Built on Legacy, Evolving Perfection
The A&ultima SP4000 is Astell&Kern’s newest flagship digital audio player, the result of three years of relentless research and innovation following the development of the SP3000.

As part of the A&ultima series—Astell&Kern’s flagship lineup combining cutting-edge technology and top-tier specifications—the SP4000 surpasses the boundaries set by the SP3000, once regarded as the ultimate reference.

Built upon an advanced Octa audio circuit architecture, the SP4000 distils the purest essence of audio engineering, delivering a sound experience unlike anything before it—refined, powerful, and remarkably close to perfection. Discover the SP4000 and experience sound on an entirely new level.

Enhanced Signal Processing Capabilities with Octa Audio Circuit Architecture
In the SP3000, the digital-to-analog signal processing structure was separated in a 1:2 ratio. With the SP4000, it has evolved into a 1:1 architecture.
This new structure, where one AK4191 digital processor is paired with one AK4499EX DAC, allows digital signals to be delivered precisely to a single DAC without the need to distribute noise, enabling improved signal separation and processing.

Through continuous research and innovation in circuit technology, the SP4000 successfully implements a true Quad DAC—a feat previously considered impossible due to noise and other issues. As a result, the SP4000 achieves an impressive SNR (Signal-to-Noise Ratio) of 131dB, on par with the independent dual audio circuit of its predecessor.

Supports High Driving Mode for Premium Sound Performance
The SP4000 features twice as many OPAMPs arranged in parallel compared to its predecessor, delivering richer and more detailed sound. High Driving Mode provides powerful and stable output—much like a four-wheel-drive vehicle confidently navigating rough terrain. It’s designed to reproduce even the most delicate sonic details with precision, allowing you to enjoy deeper, clearer, and more immersive music.

Minimized group delay with proprietary ESA (Enhanced Signal Alignment) technology
The SP4000 features proprietary ESA (Enhanced Signal Alignment) technology, which significantly improves one of audio’s long-standing challenges—group delay. ESA technology aligns frequency signals to arrive more uniformly, minimizing frequency distortion and dramatically enhancing sound clarity and purity.

Top-Tier Noise Suppression (Ultra Low Noise LDO Regulator)
The SP4000 features a newly implemented LDO (Low Dropout) Regulator in its power supply, which reduces noise by up to 97% compared to previous models. LDO Regulators are high-performance components typically used in precision medical devices and 5G communication equipment. They help stabilize battery voltage and effectively suppress noise, resulting in cleaner, purer sound.

Precision Sound with Any Layer HDI PCB
To achieve the highest sound quality, the SP4000 incorporates top-tier Any Layer HDI (High-Density Interconnect) PCB technology. Commonly used in smartphones and high-performance electronic devices, this advanced circuit board allows for the precise design of complex circuitry within a compact space. It minimizes signal loss, enabling the delivery of a more refined and detailed sound.

Astell&Kern’s First-Ever Full Android OS Integration
Astell&Kern has overcome Android OS’s sampling limitation (SRC) through its proprietary customization technology, ADP (Astell&Kern Direct Path). This allows for bit-perfect, lossless playback even in streaming environments, ensuring the highest possible sound quality during music listening.

In response to the growing shift toward streaming-based music consumption, Astell&Kern has integrated full Android OS for the first time.
The SP4000 not only delivers flagship-level audio quality but also offers enhanced convenience, marking its evolution into a highly refined next-generation digital audio player.

First-Ever Implementation of Advanced DAR by Astell&Kern
The SP4000 introduces Advanced DAR, Astell&Kern’s second-generation DAR (Digital Audio Remaster) technology, delivering sound that is even more natural and refined. Rather than sending the audio file directly to the DAR engine, the SP4000 first uses VSE (Virtual Sound Extender) to virtually restore lost harmonics, enhancing the sound quality at the initial stage.

Then, the advanced DAR engine performs a second-stage upsampling process with greater precision and completeness. This two-step approach allows listeners to enjoy a deeper, more immersive sound that comes closer than ever to the original recording.

Drive Your Music, Latest Snapdragon Octa-Core CPU for the Newest Flagship Device
A&ultima SP4000 is equipped with a Snapdragon 6125 Octa-core processor, so you can enjoy the overwhelming sound, faster system response and a redesigned generation user interface that moves comfortably and smoothly.

Featuring a high-performance CPU and improved 8GB of DDR4 memory, which is twice the amount commonly used, the more powerful system is stable with fast and fluid movement.

The CPU, memory and wireless communication parts are configured as one module, with the digital circuit parts arranged in the same area creating a single system on a chip (SoC). This maximizes the efficiency of the overall circuit configuration by providing more audio-only circuit space as well as reducing heat and noise from digital circuits.

