Astell & Kern A&ultima SP1000 review

Astell & Kern’s hulkish new SP1000 music player is like VR for your ears

As makers of some of the most acclaimed portable high-resolution audio gear this side of the galaxy, Astell & Kern craft meticulously designed, feature-packed, and some might say gratuitous ways for audiophiles to satiate their obsession on the go. The latest example is the A&ultima SP1000, a $3,500 brick of steel and glass that takes over for AK’s previous flagship, the AK380, on a fanatical quest for pure sonic perfection. And while it’s no easy task toting it around, or even saying the name, as our Astell & Kern A&ultima SP1000 review reveals, the SP1000 gets closer to the brand’s unachievable end game than ever.

A regal entrance

Astell & Kern was not messing around when packaging the SP1000, which arrives in a custom-made wooden box, carefully encased within a cardboard shell. We honestly couldn’t figure out what this little lump of lead was when we first got the box — at 13.64 ounces, it feels weighty enough to anchor a catamaran. Inside the box, the blocky device sits sunken in hard foam with a protective sticker guarding its long, bezel-less display.

It feels weighty enough to anchor a catamaran.

Sharp stainless-steel bezels have become an A&K staple, and the angular A&ultima doesn’t buck that trend, but the ‘80s Lamborghini vibe of the AK240 has been curtailed. At the back, a translucent plate covers AK’s familiar carbon threading. Welcome accessories include a crushed-brown leather case, a long USB-C to USB cable, and even a few screen protectors.

The goods

Like its flagship predecessor, the A&ultima boasts top-level high-resolution audio support, offering support for virtually any audio file in your collection (WAV, FLAC, WMA, ALAC, APE, AAC, DSF, etc.) with a max resolution of 32bit/384kHz for PCM files and native playback of DSD files at up to 11.2MHz. A&K claims it’s capable of “Mastering Quality Sound,” and that isn’t hype: You’ll be hard pressed to find a file at the resolution supported here outside a professional mastering or recording studio.

As the new “A&ultima” series moniker implies (which we’re not really wild about) the SP1000 is the first in Astell & Kern’s entirely new line of portable players, and as such, it’s loaded with shiny new hardware. That includes a new octa-core CPU for faster response and performance, an ultra-wide HD5 LCD display, and a new power and volume control wheel for more intuitive operation, with volume control at an impressively granular 150 increment levels. Powering the ship are dual AK4497EQ DAC (Digital-to Analog Converter) chips from Asahi Kasei Microdevices AKM — each dedicated to a single stereo channel — replacing the AK380’s AK4490 chips.

Connection options include an unbalanced headphone output with 2 ohms impedance and a balanced line-out (both of which offer signal to noise ratios and distortion rates that best the AK380), a USB-C port for fast charging, a DAC connection to your computer, and an SD slot for additional storage to go along with 256GB of internal storage. The headphone output also doubles as a digital optical output. Battery life is rated around 12 hours per charge at 50 percent volume.

The player runs on AK’s latest Android-based operating system, which means Mac users will need to download an Android file-transfer app before loading. AK’s OS has come a long way since the original AK100, as you might imagine, and basic navigation is faster and more intuitive than the AK240 we reviewed a couple years back, as well. We especially like the swipe-down control panel, which allows easy access to options like Wi-Fi, Bluetooth (yes, it has Bluetooth for some reason), external storage drives, EQ, Line Out selection, and even a quick key to switch operation from regular mode to DAC mode for your Mac or PC. Like other AK devices, three playback control keys rest on the left side, but between the intuitive touch screen and the volume knob, we barely used them.

The SP1000 comes with streaming apps Tidal and Groovers+, but seeing that the device is tied to Wi-Fi anyway, it’s often just as easy to connect to your preferred PC and access anything and everything online from there.

While we have no doubt you’ll want to take the SP1000 on the road, it’s not exactly the most travel-friendly device. It’s big, bulky, and the sharp corners threaten to stab through pockets. The leather case softens things up a bit, but the SP1000 is more briefcase beast than pocket player.

