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  • Astell&Kern A&ultima SP4000T

Astell&Kern A&ultima SP4000T

Industry-First Digital Audio Player with MIL-Spec Vintage Vacuum Tube

  • Industry-first DAP with MIL-Spec Vintage Vacuum Tube Raytheon JAN6418 in Quad Configuration
  • Industry-first DAP with Triple Tube Mode (Triode, Ultra Linear, Pentode)
  • T Series Signature feature: Triple AMP System
  • Adjustable Tube Current with Three Levels
  • High Driving Mode, ESA, and Advanced DAR for superior sound quality
  • Full Open Android with Enhanced Octa-Core CPU
Regular price $5,172.00
Sale price $5,172.00 Regular price
Unit price

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Astell&Kern A&ultima SP4000T

Astell&Kern A&ultima SP4000T

Regular price $5,172.00
Sale price $5,172.00 Regular price
Unit price

Reimagine Analog Sound, A&ultima SP4000T

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

Supports High Driving Mode for RAYTHEON JAN6418 in a Quad configuration.

The SP4000T is the industry's first DAP to feature the MIL-Spec vintage vacuum tube RAYTHEON JAN6418 in a Quad configuration.

With independent dual-tube structures dedicated to the left and right channels respectively, the channel-separated design — once exclusive to home audio high-end tube amplifiers — has finally been brought to the world of DAPs.

But the essence is not the number of tubes. Managing multiple highly sensitive vacuum tubes is far more than a simple matter of addition. It demands answers to countless questions: How do you pair tubes with subtly different noise characteristics and gain rates? How do you overcome microphonic noise? How do you minimize output variation between left and right channels?

The SP4000T is the industry's first DAP to feature Triple Tube Mode.

  • Triode Mode — The Purest Voice of the Tube
  • Ultra Linear Mode — The Aesthetics of Balance
  • Pentode Mode — The Most Powerful Voice of the Tube

With independent dual-tube structures dedicated to the left and right channels respectively, the channel-separated design — once exclusive to home audio high-end tube amplifiers — has finally been brought to the world of DAPs.

But the essence is not the number of tubes. Managing multiple highly sensitive vacuum tubes is far more than a simple matter of addition. It demands answers to countless questions: How do you pair tubes with subtly different noise characteristics and gain rates? How do you overcome microphonic noise? How do you minimize output variation between left and right channels?

The four tubes in the SP4000T do not operate independently — they work in a differential configuration, with each pair facing the other in mirror symmetry. In this precise balance, music signals are amplified with twice the clarity, while common-mode noise is mutually cancelled and eliminated.

Each of the four tubes is precisely measured for its noise and gain characteristics before being paired, then fully isolated from noise through independent modular flexible PCBs and a multi-layered architecture — a design that only Astell&Kern, with its long experience in analog circuits and vacuum tubes, could bring to life.

Sound Design With DAC Filters

Design your own sound style with 7 DAC filters.

Sound Type
 
Impulse Response
 
Filter name
 
Remarks
 
Edge
  • Natural TonewaveSuper Slow Roll-offNo echo reproduces
    natural sound    Ultra-Sharp
  • Acoustic TonewaveShort Delay Slow Roll-offMinimal echo reproduces
    original sound    Sharp
  • Traditional TonewaveSlow Roll-offMinimal echo reproduces
    original sound    Middle
  • Harmonic SoundwaveLow dispersionShort echo reproduces
    original sound    Middle
  • Acoustic SoundwaveShort Delay Sharp Roll-offPost echo enhances
    bass sound    Sharp
  • Traditional SoundwaveSharp Roll-offPre and post echoes make
    powerful sound    Slow

The Premium Leather Case

The bundled leather case for the SP4000T was crafted using 'MINERVA' leather from 'BADALASSI CARLO', a renowned leather workshop located in the San Miniato district of Florence, Italy.

Badalassi Carlo is a tannery that has been producing leather for over 40 years, combining the traditional Tuscan vegetable tanning methods with the theories and techniques of CARLO BADALASSI, a former leather-school professor from the Santa Croce region.

Android 15

Keeping pace with the shift toward streaming-centric listening, the SP4000T runs the latest Android 15 — delivering top-tier analog sound quality alongside exceptional convenience.

Specifications

General Information

  • SP4000T (PPF52)

  • Silver, Copper

  • Stainless Steel, Copper

  • 6inch 2K (2160 x 1080) touch screen

  • OCTA-Core

  • AKM4191EQ x2 + AKM4499EX x2

  • RAYTHEON JAN6418 x4 (Quad Tube)

  • Support up to 32bit / 768kHz Bit to Bit playback

  • 85.7mm × 150mm × 19.5mm (3.37" × 5.9" × 0.76")

  • About 565g (19.9oz)

  • 0℃ ~ + 40℃ (32℉~ 104℉)

Audio Formats & Sample Rates

  • WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF

  • 8kHz ~ 768kHz (8/16/24/32bits per Sample)

  • DSD64 (2.8MHz), DSD128 (5.6MHz), DSD256 (11.2MHz), DSD512 (22.4MHz)

Inputs & Outputs

  • USB Type-C (Charging & PC & MAC)

  • 3.5mm, Optical Out (3.5mm)

  • 4.4mm (5-pole only supported)

  • Unbalanced 4.2Vrms │ Balanced 8Vrms

Wireless Connectivity

  • 802.11 a/b/g/n/ac/ax (2.4/5GHz)

  • V5.2, aptX HD, LDAC, LHDC, SBC, AAC

Audio Performance

  • Unbalanced: ±0.006dB │ Balanced: ±0.006dB

  • Unbalanced: ±0.06dB │ Balanced: ±0.06dB

  • 124dB @ 1kHz (Unbalanced) │ 125dB @ 1kHz (Balanced)

  • -136dB @ 1kHz (Unbalanced) │ -145dB @ 1kHz (Balanced)

  • 0.0006% @ 1kHz (Unbalanced) │ 0.0004% @ 1kHz (Balanced)

  • 0.0004% 800Hz 10kHz (4:1) Unbalanced/Balanced

  • Unbalanced 3.5mm (0.7Ω) │ Balanced 4.4mm (1.7Ω)

Clock & Timing

  • 25pS (Typ.)

  • 200 Femto Seconds

Storage

  • 256GB NAND

  • microSD x1 (Max. 1.5TB)

Battery

  • 7,450mAh 3.8V Li-Polymer

  • about 5 hours (PD3.0 Charging)

Additional Features

  • Supported

  • Supported (OTA)

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