Astell & Kern is bringing vacuum-tube warmth to portable audio with the new A&ultima SP4000T. The flagship digital audio player packs four Raytheon JAN6418 tubes into a handheld chassis. It makes its global debut at the High End Show Vienna 2026 on June 4.
Quad-tube design with dual DACs
The SP4000T runs Android 15 on an octa-core processor. It has 256 GB of internal storage, expandable to 1.5 TB via microSD. A 6-inch Full HD touchscreen handles navigation. Connectivity includes dual-band 802.11ax Wi-Fi and Bluetooth 5.2.
Specifications
- CPU: octa-core
- OS: Android 15
- Internal Storage: 256 GB
- Expandable Storage: up to 1.5 TB via microSD
- Display: 6-inch Full HD touchscreen
Audio processing relies on dual AKM4191EQ digital signal processors and dual AKM4499EX DACs. The four Raytheon JAN6418 vacuum tubes can operate in Triode, Pentode, or Ultra Linear modes. Users can fine-tune settings to shape the sound to their preference.
The player supports DSD512 and PCM 768kHz lossless streams. Wireless codecs include aptX HD, LDAC, LHDC, SBC, and AAC. Wired output is via 3.5mm unbalanced or 4.4mm balanced jacks. The device also works as a USB DAC with a computer.
Frequency response measures ±0.006dB from 20Hz to 20kHz and ±0.06dB from 20Hz to 70kHz. Total harmonic distortion is below 0.0006%, and signal-to-noise ratio exceeds 124dB. Battery life reaches 10 hours on the 7,450 mAh cell, with a five-hour recharge time.
Pricing is expected above $3,900 USD, according to the source. The SP4000T will be available in copper or stainless steel. It comes with a Badalassi Carlo leather case made from Minerva leather.
The A&ultima SP4000T combines tube amplification with modern digital audio. It targets audiophiles seeking high-resolution portable playback. Confirmed specs include the quad-tube design, dual DACs, and extensive codec support.
Source: NotebookCheck
