Description
Astell&Kern SP4000T
The Astell&Kern SP4000T is a range-topping audiophile player from Astell&Kern, offering high-end luxury and stunning performance, Astell&Kern has set the standard for perfect sound using the latest innovative technology with the A&ultima series.
RAYTHEON JAN6418 Quad – A New Standard in Tube Configuration
The SP4000T is the industry’s first DAP to feature MIL-Spec RAYTHEON JAN6418 vacuum tubes in a Quad configuration. Using a precision-matched, mirror-symmetry dual-tube design for left and right channels, it delivers exceptional clarity while cancelling noise and distortion. Each tube is individually measured and isolated within a multi-layer architecture, resulting in a perfectly balanced system that produces rich harmonics and deeply refined analogue sound.
Design
The Astell&Kern SP4000T is a flagship DAP focused on pure analogue sound, featuring the industry’s first Quad real vacuum tube configuration for a deeply immersive listening experience. As the successor to the SP4000, its “Burst” design concept expresses concentrated energy radiating from the centre, with a sculpted form anchored by the signature Volume Wheel, reflecting both Astell&Kern’s heritage and the richness of analogue sound.
Features Astell&Kern SP4000T:
- 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.
Architecture
The most challenging aspect of applying vacuum tubes to portable devices is maintaining low noise levels even at high resolutions and high outputs.
Equipped with four vacuum tubes—twice as many as its predecessor—the SP4000T features a 5-stage, 2nd-generation architecture that has evolved one step further from the previous 4 stages to suppress microphonic vibrations, which can generate noise from even minor external shocks. This represents the optimal combination found through Astell&Kern’s unique know-how and years of iterative design and verification.
1. Flexible PCB Independent Modularity — Designed to be completely separated from the Main PCB
2. Silicone Bottom Cushion — Primary shock absorption for the vacuum tubes
3. Custom-Made Silicone Tube — Mitigation of shocks entering through the leads
4. Silicone Damper Design — Suspends the vacuum tubes to completely isolate them from external vibrations
5. Copper Shield Can — Covers the entire vacuum tube to maximize suppression of even minute noise
Premium Leather Case
The standard leather case of the SP4000T utilizes MINERVA leather from the Badalassi Carlo tannery in San Miniato, Florence, Italy.
Badalassi Carlo is a tannery that has been operated for over 40 years by Carlo Badalassi, a former professor at the Santa Croce Leather School, who has perfected traditional Tuscan vegetable leather processing methods. With a philosophy of avoiding mass production and pursuing high quality in small quantities, it is a workshop preferred by renowned manufacturers who prioritise leather quality above all else.
MINERVA leather is produced using a vegetable tanning method that utilises only tannins extracted from plants. It achieves a deep texture and natural lustre by applying the traditional Tuscan Vacchetta technique, which involves processing the leather with bovine horn oil.
The case is available in Cognac colour and features a full-cover design that envelops the entire product, ensuring a perfect fit. Another unique detail of this case is the pattern on the back, which is shaped to allow the vacuum tube LED to shine through softly.
GENERAL SPECIFICATIONS
Model: SP4000T (PPF52)
Body Colour: Silver
Body Material: Stainless Steel
Display: 6-inch 2K (2160 x 1080) touch screen
Dimensions: 3.37″ W x 5.9″ H x 0.76″ D (85.7mm W x 150mm H x 19.5mm D)
Weight: About 19.9 oz (565g)
Input: USB Type-C input (for charging & PC & MAC)
Outputs: Unbalanced Out (3.5mm), Optical Out (3.5mm), Balanced Out (4.4mm, only 5-pole supported)
Wi-Fi: 802.11 a/b/g/n/ac/ax (2.4/5GHz)
Bluetooth: V5.2 (A2DP, AVRCP, Qualcomm aptX HD, LDAC, LHDC, SBC, AAC)
Feature Enhancements: Firmware upgrade supported (OTA)
Operating Temperature: 0℃ ~ + 40℃ (32℉~ 104℉)
Built-in Memory: 256GB [NAND]
External Memory: microSD x1 (Max 1.5TB)
Battery Capacity: 7,450mAh 3.8V Li-Polymer
Charge Time: About 5 hours (PD3.0 charging)
Playback Time: About 10 hours (Standard: FLAC, 16bit, 44.1kHz, Vol.80, LCD Off, Low Gain)
Supported OS: Windows 10, 11 (32/64bit) MAC OS X 10.7
CLOCK SOURCE
Clock Jitter: 25pS (Typ)
Reference Clock Jitter: 200 Femto Seconds
AUDIO SPECIFICATIONS
Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF
Sample Rate:
PCM : 8kHz ~ 768kHz (8/16/24/32bits per Sample)
DSD Native: DSD64(1bit 2.8MHz), Stereo / DSD128(1bit 5.6MHz), Stereo
DSD256(1bit 11.2MHz), Stereo / DSD512(1bit 22.4MHz), Stereo
Output Level: Unbalanced 4.2Vrms | Balanced 8Vrms (Condition No Load)
CPU: OCTA-Core
DAC: AKM4191EQ x2 + AKM4499EX x2
Vacuum Tube: RAYTHEON JAN6418 x4 (Quad Tube)
Decoding: Support up to 32bit / 768kHz Bit to Bit playack
Frequency Response:
±0.006dB (Condition : 20Hz~20kHz) Unbalanced │ ±0.006dB (Condition : 20Hz~20kHz) Balanced
±0.06dB (Condition : 20Hz~70kHz) Unbalanced │ ±0.06dB (Condition : 20Hz~70kHz) Balanced
S/N: 124dB at 1kHz, Unbalanced | 125dB at 1kHz, Balanced
Crosstalk: -136dB at 1kHz, Unbalanced | -145dB at 1kHz, Balanced
THD+N: 0.0006% at 1kHz, Unbalanced | 0.0004% at 1kHz, Balanced
IMD SMPTE: 0.0004% 800Hz 10kHz (4:1) Unbalanced | Balanced
Output Impedance: Unbalanced Out 3.5mm (0.7 ohms) | Balanced Out 4.4mm (1.7 ohm)
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