Astell & Kern SR25
The SR25 turns portable listening into a rich, transparent experience, pairing natural tone with remarkable low-level detail and a black-quiet soundstage. Its 2.5mm balanced output opens up dynamics, separation and scale, while native DSD256, LDAC and 21-hour battery life make it an exceptionally capable hi-res companion. What Hi-Fi? found it notably expressive at its level.
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Deliciously Crispy
Sound Quality
95/100
Build Quality
88/100
Features Usability
92/100
Value for Money
94/100
Pros
Exceptional transparency, microdetail and natural, engaging musicality.
Balanced output delivers a larger, more precise and more dynamic soundstage.
Broad hi-res format support, responsive software and class-leading 21-hour battery life.
Cons
Amplifier power is limited with inefficient planar or medium-efficiency, high-impedance headphones at high volumes.
Single-ended listening is comparatively more intimate, with slightly fuzzier imaging than balanced output.
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What Reviewers Are Saying
SOUND QUALITY PERFORMANCE 95/100
Reviewers describe an unusually polished portable presentation: rich and smooth in tone, highly transparent, dynamically alert, and notably spacious through the balanced output. Its main practical sonic limitation is power with medium-efficiency or high-impedance headphones; the single-ended output is also said to be comparatively intimate, with slightly fuzzier imaging.
Tonal Balance Musicality
95/100
Hi-Fi Choice calls the presentation richer, smoother and easier to hear into, while What Hi-Fi praises its rich, smooth and detailed character. Positive Feedback heard natural, organic tone and texture, extended but never harsh highs, and deep, taut bass—particularly from the balanced output.
Resolution Detail
96/100
Detail retrieval is a recurring strength. Hi-Fi Choice praises its ability to expose subtle technique and ambient cues, HomeTheaterHifi heard tiny recording details such as breathing and music stands moving, and What Hi-Fi found more intricacy, space and information than its predecessor.
Digital Performance
95/100
The SR25 is praised for a black-quiet, vanishingly low-noise background and clean operation without clicks or pops during file or source changes. The Ear also reports seamless switching between hi-res PCM and DSD without glitches or lag, while reviewers found broad format support and native high-resolution playback well executed.
FEATURES USABILITY PERFORMANCE 92/100
This is a notably flexible portable source, combining broad file support, streaming-app access, wireless playback, balanced and single-ended outputs, and USB DAC capability. Software control is generally well received, though the compact screen and unconventional form factor require some acclimatisation.
Streaming Software
90/100
HomeTheaterHifi says the Android implementation stays out of the way while adding useful search and access to services including Spotify, Amazon Music and Idagio; it also identifies Roon client use at home. The Ear highlights Open APP downloads for Deezer, Qobuz and Tidal, plus A&K Connect playback from a computer or NAS, although its interface is not as immediately foolproof as a phone-sized touchscreen.
Features Connectivity
95/100
The SR25 offers extensive practical flexibility: Wi-Fi, Bluetooth with LDAC and aptX HD, MQA support, microSD expansion, gapless playback, EQ, and wide format compatibility. Both 3.5mm single-ended and 2.5mm balanced outputs are provided, while USB-C can operate as a computer DAC or send digital audio to an external DAC.
Assessments of Build Quality, Usability, and Overall Propositions.
Build Quality
88/100
The aluminium chassis, enlarged high-resolution screen and protected knurled volume control earn praise for their attractive, carefully considered execution. However, HomeTheaterHifi found the build merely fine rather than deluxe, specifically noting the absence of damping; navigation is improved over the earlier model but less foolproof than a modern smartphone.
Value for Money
94/100
At $699, HomeTheaterHifi does not call it a bargain-priced device, but considers it competitive with more expensive players, including models from Astell & Kern itself. Hi-Fi Choice says buyers will struggle to find better, while The Ear suggests few rivals at the price can match its open delivery; What Hi-Fi also characterises it as reasonably affordable.
Reviews & Sources
Professional reviews and sources for this product's Watt'n Potatoes analysis.
