Astell & Kern A&ultima SP4000T Quad-Tube DAP Debuts at High End Show Vienna 2026

Astell & Kern has unveiled the A&ultima SP4000T, a flagship digital audio player that combines vacuum tube warmth with modern solid-state precision. The device targets audiophiles who demand the highest fidelity from portable sources.

Quad-tube analog stage and dual DACs

The SP4000T is the latest addition to the A&ultima series, a line known for premium build and advanced audio circuitry. It runs Android 15 on an octa-core processor, with 256GB of internal storage expandable to 1.5TB via microSD. The 6-inch Full HD touchscreen provides intuitive control over music libraries and streaming apps.

Specifications

• Processor: Octa-core CPU
• Operating System: Android 15
• Storage: 256 GB internal, expandable up to 1.5 TB via microSD
• Display: 6-inch Full HD touchscreen
• Wi-Fi: Dual-band 802.11ax

At the heart of the SP4000T are dual AKM4191EQ digital signal processors feeding dual AKM4499EX DACs. The analog stage employs four Raytheon JAN6418 vacuum tubes, a design that introduces subtle harmonic distortion prized by tube enthusiasts. The player supports DSD512 and PCM 768kHz lossless audio, with wireless codecs including aptX HD, LDAC, and LHDC.

Frequency response measures ±0.006dB from 20Hz to 20kHz and ±0.06dB from 20Hz to 70kHz, with total harmonic distortion below 0.0006% and signal-to-noise ratio exceeding 124dB. Wired connectivity includes a 3.5mm unbalanced and a 4.4mm balanced output. The player also functions as a USB DAC for computers.

The SP4000T packs a 7450 mAh battery rated for up to 10 hours of playback, with a full charge taking five hours. Pricing is expected above $3,900 USD, based on the previous SP4000 model's entry-level price. The global debut occurs at the High End Show Vienna 2026 on June 4, 2026.

Astell & Kern positions the SP4000T as a successor to the SP4000, retaining the dual-DAC architecture while adding the quad-tube output stage. The company has not disclosed performance benchmarks or direct comparisons to prior models. The device is confirmed as a production unit, not a prototype.

The A&ultima SP4000T delivers a confirmed combination of vacuum tube circuitry, high-resolution DACs, and expandable storage in a portable form factor. Audiophiles can expect availability starting June 4, with pricing above $3,900.