Astell&Kern A&ultima SP4000 – The New Standard in Portable High-End Audio

With the A&ultima SP4000, Astell&Kern once again redefines what’s possible in the realm of portable audio. Three years after the landmark SP3000, this flagship digital audio player represents the pinnacle of innovation, craftsmanship, and sonic fidelity—designed to satisfy even the most demanding audiophiles.

Revolutionary Octa Audio Architecture

At the core of the SP4000 lies a fully reengineered signal path, built on a true quad-DAC configuration: two AK4191 digital processors paired with two AK4499EX DACs. This 1:1 ratio eliminates traditional signal-splitting issues and ensures maximum clarity and channel separation. By independently handling digital modulation and analog conversion, the SP4000 delivers an immersive, lifelike soundstage with unmatched detail and purity.

High Driving Mode – Authority Without Noise

Power meets precision in the SP4000’s new High Driving Mode. Through a parallel OPAMP layout, it increases output capability while keeping the noise floor ultra-low. The result? A bold, confident sound capable of effortlessly powering even the most demanding headphones—without sacrificing nuance or emotion.

ESA Technology – Timing Perfected

Astell&Kern’s Enhanced Signal Alignment (ESA) technology tackles the age-old issue of group delay. All frequencies arrive in sync, ensuring pinpoint timing, superior imaging, and a more coherent, lifelike presentation. It’s a breakthrough that enhances every genre—especially acoustic, orchestral, and live recordings.

Ultra Low Noise Power Regulation

To support such pristine signal processing, the SP4000 incorporates a custom Ultra-Low-Noise LDO Regulator, adapted from high-end medical and 5G technology. This component reduces power-related noise by up to 97% compared to previous models, ensuring clean power delivery and an ultra-quiet background for your music to shine through.

Digitally Refined, Emotionally Real – DAR & VSE

The second generation of Digital Audio Remastering (DAR) debuts in the SP4000, working alongside the new Virtual Sound Extender (VSE). VSE restores lost harmonics and warmth, while DAR performs high-precision upsampling. Together, they create a listening experience that’s natural, emotionally resonant, and true to the original performance.

Bit-Perfect Streaming with Full Android Experience

For the first time, an Astell&Kern player features Google Play Store support, offering complete freedom over your streaming apps. Thanks to A&K’s Direct Path (ADP) technology, the SP4000 bypasses Android’s internal resampling limitations, enabling true bit-perfect playback, even when streaming. You get absolute fidelity—no compromises.

Luxury Meets Technology – Inside and Out

• 6″ Full HD Display (2160×1080) – sharp, vibrant, and energy-efficient
• Any Layer HDI PCB – ultra-compact circuit design with minimal signal loss
• 99.9% Pure Copper Shielding – robust electromagnetic protection
• Perlinger Leather Case – crafted in Germany from shrunken calfskin, tanned and dyed for elegance and durability

The all-new 4.5 Generation User Interface brings your library to life with a vinyl-style album browser and the signature Crimson Theme. Designed around clarity, minimalism, and emotional engagement, it elevates not just how you hear your music, but how you connect with it.

Key Specs at a Glance

• Storage: 256GB internal + microSD up to 1.5TB
• Wi-Fi: Dual-band 2.4/5GHz
• Audio Support: PCM up to 32-bit/768kHz & native DSD512
• Bluetooth: LDAC, aptX™ Adaptive, BT Sink Mode
• USB DAC, DLNA, ReplayGain, Crossfeed, Wireless File Transfer
• Battery Life: Approx. 10 hours | Fast charging via QC 3.0
• Roon Ready (pending final certification)

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Conclusion: The SP4000 Isn’t Just a Player—It’s a Precision Instrument

The Astell&Kern A&ultima SP4000 is not merely a digital audio player. It’s a statement of intent—a masterfully crafted device that brings cutting-edge innovation and uncompromising sound quality into your pocket. Whether you’re streaming lossless, analyzing detail with reference headphones, or simply losing yourself in your favorite album, the SP4000 sets a new benchmark for what portable hi-fi can be.

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