A&ultima portable reference with True Quad DAC architecture
Astell&Kern SP4000 combines four AK4499EX DACs with four AK4191 modulators in an Octa Audio structure designed to keep digital and analogue processing precisely separated.
It is aimed at listeners who want the top A&ultima platform without a valve output stage: compared with SP3000M it provides a larger interface, higher output voltage and a new-generation 1:1 audio architecture. Its 904L stainless-steel body, 6-inch 2K display and full Android system also make it a DAP built for intensive use with local files and streaming services.
Key features
- True Quad DAC with 4 AK4499EX and 4 AK4191 devices in a 1:1 configuration.
- PCM playback up to 32-bit/768 kHz and native DSD512.
- 3.5 mm unbalanced and 4.4 mm balanced headphone outputs, up to 8.2 Vrms.
- High Driving Mode with parallel op-amp stage for more demanding headphones.
- ESA Enhanced Signal Alignment technology to reduce group delay.
- Advanced DAR with Virtual Sound Extender for digital remastering.
- 256 GB internal storage and microSD expansion up to 1.5 TB.
- Dual-band Wi-Fi and Bluetooth 5.0 with aptX HD, LDAC and LHDC.
Octa Audio: one digital processor for each DAC
The central change from the previous generation is the Octa Audio structure. Each AK4191 feeds a single AK4499EX, avoiding signal distribution between multiple converters and improving separation throughout the audio path. The published technical performance includes a signal-to-noise ratio of up to 131 dB from the balanced output.
More drive when the headphones need it
High Driving Mode raises driving capability by using additional op-amps in parallel. This is particularly useful with dynamic or planar headphones that benefit from greater reserve, while the 4.4 mm balanced output reaches 8.2 Vrms under no-load conditions. Standard gain control remains available for very sensitive IEMs.
Full Android and direct-path streaming
SP4000 uses full Android with Google Play and Astell&Kern Direct Path, developed to bypass the sampling-rate conversion normally imposed by the Android audio path. The player can therefore serve both as a self-contained Hi-Res library and as a source for major music apps while retaining its dedicated audio processing route.
Who it is for
This is the A&ultima option for listeners prioritising completeness, output capability and direct streaming rather than the character of a valve stage. SP3000M suits those who want a more compact body, while SP4000T is the closest alternative for users who want to shape the analogue presentation through tubes.
