The A&ultima SP4000 Review
Astell&Kern Unveils the A&ultima SP4000: A Flagship Built for the Future
Nearly three years after introducing the A&ultima SP3000, Astell&Kern has announced its successor — the A&ultima SP4000 — a flagship digital audio player engineered to deliver elevated performance and fidelity for discerning audiophiles.
At first glance, the SP4000 shares a familiar aesthetic with its predecessor: a robust 904L stainless steel chassis (the same material used in luxury watches) and a generous 6-inch touchscreen. However, beneath its refined exterior lies a comprehensive internal overhaul designed to push sonic performance to new heights.
A New Signal Architecture
The SP4000 debuts Octa audio circuit architecture, combining a single AK4191 digital processor with one AK4499EX analog DAC in a 1:1 configuration. Unlike the SP3000, which utilized dual DACs, this updated design aims to eliminate unwanted signal interference, enabling more precise signal transmission and greater separation — translating into cleaner, more accurate audio reproduction.
High Driving Mode & Advanced DAR
For those who demand power and finesse, the SP4000 introduces a new High Driving Mode, engineered to offer stable output across demanding headphones while preserving the subtlest sonic nuances. According to Astell&Kern, this mode delivers deeper immersion, clarity, and emotional resonance — particularly in dynamic or layered recordings.
In addition, the SP4000 features Advanced DAR (Digital Audio Remaster) technology — the second generation of A&K’s proprietary remastering engine. It intelligently upscales digital music files to more closely resemble the original studio recording, enhancing texture and harmonic detail for a richer listening experience.
Full Android Integration & ADP Playback
For the first time in an A&ultima player, the SP4000 runs a fully integrated Android OS with native access to the Google Play Store — removing the need for sideloading and streamlining app installation.
To maintain audio integrity within the Android ecosystem (notorious for its SRC limitations), Astell&Kern developed ADP (Astell&Kern Direct Path). This proprietary system ensures bit-perfect, lossless playback even when streaming — a notable advancement for audiophiles who rely on cloud-based platforms.
Connectivity and Audio Support
The SP4000 supports native playback of PCM files up to 32-bit/768kHz and DSD512, while offering wireless streaming via Bluetooth with aptX Adaptive and LDAC. Whether used with high-end IEMs or studio monitors, the SP4000 promises top-tier sonic accuracy and flexibility across wired and wireless setups.
Availability and Expected Pricing
While official pricing and release details remain unconfirmed, expectations are high. Given the SP3000 launched at $3,699, the SP4000 is anticipated to carry a premium price point. It will be available in two finishes: Black and Silver.
TACTIC FLEX Outlook
Pros
- Refined circuit design with true 1:1 signal path
- High Driving Mode for demanding headphones
- Advanced DAR and full Android OS with Play Store access
- Bit-perfect streaming via proprietary ADP tech
Cons
- Expected to command a higher price than its predecessor
- Stainless steel build adds weight and bulk
- Still aimed at a niche, high-end market
Final Word
With the A&ultima SP4000, Astell&Kern isn’t just refreshing its flagship — it’s redefining the standard for what a portable high-fidelity player can be. From architectural changes to forward-looking software integration, the SP4000 stands as a statement piece for audiophiles who refuse to compromise.