A&norma SR25 MKII: Astell&Kern unveils the second-generation model of its award-winning, ultra-portable hi-res audio player

Astell&Kern, the global leader in premium portable high-resolution audio devices, introduces the second generation model of its popular and award-winning entry-level player, the A&norma SR25 MKII. Every aspect admired about the original SR25 is retained with the new model improving on the audio performance, adding new features, such as a balanced 4.4mm headphone jack, and tweaking its already eye-catching and ultra-compact design. The A&norma SR25 MKII represents the perfect entry-point into Astell&Kern’s unrivalled world of high-resolution music playback on-the-move.

Astell&Kern A&norma SR25 MKII feature upgrades include:

  • Improved sound performance
  • 4.4mm headphone jack to deliver enhanced dynamic range, bass response, wider soundstage, clearer imaging and more detail in the audio source.
  • Replay Gain function to uniformly adjust volume playback from sound sources up to 24-bit/192 kHz.
  • AK File Drop for easier wireless file transfers.
  • BT Sink function for simpler connection of the SR25 MKII to an external Bluetooth device
  • Extra internal silver-plated shielding, first seen in the higher-end SP2000T, to protect from electromagnetic interference.
  • New, more defined volume wheel design.
  • New darker and stylish Mercury Dark Silver finish.

Even more balance and detail

This new pocket powerhouse may have a familiar look and feel but it delivers superior sound through Astell&Kern’s latest advanced audio design technology. Presenting more detail than its predecessor, the natural high-resolution sonics deliver clearly defined upper and lower ranges and a deeper, more rounded sound.

The addition of the balanced 4.4mm headphone jack, joining the 2.5mm (balanced) and 3.5mm (unbalanced) outputs, means music fans can connect an even wider variety of headphones, IEM’s and devices. The 4.4mm balanced output provides improved dynamic range and bass response, supports a wider soundstage, while capturing clear imaging and subtle details in the audio source.

As with the first-generation model, the SR25 MII handles an array of high-resolution music formats and sample rates. Support for native playback of DSD256 and 32-bit/384KHz PCM high-resolution audio, brings every music fan closer to hearing the artist’s original studio sound. Should you want to listen to your favourite hi-res music over a wireless connection, the SR25 MKII features the latest high-definition Bluetooth wireless codecs: LDAC and aptX™ HD.

Replay gain

The SR25 MKII also adds Replay Gain functionality to the mix. This automatically and uniformly adjusts volume playback from sound sources up to 24-bit/192 kHz so playlists can be enjoyed throughout without reaching for the volume.

Extra connectivity options

First introduced in the A&futura SE180 player, AK File Drop ensure easier wireless file transfers. Users can wirelessly transfer files through a PC, smartphone, or FTP program located on the same network to make music management even more convenient. Secondly, the new BT Sink function connects the SR25 MKII to an external device, such as a smartphone, via Bluetooth, enabling music to be played back in high-quality on the Astell&Kern player.

Added internal protection

Astell&Kern players apply shield cans to eliminate electromagnetic interference caused when internal components are in operation. First introduced in the higher-end A&ultima SP2000T, the SR25MKII has taken further measures by applying highly conductive, hyper-pure silver plating on the existing shield cans for extra defence against these sound performance-effecting disturbances.

Refined design

The SR25 MKII inherits the overall design identity of the original SR25 model, sporting the recognisable angled top and bottom bezel edges to give the impression the smaller inner rectangle is floating freely from the main body. The new look pattern on the side volume wheel is also more defined and tactile, drawing more attention to this area of the player. Lastly, the new darker hue of silver (Mercury D. Silver) stands apart from the original’s Moon Silver livery.

Protect your A&K player

A protective case in a choice of three eye-catching finishes is available to compliment the SR25 MKII and safeguard this premium player from the vagaries of a life on the road. Made from a soft and durable LASKINA® polyurethane fabric from Italy, this memory material offers protection against external shocks and scratches, while providing excellent grip. The fabric also mimics the texture of classic, high-end leather, for a luxurious and vibrant look, including natural leather-style creases and shine. Finishes include Denim Blue, Orange and Black.

The Astell&Kern A&norma SR25 MKII is priced £699 / $749 / €799 and is available now from and local independent dealers.

The Astell&Kern A&norma SR25 MKII case is priced £59 / $60 / €69 and is available now from and local independent dealers.


General Specifications

Model: SR25 MKII

Body Colour: Mercury Dark Silver

Body Material: Aluminium

Display: 3.6-inch HD 720 x 1280 px touch screen

Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF, MQA

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)

CPU: Quad-core

DAC: Ciruss Logic CS43198 x2 (Dual-DAC)

Decoding: Support up to 32bit / 384kHz Bit to Bit playback

Input: USB Type-C input (for charging & PC & MAC)

Outputs: Unbalanced Out (3.5mm), Balanced Out (2.5mm, only 4-pole supported / 4.4m, only 5-pole supported)

Wi-Fi: 802.11 b/g/n (2.4GHz)

Bluetooth: V4.2 (A2DP, AVRCP, Qualcomm® aptX™ HD, LDAC)

Dimensions: 2.5” (63.5mm)[W] x 4.26” (108.3mm)[H] x 0.63” (16.1mm)[D]

Weight: about 178g (6.27oz)

Firmware upgrade supported (OTA)

Operating Temperature: 0℃ ~ + 40℃ (32℉~ 104℉)

Audio performance

Frequency Response

  • ±0.014dB (Condition : 20Hz~20kHz) Unbalanced │ ±0.011dB (Condition : 20Hz~20kHz) Balanced
  • ±0.010dB (Condition : 20Hz~70kHz) Unbalanced │ ±0.012dB (Condition : 20Hz~70kHz) Balanced


  • 122dB @ 1kHz, Unbalanced
  • 124dB @ 1kHz, Balanced


  • -138dB @ 1kHz, Unbalanced
  • -144dB @ 1kHz, Balanced


  • 0.0006% @ 1kHz, Unbalanced
  • 0.0005% @ 1kHz, Balanced


  • 0.0004% 800Hz 10kHz (4:1) Unbalanced
  • 0.0003% 800Hz 10kHz (4:1) Balanced

Output Impedance

  • Unbalanced Out 3.5mm (1.2ohm)
  • Balanced Out 2.5mm (1.8ohm), 4.4mm (1.7ohm)

Clock Source

Clock Jitter: 25pS (Typ)

Reference Clock Jitter: 70ps

Storage Capacity

Built-in Memory: 64GB [NAND]

External Memory: microSD x1 (Max. 1TB)


Capacity: 3,150mAh 3.7V Li-Polymer

Charge Time: about 2.5hours (5V 2A General Charging)

Playback Time: about 20hours (Standard : FLAC, 16bit, 44.1kHz, Unbalanced, Vol.50, EQ Off, LCD Off)

Supported OS

Supported OS: Windows 7,8,10(32/64bit) MAC OS X 10.7