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Specifications
- Model
- SR25
- Body Color
- Moon Silver, Onyx Black
- Body Material
- Aluminum
- Display
- 3.6inch WVGA (720 x 1,280) TFT LCD
- Supported Audio Formats
- WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF, MQA
- MQA playback
- Services(Tidal Masters), Local files, External USB, MQA-CD(ripped)
- 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 2.0Vrms / Balanced 4.0Vrms (Condition No Load)
- CPU
- Quad-Core
- DAC
- Cirrus Logic CS43198 x2 (Dual DAC)
- Decoding
- Support up to 32bit / 384kHz Bit-to-Bit Playback
- Input
- USB Type-C input (for PC & MAC)
- Outputs
- Unbalanced Out (3.5mm) / Balanced Out (2.5mm, only 4-pole supported)
- Wi-Fi
- 802.11 b/g/n (2.4GHz)
- Bluetooth
- V4.2 (A2DP, AVRCP, aptXTM HD, LDAC)
- Dimensions
- 2.5 ”(63.5 mm) [W] x 4.26 ”(108.3 mm) [H] x 0.63 ”(16.1 mm) [D]
- Weight
- about 6.27 oz (about 178 g)
- Feature Enhancements
- Firmware upgrades supported (OTA)
- Frequency Response
- ±0.014dB (Condition: 20Hz~20kHz) Unbalanced / ±0.011dB (Condition: 20Hz~20kHz) Balanced ±0.10dB (Condition: 20Hz~70kHz) Unbalanced / ±0.12dB (Condition: 20Hz~70kHz) Balanced
- Signal to Noise Ratio
- 122dB @ 1kHz, Unbalanced / 123dB @ 1kHz, Balanced
- Crosstalk
- -138dB @ 1kHz, Unbalanced / -144dB @ 1kHz, Balanced
- THD+N
- 0.0007% @ 1kHz, Unbalanced / 0.0008% @ 1kHz, Balanced
- IMD SMPTE
- 0.0004% 800Hz 10kHz(4:1) Unbalanced / 0.0003% 800Hz 10kHz(4:1) Balanced
- Output Impedance
- Unbalanced Out 3.5mm (1.8ohm) / Balanced out 2.5mm (1.6ohm)
- Clock Jitter
- 25ps(Typ)
- Reference Clock Jitter
- 200 Femto Seconds
- Capacity
- 3,150mAh 3.7V Li-Polymer Battery
- Continuous Playback Time
- About 21 hours (Standard - MUSIC: FLAC, 16-bit/44.1kHz, Unbalance, Volume 50, EQ OFF, LCD OFF)
- Charge Time
- About 2.5 hours (Standard - 5V/2A Charging)
- Built-in Memory
- 64GB [NAND]
- External Memory
- microSD (Max. 1TB) x1
- Supported OS
- Windows 7,8,10 (32/64bit), MAC OS X 10.7 and up
- Specification
- - Audio was NOT muted during the measurement. - The image/specification may be changed without notice to improve product performance and quality.
Manufacturer's Description — Astell & Kern
The SR25 is the second model in the Astell&Kern A&norma standard line.
Beginning with the AK70, Astell&Kern's goal was to bring high resolution audio and the
Astell&Kern sound to more music lovers. This goal continued with the successor to the AK70, the
A&norma SR15, and now evolves further as the SR25, a premium product that fully embraces
Astell&Kern's philosophy and technology, now available to the masses. The SR25 is the latest
answer to our never-ending question of "How do we get closer to the original sound the artist
intended?" The SR25 improves on the SR15 by:
The essence of Astell&Kern's philosophy that sound quality is never compromised is exemplified
in the SR25, which expresses every musical detail and bit-perfect playback as only Astell&Kern
can.
- Adding a new, faster Quad-Core CPU paired with the Dual Cirrus Logic CS43198 Master Hi-Fi level DAC, first used on the SR15
- Native playback support for DSD256
- A new class-leading performance mode for ultra-high quality playback without compromise
- Newly designed circuitry to improve sound quality enhancements
- Addition of Bluetooth LDAC codec to give users more options for higher quality wireless sound
Performance Mode for Ultra High Resolution Sound
The SR25 supports native DSD256 and 32bit/384kHz audio for the first time in an Astell&Kern standard product and boasts performance that cannot be compared with other competitors' products.
The SR25, which is smaller than other players, has been developed to achieve stable, ultra-high
resolution sound.
We have developed a new Performance Mode with the SR25 that automatically
optimizes and sets the memory mode in the system according to the data size of the source being
played.
As the resolution of the sound source increases, it is necessary to process a large amount of data rapidly. If this part is not optimized, sound breakup may occur. To prevent this, the SR25 uses the new Performance Mode to adjust and optimize the system in order to produce near perfect sound quality when playing back high resolution audio.
