The absolute pinnacle of portable audio
The Astell&Kern A&ultima SP4000 represents the new technological pinnacle of the Korean brand's high-end digital player line. A direct evolution of the renowned SP3000, this model introduces radical innovations in terms of architecture, performance and sonic refinement , redefining what a Digital Audio Player can offer.
Inside beats a dual AKM AK4499EX DAC paired with next-generation AK4191EQ modulators , configured according to the Dual Audio Circuit Architecture that isolates the balanced and unbalanced paths to achieve an unprecedented signal-to-noise ratio . Processing is entrusted to the powerful Qualcomm Snapdragon 6125 Octa-Core , with 8 GB of DDR4 RAM for a smooth and immediate response even in the longest sessions.
The mirror-polished 904L stainless steel body reflects Astell&Kern's heritage of craftsmanship, while the new Crimson UI ensures a modern and intuitive user experience. Every detail of the SP4000 has been designed to deliver unparalleled fidelity, dynamics, and musicality , positioning it as the absolute reference in the world of portable hi-res players.
Dual performance, realistic sound and unlimited power
Thanks to the new Dual Audio Circuit Architecture II , the Astell&Kern SP4000 completely separates the circuitry for balanced and unbalanced signals, minimizing crosstalk and distortion. The integration of the latest-generation AK4499EX DACs enables playback of up to PCM 1536 kHz/32-bit and native DSD1024 , with unique digital precision and analog naturalness.
The SP4000 also introduces Darlington Current Conveyor (DCC) technology , developed in-house by Astell&Kern to offer more accurate current control while increasing output power and signal stability. The result is a more transparent sound, rich in micro-detail and with impressive dynamics .
The completely redesigned internal amplification is capable of driving even the most demanding headphones thanks to the 4.4 mm and 2.5 mm balanced outputs and 3.5 mm unbalanced output , all with almost imperceptible background noise. The interface supports the main Hi-Res streaming platforms (Tidal, Qobuz, Apple Music, Amazon Music HD) and features Bluetooth 5.0 with LDAC and aptX™ HD , as well as dual-band Wi-Fi for updates and direct connections.
With 256GB of internal memory , expandable via microSD up to 1TB , and a 5,050mAh battery that provides up to 10 hours of battery life, the SP4000 offers a perfect balance between power, portability and sonic purity , maintaining Astell&Kern's refined and iconic aesthetic philosophy.
Technical features
| Characteristic
|
Detail |
| Model
|
Astell&Kern A&ultima SP4000 |
| Processor
|
Qualcomm Snapdragon 6125 Octa-Core |
| RAM memory
|
8 GB DDR4 |
| Internal memory |
256 GB NAND |
| Memory expansion
|
microSD up to 1 TB |
| DAC
|
Dual AK4499EX + Dual AK4191EQ |
| Audio architecture
|
Dual Audio Circuit Architecture II |
| Format support
|
PCM up to 1536 kHz / 32 bit, DSD native up to DSD1024, MQA |
| Audio outputs
|
3.5mm unbalanced, 2.5mm and 4.4mm balanced |
| Signal-to-noise ratio
|
129 dB (balanced) |
| THD+N
|
0.0002% |
| Connectivity
|
USB-C, Dual Band Wi-Fi, Bluetooth 5.0 (aptX™ HD, LDAC) |
| Display
|
5.5" Full HD touchscreen (1920×1080) |
| Drums
|
5,050 mAh Li-Polymer, QC3.0 fast charging |
| Autonomy
|
Up to 10 hours |
| Materials
|
Polished 904L stainless steel |
| Weight
|
482 g |
| Dimensions (W×H×D)
|
82 × 141 × 18 mm |
| Operating system
|
Android-based with Crimson UI |
| Additional functions
|
USB DAC mode, ReplayGain, Advanced EQ, Desktop DAC mode |
| Available color
|
Silver (904L steel) |