Enhanced 4.5th-Generation UI That Blends Function and Emotion
The SP4000 features an upgraded UI that balances both functionality and emotional experience. The main screen includes an immersive animation where an LP appears to slide in and out as you swipe through albums—turning the act of choosing music into a visually engaging and tactile experience.
The interface retains Astell&Kern’s signature Crimson theme, reflecting the brand’s identity and capturing its distinct emotional sensibility in a refined, modern design.

Premium Shrunken Calf Leather Case from Germany’s Finest Leather House
The SP4000 is packaged with a premium leather case crafted from Shrunken Calf by Perlinger, Germany’s world-renowned leather house. Founded in 1864 and spanning five generations of craftsmanship, Perlinger supplies the finest leather to luxury brands across the globe—blending time-honored tradition with modern techniques.

The Shrunken Calf leather used in the case is made from the soft, delicate hide of calves under one year old. It is processed using a chrome tanning method to preserve its natural texture, then uniquely shrunk using special agents—not heat—to retain its organic grain and wrinkles.

Following an aniline dyeing process, Perlinger’s proprietary pigments are added to achieve a deep, vibrant color. Their advanced anti-aging treatment ensures that this richness lasts over time, complementing the SP4000 with a leather case that embodies lasting beauty, durability, and luxury.

- Enhanced signal processing capabilities with Octa audio circuit architecture
- Supports High Driving Mode for delivering premium sound quality
- Minimizes group delay with proprietary ESA (Enhanced Signal Alignment) technology
- Ultra Low Noise LDO Regulator for top-tier noise suppression
- Precision sound achieved with Any Layer Type PCB
- Equipped with a 99.9% Pure Copper Shield Can
- First Astell&Kern Device to Support Full Android OS
- First Astell&Kern Device to Feature Advanced DAR Technology
- Features 4.5th generation UI, combining functionality and emotional design

Model: SP4000 (PPF51)
Body Color:Silver
Body Material: Stainless Steel 904L
Display: 6 inch 2K (2160 x 1080) touch screen
Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF
Sample Rate:

PCM: 8kHz ~ 768kHz (8/16/24/32 bits per Sample)

DSD Native:
• DSD64 (1bit 2.8MHz), Stereo
• DSD128 (1bit 5.6MHz), Stereo
• DSD256 (1bit 11.2MHz), Stereo
• DSD512 (1bit 22.4MHz), Stereo
Output Level:

Unbalanced: 4.1 Vrms (No Load)

Balanced: 8.2 Vrms (No Load)
CPU: Octa-core
DAC: AKM4191 x4 + AKM4499EX x4 (Real Quad DAC)
Decoding Support: Up to 32bit / 768kHz Bit to Bit playback
Input: USB Type-C (charging & PC/MAC connection)

Outputs:
Unbalanced Out: 3.5mm
Optical Out: 3.5mm
Balanced Out: 4.4mm (only 5-pole supported)
Wi-Fi: 802.11 a/b/g/n/ac (2.4/5GHz)
Bluetooth: V5.0 (A2DP, AVRCP, Qualcomm® aptX™ HD, LDAC, LHDC, SBC, AAC)
Dimensions: 3.34” (85mm) [W] x 5.89” (149.8mm) [H] x 0.76” (19.5mm) [D]
Weight: About 21.7oz (615g)
Feature Enhancements: Firmware upgrade supported (OTA)
Operating Temperature: 0℃ ~ +40℃ (32℉ ~ 104℉)

Orders ship Sunday through Friday from our offices in Dubai, UAE.

In-stock products typically ship within 48 hours and should be expected to arrive in 3-4 business days. Orders outside of the UAE should be expected to arrive in 5-7 business days.

Pre-order and backorder products will state the approximate delivery timeline beside the Add To Cart button.

If you would like to place a custom order, chat with our specialists for a guided shopping experience. Once your order has been placed, a timeline will be provided depending on your order details.

- Free delivery within the UAE
- Shipping charges will be calculated upon checkout for orders outside of the UAE (Bahrain, Oman, Kuwait, Saudi Arabia & Qatar).
- Taxes and duties are calculated according to the applicable laws of the state or country an item is shipped to and are the customer's responsibility.

For additional information on shipping and our exchange & return policy visit our help center.

Installation charges are applicable and can be paid upon delivery for our clients based in Dubai.

- Installation Charges: AED 450 Per Hour
- Speaker Cables: AED 32 Per Meter
- Trunking: AED 10 Per Meter

For clients based outside of the UAE, please contact our specialists and we will share an estimate based on your requirements.