated level of 125 out of a maximum level of 150. Using a Silver Dragon adapter cable from Moon Audio, I could use the MrSpeakers Ether Flow headphones in balanced mode with an average volume setting of 110. With both of these less sensitive ’phones there was no noise in the silences before tracks began to play.
I must stress that your choice of earphones will have a far greater effect on the overall sonic character of the AK70 than the AK70’s intrinsic sound quality. Having said that, I did find the AK70 had a different sonic character than the Onkyo DP-X1. The Onkyo has a more relaxed presentation (with the same in-ears, of course) with slightly more depth, but less presence, as if you had moved back several rows at a live concert.
The two headphone pairings I returned to on a regular basis during the AK70 review period were the MrSpeakers Ether Flow ’phones and the Ultimate Ears UE 18+ Pro in-ear monitors. In both cases the AK70 was absolutely silent when it was supposed to be silent, yet had gain to spare with excellent bass extension when playing the most demanding sources. Another pairing that proved to be a particularly synergistic combination that I would recommend for an AK70 owner on an extreme budget was the KZ ZST in-ear. This $25 (available primarily from Chinese Internet vendors such as AliExpress) hybrid earphone (one balanced armature and one dynamic driver) required very little power, with normal listening settings around 75, and delivered a smooth, almost lush harmonic balance that lent itself well to brighter pop music mixes.
There is certainly no shortage of competition in portable players priced around $500. Although Astell&Kern’s AK Jr is still available, for the extra $100 the AK70 clearly delivers a better value. With the addition of balanced output capabilities, streaming, AK Connect, and USB DAC features the AK70 does more of the things that a portable DAC should do. I also prefer the AK70’s physical size and shape.
Deciding between the AK70 and the Onkyo DP-X1, whose street price is currently running around $599, is a more difficult choice. The DP-X1 has more onboard storage thanks to its dual micro-SD slots, but does not have the ability to connect with a NAS unless you add an App such as Foobar2000 from the Google Play store. With its open Android system, the Onkyo has greater flexibility than the AK70, but that can lead to compatibility issues since some third-party apps introduce more problems than they solve. The DP-X1 also supports and decodes MQA files, which could be a major advantage now that Tidal has begun streaming MQA. Size-wise I prefer the AK70’s smaller dimensions and lighter weight. In sonics, as I’ve mentioned, your preference will probably revolve around your choice in earphones. Both are excellent players and neither could by any stretch be considered a bad or wrong choice.
The Sony ZX100HN that’s currently priced at $699 offers 70 hours of battery life playing MP3 files and uses a “closed” Android system like the AK70. It does not have a balanced headphone output and was not as good a match with difficult-to-drive headphones. But it does come bundled with a dedicated pair of noise-canceling earphones which work quite effectively, and it also has Sony’s Sense-Me shuffle, which I found to be the best “random play” feature I’ve experienced.
With its previous players Astell&Kern firmly established itself as a purveyor of the finest (and most expensive) portable players available, but the company was never in the running to offer the best value for the money at entry level. But with the AK70, A&K has a player that offers more usable features and flexibility at an affordable price than any of its previous offerings. With the ability to easily handle a wide range of earphones thanks to its balanced and single-ended connections, combined with features such as AK Connect, which allows you to play back anything on your home NAS through the AK70, this player delivers more value and bang-for-the-buck than most of the current crop of players priced between $500 and $700.
If I were in the market for a portable player priced under $600, as of right now the AK70, along with the Onkyo DP-X1, would be my first choice.
Specs & Pricing
Type: Portable player with network capabilities
Display: TFT LCD
Supported formats: PCM to 384/32, DSD 2.8 and 5.6
Outputs: Analog single-ended and balanced digital
Battery life: Not listed
Memory capacity: 256K
Dimensions: 2.37″ x 3.81″ x 0.51″
Weight: 4.6 oz.
39 Peters Canyon Rd.
Irvine, CA 92606
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