Description
For audiophiles who demand uncompromising reference-grade sound in a portable form, the Astell & Kern A&ultima SP4000 Silver delivers flagship performance built around a true Quad DAC architecture. Crafted from 904L stainless steel—the same alloy trusted by luxury watchmakers—the SP4000 combines precision engineering with a striking geometric design that feels as much a luxury object as a music player.
Powered by four AK4191EQ digital processors paired 1:1 with four AK4499EX DACs, the SP4000 achieves a 131 dB signal-to-noise ratio and 8.2 Vrms balanced output through High Driving Mode. Astell&Kern's proprietary ESA (Enhanced Signal Alignment) technology minimizes group delay, while the Ultra Low Noise LDO Regulator and 99.9% pure copper Shield Can work together to suppress electromagnetic interference for a cleaner, more detailed sound. The first Astell&Kern DAP to run full Android OS with Google Play Store access, it also introduces Advanced DAR with VSE for enhanced audio restoration.
With a 6-inch 2K touchscreen, 256 GB internal storage expandable to 1.5 TB via microSD, dual-band Wi-Fi, Bluetooth 5.0 (aptX Adaptive, LDAC), and Roon Ready certification, the SP4000 bridges lossless local playback and high-resolution streaming with equal authority.
Demo unit; may show light signs of handling. Contact us for photos and details.
Specifications
| DAC Configuration | True Quad DAC: 4× AK4191EQ + 4× AK4499EX (1:1 architecture) |
| Signal-to-Noise Ratio | 131 dB @ 1 kHz (Balanced) |
| THD+N | 0.0003% |
| Balanced Output | 8.2 Vrms (High Driving Mode) |
| Unbalanced Output | 4.1 Vrms |
| Output Impedance | 1.7 Ω |
| Display | 6-inch 2K touch (2160 × 1080) |
| Processor | Snapdragon 6125 Octa-core CPU |
| Memory | 8 GB DDR4 |
| Internal Storage | 256 GB NAND |
| External Storage | microSD up to 1.5 TB |
| Battery | 6,780 mAh Li-Polymer; ~10 h playback; PD 3.0 fast charge |
| Weight | 615 g (21.7 oz) |
| Dimensions | 85 × 149.8 × 19.5 mm |
| Chassis | 904L stainless steel |
| Shield Can | 99.9% pure copper |
| PCB | Any Layer HDI |
| Signal Alignment | ESA (Enhanced Signal Alignment), 200 fS reference clock |
| Noise Suppression | Ultra Low Noise LDO Regulator (up to 97% reduction) |
| Audio Outputs | 3.5 mm SE; 4.4 mm balanced |
| Bluetooth | 5.0 with aptX Adaptive and LDAC |
| Wi-Fi | Dual-band 2.4 / 5 GHz |
| OS | Full Android with Google Play Store; ADP (Astell&Kern Direct Path) |
| Audio Processing | Advanced DAR with VSE; 6 DAC filters |
| Roon | Roon Ready and Roon Tested |
| Included Accessories | Perlinger Shrunken Calf leather case; USB-C cable; documentation |