The sound

When you get to this level of quality, it can be difficult for even the most persnickety audiophile to note minor differences between the latest flagship device and previous models. That said, the SP1000 is easily one of the most subtly perfect ways to listen to audio we’ve experienced, besting even the AK240. Not a note, not a keystroke, not even a single press of a piano pedal is overlooked by this dynamic, immaculately detailed audio device, and words like sibilance or distortion can be left at home.

After spending a week with the SP1000, the best way we can describe it is as a sort of VR device for your ears. The sound seems to open before you, teleporting you from your desk or train seat deep into another aural realm entirely. We primarily experienced this journey via our two favorite pairs of reference headphones: Audeze’s open-back EL-8, and Ultimate Ears’ Reference Monitor in-ears, each offering equally engaging, but notably different sonic experiences.

Astell & Kern A&ultima SP1000 review
Bill Roberson/Digital Trends

With the EL-8, soundscapes unfold as though you’re flying hundreds of feet above the ground. Each instrumental expression seems to appear before you like a point on some grand horizon, then sweep closer until its full force is blazing before you. Listening to our 24bit/96kHz version of Muse’s Black Holes and Revelations (frankly, not even one of our top-level hi-res recordings) gave us chills even while focused on other tasks. Details are nearly perfectly exposed, but even more striking is the dynamic expression, which allowed us, once again, to chase that audiophile dragon and experience the well-worn Muse album as a freshly minted sonic experience.

The struggles of instrumental masking become a thing of the past with the SP1000, as each instrument that enters seems to find a new space in the stereo landscape to inhabit. In this case, it allowed us to hear deeper exposures of buzzy sawtooth waves and synths, and fully uncover vocal lines — like the underriding “de-de-de-de-de-de-de-de” part in the later chorus of Supermassive Black Holes — for the very first time. This is truly a mastering-quality experience if we’ve had one, and being from the studio world, this author has.

The SP1000’s bulky size and weight make it more briefcase beast than pocket player.

Even Spotify streams from your computer are given the royal treatment with the SP1000, as near-perfect recordings like Radiohead’s A Moon Shaped Pool open up brilliantly, even in their compressed form. Somehow the near-perfect silence allowed by the device unleashes more space, and therefore deeper renderings of each instrument, layered in a rich gloss, while remaining snappy at the attack of notes. We even gained a new respect for one song, Decks Dark — new instruments arise like so many checkered plots of land below, while the creamy piano in the left side constantly oozes into the center channel in haunting reflection.

It should be mentioned that, while EQ is at your discretion, we were also really impressed with the treatment of bass across our entire catalog; it’s full, it’s warm, and it supports the upper register the way steel and concrete support a skyscraper. The SP1000 is not kind to poorly produced indie tracks, however, and distortion on songs like Father John Misty’s Real Love is ramped up to near uncomfortable levels.

Switching from the EL-8 to our Ultimate Ears RM tightened the sonic picture significantly, transporting us from our high-flying perch to more of a POV-style studio experience. Calling up the CD-resolution version of some of our favorite jazz tracks we were suddenly seated at the drum kit in-studio, “watching” the ride cymbal buzz as the lightning quick drum taps of Ahmad Jamal’s Silver encircled us in a veritable whirlpool of percussion.

Some tracks, such as Akron/Family’s River sounded like an entirely new mix when played back through the SP1000. The shakers at the song’s intro take so long to grow to full volume, it’s as if you’re watching them approach from afar through a telescope. The utter lack of any harmonic distortion lets the volume keep creeping until suddenly you realize you’re blasting the tune, even at dozens of clicks below max volume.


While certainly not for those with light pockets — or small ones — Astell & Kern’s latest flagship audio player once again raises the bar for the brand as the high-res portable player to beat. Those looking for a transformative portable playback device need look no further than the A&ultima SP1000. Now, if you’ll excuse us, we’ve got to get back to flying the friendly SP1000 skies. We hope to see you up there.