Experience ultra-high resolution with the SR25's Performance Mode, which reproduces even the smallest, minute details of the original recording the artist was looking for, without compromise.
32-bit bit-to-bit Playback by the SR25
32-bit Playback by Other Products
Perfect Circuit Design for the Highest Sound Quality
Proper playback of DSD256 and 32bit/384kHz digital audio requires a high-performance CPU and
fast memory speed, along with an audio path suitable for high-speed signal processing.
Optimizing the length of the audio path is a very important part, as failing to properly do
so can create a time delay between the signals resulting in sound abnormalities.
With the SR25, the Astell&Kern team developed a completely different PCB design from the
existing SR15 to process the high speed signals where required, resulting in audio path
lengths that are the same, allowing for super-high resolution sound without any delay.
Furthermore, newly designed audio patterns and power circuits for distortion-free signal
transmission and noise rejection are applied to each channel.
The result is an Ultra Low Noise Filter that allows you experience Astell&Kern's flawless
sound, with Zero Noise, on the SR25.
No Compromise on Sound, Even When Connected Wirelessly
In addition to 24-bit music playback via aptXTM HD Bluetooth as in
previous Astell&Kern players, the SR25 adds LDAC support to give users more options to listen to
high resolution audio wirelessly.
Bluetooth connection conditions between the two devices may vary
depending on device and environment.
Astell&Kern's Exclusive Metalworking Technology
Astell&Kern products are often compared to art sculptures, with colorful faces and angles
not found in other products. This precise design work is based on Astell&Kern's long
accumulated know-how and highly precise metalworking technology.
In order to produce this unique style Astell&Kern is famous for, 5-axis machining is
performed instead of traditional 3-axis machining used in general machining. All metal must
be processed at once without interruption. In addition to 5-axis machining, Astell&Kern has
perfected it's crafting of metal through thousands of hours of trial and error. Only after
mastering these techniques that Astell&Kern has developed, can the beauty of the metal shine
through.
The vibration-free processing machines used by Astell&Kern are the same ones used by
expensive Swiss luxury watch manufacturers. This is reflected in the crafting of the volume
wheel which is processed precisely like the crown of a luxury watch for the best operating
feel. Astell&Kern products are designed to achieve perfect integration at whatever angle you
look at it in your hands.
The Aluminum body on the SR25 provides maximum sound quality, while suppressing noise as
much as possible. The use of laser ground extension technology gives you the best sound
possible, without interference or distortion.
Astell&Kern combines these small parts to make a big difference in the quality of our
products that no other manufacturer can match.
Latest System Optimization for a Better User Experience
The SR25 firmware is based on Android 9.0, which adds a number of behind the scene features and
upgrades to provide more stable operation over previous versions of Android OS. The use of
Android 9.0 ensures the most popular music streaming apps installed via Open APP will be fully
compatible with your Astell&Kern player now and with future app updates.
Astell&Kern customizes Android to provide a fully optimized system and user interface, designed
to give users a smooth, fluid musical playback experience.
DESIGN
The new design of A&norma SR25 incorporates drastic changes without losing
the balance between an optimal user experience, looks and keeping the
A&norma design identity. The harmonious combination of these various design
aspects symbolize the rhythmic feel and freedom of music.
On the back, the bold oblique cut surface of the rear glass meets the triangular
shapes that surround the volume wheel. The patterns of the rear glass
beautifully express the spreading of light when it is reflected off the surface.
The rhythmic pattern on the rear glass will change as light is reflected at
different angles.
The new SR25 is ideal for one-handed operation and is a perfect fit no matter
which hand you choose to hold it in. The angle of the front screen and extra
space around it gives you the perfect grip when it's held.
The player features layers of various sized rectangular surfaces with added
angles to invoke the sense of pulsating musical rhythm from its design.
Precisely milled cuts resemble various reflections of light and create a depth
of space around the volume wheel that further emphasizes the bold light reflections
that are created at different angles of view on the entire player.
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- Addicted to Audio — online and in-store — Epping, Victoria, Australia (website)
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- ALAIN CHOUKROUN — online and in-store — Paris, Île-de-France, France (website)
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- Audio 46 — online and in-store — New York, New York, United States (website)
- Audio Advice — online and in-store — Raleigh, North Carolina, United States (website)
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