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Astell&Kern A&norma SR25 portable digital audio player (Updated)
4.6Overall Score
Name: Astell&Kern A&norma SR25 portable digital audio player
Price (RRP): $1,199
Manufacturer: Astell&Kern

(UPDATE: The Australian distributor of Astell&Kern products has advised me that you can install additional apps on the SR25. But you do that by manually downloading *.apk Android application files. Further, the version of TIDAL pre-installed on the SR25, but it can be updated in this way. I’ve editing this review to reflect this information.)

Long before the Astell&Kern A&norma SR25 there was the iPod. Indeed, let’s go back to 2004. A South Korean company called iRiver had been the world leader in portable digital music player sales for some time. But the Apple iPod, first released three years earlier, caught up and surpassed iRiver’s sales. Within three years the iPod was responsible for more than 40% of Apple’s revenue.

Now the classic iPod is long-since gone and the iOS-based iPod Touch is a tiny bit of Apple’s business. But iRiver lives on in Australia in the form of its wholly-owned subsidiary, Astell&Kern, which specialises in the high-end side of portable audio. Its latest digital audio player is the Astell&Kern A&norma SR25.

Physical features of the Astell&Kern &norma SR25

The iPod Touch is based on iOS. The SR25 is, like Astell&Kern’s other players, based on Android. But it’s a skinned Android. Unlike some other Android-based music players, you can’t install other music players from the Play Store. You have only what’s provided out of the box (plus anything A&K decides to include in a firmware update). It turns out that you can install additional apps, including such apps as Spotify, Apple Music, Amazon Music, Foobar2000, Soundcloud and many more. But you do that by downloading their *.apk Android application file from a safe site and installing it. I’ll return to this.

What is provided out of the box is pretty impressive. First, for a portable player it’s quite substantial. A&K hasn’t gone for slim and light, but solid and fancy. The body is created from a block of aluminium with 5-axis machining. The front and back are glass. The front is largely constituted by a touch screen. The SR25 comes with four screen protectors in the box. Protective leather cases in various colours are available for $109.

The display has a 3.6-inch – 91mm – diagonal display and a resolution of 720 pixels across by 1,280 pixels vertically. A large rotary volume control dominates the right side near the top. On the left side are forwards skip, backwards skip and play/pause buttons. The top has a power button along with the headphone outputs. One is a standard 3.5mm socket while the other is for 2.5mm balanced headphone connections.

Regular headphones have three wires – left and right signal wires and a common return – and are not necessarily electrically shielded. Balanced headphones have separate return wires for each channel and are often shielded. Proper balanced headphone amplifiers use a “push-pull” configuration to drive the headphones. Audiophiles tend to be keen on balanced headphone systems. I don’t have suitable headphones, so I stuck with the 3.5mm output.


SR25 capacity

At the bottom is a USB Type-C socket and for charging the unit and accessing its storage. It uses MTP – the Media Transfer  Protocol. The internal storage is 64GB of which around 53GB is available for music storage. Not enough? Also at the bottom is a microSD card slot. According to the specifications, it supports SD cards up to 1TB in size. I used a 256GB card with no problems. You can also plug more storage into the USB-C socket.

There are already six high resolution music files on the internal storage as samplers, consuming 830MB. Two are FLAC format (96kHz and 176.4kHz), two are DSD and two are MQA encoded. That last stands for Master Quality Authenticated, a Meridian-developed system for both certifying the quality of the recording and packing high resolution music into standard resolution file sizes.

Copying a large file to the internal memory of the SR25 proceeded at around 40MB/s. Copying that file back out only ran at 17MB/s. The slow download speed doesn’t matter since there’s little reason to copy from the unit back to your computer. Because it uses MTP, if you have a Mac you’ll need to install Google’s Android File Transfer app on the computer.

The SR25 will play pretty much every commonly available file format, including high resolution ones. Specifically: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF and MQA. And it supports PCM-based formats of up to 32 bits and 384kHz sampling along with Direct Stream Digital in DSD64, DSD128 and DSD256 forms.

It also includes apps to play Deezer and TIDAL. And “V-Link” which gives access to the likes of YouTube. I’ll stick with my phone for YouTube, given the small screen.


Other connections

The SR25 includes Wi-Fi, of course, otherwise it wouldn’t be able to provide those streaming services. It also updates its firmware that way. And while for the best quality you’re going to be using wired headphones, it does also support Bluetooth. And for best quality via that channel it offers both the aptX HD and LDAC codecs – assuming your headphones supports one or the other. aptX HD is backwards compatible with regular aptX.

Buried in the settings menu I came across something intriguing: a CD ripping function. Turns out that A&K sells a CD drive which you can plug in and rip directly to the SR25 in your choice of format, including FLAC (Free Lossless Audio Codec – the most popular lossless compression system for music out there). If the player is connected to Wi-Fi, it will populate the ID3 tags with data from the Gracenote online CD database. You can also play CDs.

I tried a third-party USB drive … no go. The AK CD Ripper Gen 2 costs $699.