Astell&Kern A&ultima SP4000 – Flagship Digital Audio Player

The Astell&Kern A&ultima SP4000 represents the pinnacle of portable high-resolution audio, designed for audiophiles seeking uncompromising sound quality. As the successor to the acclaimed SP3000, the SP4000 introduces a new Octa audio circuit architecture, delivering unmatched clarity, detail, and dynamics in a portable player. With its combination of advanced DAC technology, refined circuitry, and luxurious design, it sets a new benchmark in reference-grade digital audio players.

Key Features

• Octa Audio Circuit Architecture: Innovative design with eight DAC chips (AKM4191 x4 + AKM4499EX x4) for true Quad DAC performance
• Enhanced ESA Technology: Proprietary Enhanced Signal Alignment minimizes group delay and improves time-domain accuracy
• Powerful Output: High Driving Mode delivers 4.1 Vrms unbalanced and 8.2 Vrms balanced for demanding headphones
• Noise Suppression: Ultra Low Noise LDO Regulator and 99.9% pure copper shielding for pristine playback
• Full Android OS: First Astell&Kern flagship player with open Android system for broader app compatibility
• Premium Design: Stainless steel 904L chassis with a 6” 2K touch display and 4.5th gen UI
• Comprehensive Wireless Support: Dual-band Wi-Fi, Bluetooth 5.0 with LDAC, aptX HD, LHDC, AAC, and SBC
• Generous Storage: 256 GB internal memory plus microSD expansion up to 1.5 TB

Quick Specs

• DAC: 4x AKM4191 + 4x AKM4499EX (Quad DAC)
• CPU: Octa-core
• Display: 6" 2K (2160 × 1080) touchscreen
• Output Level: 4.1 Vrms unbalanced, 8.2 Vrms balanced
• Frequency Support: PCM up to 32-bit/768 kHz, DSD512 native
• Outputs: 3.5 mm unbalanced/optical, 4.4 mm balanced
• Wireless: Wi-Fi 802.11 a/b/g/n/ac (2.4/5 GHz), Bluetooth 5.0
• Internal Memory: 256 GB NAND
• Expandable Memory: microSD (up to 1.5 TB)
• Battery: 8,000 mAh lithium-ion
• Dimensions: 85 × 149.8 × 19.5 mm
• Weight: approx. 615 g

What’s in the Box

• Astell&Kern A&ultima SP4000
• Protective film
• microSD card slot cover
• USB Type-C cable
• Quick Start Guide & Warranty Card

Use Cases / Ideal For

The SP4000 is ideal for audiophiles, recording professionals, and discerning listeners who demand studio-grade playback on the go. Perfect for high-resolution streaming, reference listening with flagship IEMs and headphones, and use as a high-quality DAC in desktop setups.

Pros & Cons

✅ Pros:

• Class-leading Octa audio circuit for unmatched sound quality
• Quad DAC implementation with ultra-low noise design
• Premium stainless steel build with 6” 2K display
• Full Android OS for app flexibility
• Expandable storage up to 1.5 TB

⚠️ Cons:

• Large and heavy compared to entry-level DAPs
• Flagship performance comes at a premium price

The Astell&Kern A&ultima SP4000 is more than a music player—it is a flagship reference instrument for those who want nothing less than the very best portable audio experience.