Astell&Kern A&ultima SP4000T | Vacuum Tube Digital Audio Player

Discover the Astell&Kern SP4000T, the Ultimate DAP, Where Analog Warmth and Digital Precision Collide

• 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

A New Standard in Tube 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.

The four tubes in the SP4000T 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.

When four hearts beat as one in perfect balance, the tube's signature rich harmonics resonate with the deepest, most resonant sound ever heard in the SP4000T.

Triple Tube Mode

The SP4000T is the industry's first DAP to feature Triple Tube Mode. Combined with the T Series Signature Triple AMP Mode and the Tube Current level adjustment first found on the SP3000T, it offers up to 54 possible combinations tailored to any genre or preference, a true Analog Sound Palette.

Triode Mode: The Purest Voice of the Tube
This mode brings out the richest harmonic texture unique to vacuum tubes, letting the breath of a vocalist and the trembling of strings gently dissolve into a lush, lingering reverb.

Ultra Linear Mode: The Aesthetics of Balance
A design that blends the tonal color of Triode with the output of Pentode. The sound fades softly at its edges, yet carries a firm, solid core.

Pentode Mode: The Most Powerful Voice of the Tube
Maximizing tube amplifier output and dynamic range, this mode retains the tube's signature warmth while stripping away reverb — delivering a clean, powerful presence that speaks with directness and force.

The Perfect Harmony

A&ultima SP4000T, built on Astell&Kern's exclusive Teraton Alpha technology, achieves a perfect fusion of true analog sound from the Quad-configured Real Vacuum Tubes and the dynamic sound of the OPAMP.

SP4000T offers TUBE AMP mode for the authentic analog sound of a tube amplifier, OP AMP mode delivering Astell&Kern's signature clarity and expansive soundstage, and HYBRID AMP mode combining the best of both analog warmth and high-resolution output.

Anti-Microphonic Noise Architecture

The greatest technical challenge in applying vacuum tubes to a compact portable device is achieving low noise even at high resolution and high output. SP4000T introduces an upgraded 5-stage 2nd Generation Architecture (up from the previous 4-stage design) to suppress microphonic noise (noise generated in vacuum tubes from even minor external vibrations). 

HEXA Audio Circuit Structure

The SP4000T integrates dual AK4499EX DACs, AKM’s latest flagship, paired with dedicated AK4191EQ processors for each left and right channel, forming a fully discrete audio circuit architecture.

Unlike conventional DAPs that handle both digital and analog signals inside the DAC, the SP4000T's audio circuit uses a dedicated digital delta-sigma modulator (AK4191EQ) to reduce noise in the digital signal before passing it to a completely isolated Analog DAC (AK4499EX) for independent analog signal processing.

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.

Vegetable tanning is an eco-friendly leather-making process, slow and time-intensive, that tans hides using only plant-derived tannin extracts. Badalassi Carlo leathers employ the Tuscan vacchetta technique, after removing the hair from the hide, bovine bone powder-derived tallow is added during the vegetable oil tanning process.

Additional Features and Enhancements

• Astell&Kern's TERATON ALPHA
• Astell&Kern Direct Path Customization Technology
  
• 99.9% Pure Copper Shield Can
• Native DSD512, 32-bit/768kHz Support
• USB PD 3.0 Fast Charging
• Large 6" Full HD Display
• Enhanced Battery Protection Mode