Astell&Kern A&Ultima SP4000T Digital Audio Player

Reimagine Analogue Sound, with the A&ultima SP4000T by Astell&Kern.

A&ultima SP4000T is the culmination of nearly two years of dedication and exploration, beginning from the planning and development stages of SP3000T.

DAC, Tube, and AMP — the essential elements of high-end audio — may be accessible to anyone. Yet even with the same elements, what is ultimately created from them is an entirely different matter. Using the canvas of SP4000, the essence of digital sound, Astell&Kern held onto one defining question over the past two years: "How can we bring deeper emotion through analog sound?"

The answer was drawn with sincerity and endless passion, stroke by stroke. Every trace of that journey is distilled into SP4000T. Astell&Kern’s own analog sound — comfortable to listen to, yet revealing new depth and character the longer you experience it.

Discover it for yourself with A&ultima SP4000T.

Silver version available now. SP4000T Copper Edition due later in 2026.

Features

• Next-Gen Quad-Tube Architecture - Features four genuine vacuum tubes inside a portable chassis, providing an deeply immersive, rich, and musical analogue sound signature that standard solid-state players cannot replicate.
• The Revolutionary Triple Amp System - Gives you total sonic flexibility by letting you choose between surgical OP-AMP precision, warm Tube AMP flavour, or a Hybrid Mode that dynamically blends the best of both worlds.
• Advanced Triode & Pentode Switching - Allows you to fine-tune your analog experience on the fly, offering Triode mode for smooth, organic acoustic textures or Pentode mode for a punchier, high-energy modern sound.
• Flagship AKM HEXA-DAC Architecture - Utilizes separate dual AK4191EQ digital processors and dual AK4499EX DAC chips, isolating the digital and analog signal paths to achieve an ultra-low noise floor and breathtaking resolution.
• 2nd-Gen Anti-Microphonic Isolation - Incorporates a custom 5-stage mechanical shock absorption system and a 99.9% pure copper shield can that floats the vacuum tubes, completely eliminating internal vibration noise and microphonic ring.
• High Driving Mode for Demanding Headphones - Engineered with a robust, parallel operational-amplifier design that effortlessly drives power-hungry, high-impedance headphones without requiring an external desktop amplifier.
• Snappy Performance & Massive Display - Powered by a Snapdragon octa-core processor and 8GB of DDR4 RAM for lightning-fast library indexing, paired with a gorgeous, sprawling 6-inch Full HD screen for premium visual navigation.

Specifications

• Model: SP4000T (PPF52)
• Body Color: Silver, Copper
• Body Material: Stainless Steel, Copper
• Display: 6-inch 2K (2160 × 1080) touch screen
• Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF
• Sample Rate: PCM 8kHz–768kHz (8/16/24/32 bits per sample); DSD Native: DSD64 (1-bit, 2.8MHz), DSD128 (1-bit, 5.6MHz), DSD256 (1-bit, 11.2MHz), DSD512 (1-bit, 22.4MHz), Stereo
• Output Level: Unbalanced 4.2Vrms; Balanced 8Vrms (No Load)
• CPU: Octa-Core
• DAC: AKM4191EQ ×2 + AKM4499EX ×2
• Vacuum Tube: RAYTHEON JAN6418 ×4 (Quad Tube)
• Decoding: Supports up to 32-bit / 768kHz bit-to-bit playback
• Input: USB Type-C (charging, PC and Mac connectivity)
• Outputs: 3.5mm Unbalanced / Optical; 4.4mm Balanced (5-pole only)
• Wi-Fi: 802.11 a/b/g/n/ac/ax (2.4GHz / 5GHz)
• Bluetooth: Version 5.2 with A2DP, AVRCP, Qualcomm aptX HD, LDAC, LHDC, SBC and AAC
• Dimensions: 85.7 × 150 × 19.5mm (3.37 × 5.9 × 0.76 inches)
• Weight: Approximately 565g (19.93oz)
• Feature Enhancements: OTA firmware updates supported
• Operating Temperature: 0°C to +40°C (32°F to 104°F)
• Frequency Response: ±0.006dB (20Hz–20kHz) Unbalanced/Balanced; ±0.06dB (20Hz–70kHz) Unbalanced/Balanced
• Signal-to-Noise Ratio: 124dB @ 1kHz (Unbalanced); 125dB @ 1kHz (Balanced)
• Crosstalk: -136dB @ 1kHz (Unbalanced); -145dB @ 1kHz (Balanced)
• Total Harmonic Distortion + Noise (THD+N): 0.0006% @ 1kHz (Unbalanced); 0.0004% @ 1kHz (Balanced)
• IMD SMPTE: 0.0004% (800Hz / 10kHz, 4:1), Unbalanced and Balanced
• Output Impedance: 0.7Ω (3.5mm Unbalanced); 1.7Ω (4.4mm Balanced)
• Clock Jitter: 25pS (Typical)
• Reference Clock Jitter: 200 femtoseconds
• Battery Capacity: 7,450mAh, 3.8V Li-Polymer
• Continuous Playback: Up to 10 hours (FLAC 16-bit/44.1kHz, Volume 80, LCD Off, Low Gain)
• Charging Time: Approximately 5 hours (PD 3.0 charging)
• Built-in Storage: 256GB NAND
• Expandable Storage: microSD card slot (up to 1.5TB)
• Supported Operating Systems: Windows 10 (32/64-bit), Windows 11 (32/64-bit), macOS X 10.7 or later

Included

• 1 x Astell&Kern A&ultima SP4000T player
• 1 x Premium Badalassi Carlo Minerva Case
• 1 x USB-C to USB-C cable (1.00 metre)
• 3 x screen protectors
• 1 x Quick start guide

More Information

• A&Ultima SP4000T Digital Audio Player. by Astell&Kern