High End Vienna 2026 is the chosen venue for the official launch of the Astell&Kern SP4000T digital audio player, the latest to join the flagship A&ultima line, and the Clarus in-ear monitors.
Astell&Kern A&ultima SP4000T Quad Valve Player
The A&ultima SP4000T, which will be available in Stainless Steel and Copper versions, sports a fully discrete circuit architecture that separates digital and analogue signal processing, with dual AK4499EX DACs and dedicated AK4191EQ processors per channel. The company promises this reduces noise and heightens clarity, depth, and purity across the entire signal path while supporting native playback up to 32-bit/768kHz PCM and DSD512.
However, Astell&Kern's new SP4000T DAP also has bragging rights to being the industry's first DAP to feature matched Raytheon JAN6418 MIL-Spec vintage vacuum tubes in a quad configuration, resulting in dual-tube structures dedicated to each channel. Additionally, the SP4000T benefits from an upgraded 5-stage, second-generation anti-microphonic architecture that suppresses microphonic noise.
Triple Tube Mode in the SP4000T is apparently another DAP first, and when combined with the T Series Signature Triple Amp Mode and the Tube Current level adjustment, the company states you have up to 54 possible combinations, offering quite a diverse “analogue sound palette.”
There are also three tube sound modes available: Triode Mode is said to emphasise rich harmonics and “lush, lingering warmth” ideal for vocals and acoustic instruments. Alternatively, Ultra Linear Mode balances the tonal richness of Triode with the power and control of Pentode, producing a “refined yet authoritative” sound suited to a wide range of music genres. Finally, Pentode Mode, which A&K says focuses on maximum output and dynamic impact, “preserving tube warmth whilst delivering a cleaner, more direct, and energetic presentation.”
The SP4000T incorporates High Driving Mode with a parallel op-amp configuration for greater dynamic range, while ESA (Enhanced Signal Alignment) technology minimises group delay and frequency distortion, and Advanced DAR technology restores lost harmonics before upsampling for more natural, lifelike playback.
Astell&Kern’s Teraton Alpha tech is on board for effective noise removal from audio power sources, distortion-free amplification, and noise prevention from the audio interface.
This leaves the quad-configured tubes and advanced op-amp design to deliver both authentic analogue warmth and ultra-high-resolution clarity.
Moreover, you can choose between dedicated Op Amp Mode for powerful dynamics, expansive detail, and low-noise precision, or Tube Amp Mode for the rich, emotional character and natural soundstage of valves. Thanks to the five-stage Hybrid Amp Mode, you can blend the strengths of both amps and fine-tune the balance between them to your own taste.
In The Digital Domain
The Astell&Kern SP4000T runs Android 15 with full Google Play support; however, ADP (Astell&Kern Direct Path) tech bypasses Android’s standard sample-rate conversion limitations to enable true lossless, bit-perfect playback from streaming services.
The new DAP also sports Astell&Kern’s first dual Wi-Fi antenna design, with internal testing showing up to twice the 5GHz download speed of previous models.
It also offers 256GB of internal storage with microSD expansion up to 1.5TB, and features a 6-inch Full HD touchscreen, dual-band Wi-Fi, DLNA networking, USB audio output, and USB DAC functionality for Mac and Windows PCs.
There is also support for aptX Adaptive and LDAC codecs, whilst BT Sink mode allows the SP4000T to function as a high-quality Bluetooth DAC for external devices such as smartphones. Features like ReplayGain, AK File Drop wireless transfers, USB PD 3.0 fast charging, and customisable battery protection further improve everyday usability.
Tanned Hides
The SP4000T is packaged in a premium Cognac-coloured leather case from Badalassi Carlo.
Two additional premium leather cases will also be available: a black case made from cowhide by Gruppo Mastrotto, and an olive-coloured case of vegetable-tanned leather by Badalassi Carlo.
Astell&Kern Clarus: Nine Dedicated Drivers
Clarus is the fourth model in Astell&Kern's IEM series, and features a 6061-T6 aluminium construction. However, the real headline is that Clarus is designed around a nine-driver tribrid architecture.
We’re informed that this approach enables each driver to perform at its best within its dedicated range.
The result is that a dynamic driver delivers the natural weight and depth of the low frequencies, a precisely arranged array of Balanced Armature (BA) drivers reproduces the detail and resolution of the mids and highs, and the latest MEMS drivers render upper frequencies with “exceptional precision.”
Clarus and SP4000T can be found at the Astell&Kern booth HX4, M04 during High End Vienna 2026.
Pricing, availability and further details will be confirmed in due course.
For more information visit Astell&Kern
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Posted in: Headphones
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