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.
Built upon an advanced Octa audio circuit architecture, the SP4000 distills 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.
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, the more powerful system is stable with fast and fluid movement.
To maximize the efficiency of the circuit and reduce heat, 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).
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.
High Driving Mode
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.
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
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 help stabilize battery voltage and effectively suppress noise, resulting in cleaner, purer sound.
Precision Sound with Any Layer HDI PCB
To minimize signal loss, 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.
Sound Design Through DAC Filters
With the SP4000, you can enjoy the fun of creating your own sound style by directly selecting various DAC filters provided by the DAC manufacturer. Design your own sound through 6 DAC filters.
4.5th Generation UI
The SP4000 features an upgraded UI that balances both functionality and emotional experience.
A&K's First Full Android OS Integration
Astell&Kern has overcome Android OS’s sampling limitation (SRC) through its proprietary customization technology, ADP (Astell&Kern Direct Path).
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.
99.9% Pure Copper Shield Can
For the first time in A&K's lineup, the SP4000 is equipped with a precision-engineered Shield Can to block various types of noise and electromagnetic interference that could affect the audio block.
6-inch 2K Display
Experience the SP4000 more conveniently and comfortably with a wide 6-inch, large-screen 2180x1080 2K display.
AK File Drop
With the new AK File Drop function in the SP4000, you can freely transfer files wirelessly through a PC, smartphone, or FTP program located on the same network
Automatic 'ReplayGain' and Uniform Volume Adjust
ReplayGain adjusts sound sources with different volumes to identical levels so you can enjoy your own playlists seamlessly.
Wireless Hi-Fi Sound via BT Sink
Enjoy playback from an external device (ie. smartphone) in high-quality using the BT Sink function.
PD 3.0 Fast Charging Supported
The SP4000 supports Qualcomm QC 3.0 fast charging, so you can charge your DAP faster and more efficiently than previous models, reaching a full charge in about 4 hours.
Crossfeed Technology
Through the use of detailed settings such as Shelf Cutoff, Shelf Gain, and Mixer Level, you can set the level of crossfeed according to your listening preferences.
Material Innovations
The SP4000 uses 904L stainless steel material that has never been attempted before in a portable audio player. Using this material has expanded its value from just a digital device to the realm of a luxury good.
Shrunken Calfskin Leather Case
The SP4000 comes with a deluxe case crafted from shrunken calf leather sourced from Perlinger in Germany, ensuring a level of style and quality that matches the quality of the device.