Astell&Kern A&ultima SP4000 Drops at High End Munich 2025: Who Needs a Wardrobe When You Can Drop It All on a DAP?

Astell&Kern will be unveiling its latest flagship digital audio player, the A&ultima SP4000, at High End Munich 2025—and yes, it’s another beautifully overbuilt slab of audiophile obsession. Billed as the successor to the already overachieving SP3000, the SP4000 took three years of R&D and now rolls out with a refined Octa audio circuit architecture that promises even more sonic purity and power.

It’s the kind of device meant for people who scoff at the idea of using a phone for music playback—which, let’s be honest, still leaves iPhone users at the back of the pack when it comes to serious audio.

Sure, the DAP market isn’t booming, especially with smartphones getting better at hi-res support (mostly on Android), but A&K keeps doubling down on performance and build quality, carving out space for the diehards who won’t compromise — and are willing to spend thousands of dollars on a wireless digital Walkman with almost unlimited storage.

The Astell&Kern A&ultima SP4000 isn’t just another shiny DAP to flex on your Discord server—it’s packing a serious upgrade under the hood. A&K ditched the old 1:2 digital-to-analog tag team used in the SP3000 and now rolls with a new 1:1 Octa Audio Circuit Architecture.

That means one AK4191 digital modulator is now matched with one AK4499EX DAC, giving each channel its own personal butler to handle the signal path—no more sharing, no more noise floor parties. It’s essentially a true Quad DAC, something that used to be considered impossible outside of a North Korean missile test briefing.

Most players mash their digital and analog signals together like a rushed buffet line. Not here. The SP4000 keeps things proper by splitting the digital and analog processing across separate chips, cutting down digital noise and letting the analog stage breathe like it’s on a weekend retreat in Cape Town.

The result? Ridiculously clean sound that might actually justify leaving your phone in your pocket—and, unlike certain dictators with inflated egos and terrible Wi-Fi, this player actually delivers.

Unlimited Power?

The Astell&Kern A&ultima SP4000 doesn’t just crank up the juice—it delivers it with the cold, calculated confidence of a man who skates like he’s late for a Rolex fitting, not Game 7.

High Driving Mode? Think of it as off-road mode for your audio. Two OPAMPs running in parallel gives the SP4000 a wider soundstage and more dynamic punch without dragging in extra noise or compromising SNR. It’s a clean, smart design move—less about flash, more about precision—and one of the few upgrades that actually earns its place under the hood.

Group delay—where different frequencies take their sweet time arriving—has always been a weak link in digital playback. Astell&Kern tackles it with their Enhanced Signal Alignment (ESA) tech, which keeps frequencies properly aligned so the timing stays locked in. The result? Cleaner imaging, better clarity, and a more cohesive soundstage that doesn’t fall apart under scrutiny.

And because noise is the enemy of good sound (and common sense), they tossed in an ultra-low noise LDO regulator. This thing cuts noise by 97% compared to earlier models, which is the kind of spec you’d expect from a surgical tool or some 5G tower melting your neighborhood birds. In short: the SP4000 doesn’t just play music. It bullies the noise floor into submission.

Going Full Android

The SP4000 finally does what Android audiophiles have been grumbling about for years: it goes full Android. And yeah, we all know the rule—never go full anything—but here we are, with full Google Play Store access baked in. No more sideloading APKs in the dark like you’re trying to sneak past security on Mustafar. It’s all legit now—every app, front and center, no hacking required.

But A&K didn’t just go full Android and drop the mic—they actually did the work. Their proprietary ADP (Astell&Kern Direct Path) tech gives Android’s dreaded SRC bottleneck the middle finger, rerouting audio like it’s dodging traffic on Sunset. So even when you’re knee-deep in Qobuz or TIDAL, you’re getting bit-perfect, lossless playback. Because let’s be honest—you didn’t drop a house payment on this thing just to have your hi-res tracks mangled like a bootleg mixtape.

Then there’s the second-gen DAR (Digital Audio Remaster) engine, now working in tandem with something called VSE—Virtual Sound Extender. VSE kicks things off by attempting to reconstruct lost harmonic detail before the audio even hits the upsampling stage, like it’s rebuilding the scaffolding of the original performance from the shadows.

Once that’s done, the DAR engine takes over for a second pass, upsampling with greater precision and nuance. The goal? A more natural, dimensional sound that pushes closer to what was actually captured in the studio. It’s not just signal processing—it’s a calculated assault on digital flatness.

Core Changes

The SP4000 isn’t just another chunk of steel with a DAC and a headphone jack—it’s a full-on engineering flex. Astell&Kern packed it with Any Layer HDI PCB tech, the same kind of ultra-dense circuit board design you’d find in high-end smartphones or defense-grade hardware. This isn’t overkill; it’s how you fit serious, low-noise audio circuitry into a compact player without sacrificing signal integrity. Signal loss, crosstalk, and layout compromise? Not happening here. It’s expensive, yes—but it’s the only way to build something this clean in a chassis this tight.

They’ve also thrown in a 99.9% pure copper shield can—because apparently 99.8% just wasn’t good enough. It’s the first time A&K has used this level of shielding, and it’s designed to shut down every bit of electromagnetic interference trying to sneak in and ruin your listening session.

And in case you were worried it might look like a tech demo from 2016, the SP4000’s new 4.5-gen user interface keeps the aesthetic in line with A&K’s usual crimson-soaked drama, now with a fancy LP animation that gives you the illusion of sliding a record across the screen. Because why just tap when you can feel fancy?

Let’s not kid ourselves—none of this comes cheap. But when you compare it to the new dCS Lina X Network DAC—which costs more and doesn’t even give you a screen worth looking at—the SP4000 might almost feel like a bargain. Almost.

The Astell&Kern A&ultima SP4000 is starting to feel like sprinting a marathon through the student library at Columbia, dodging performative outrage and overpriced oat milk lattes—all while someone tries to convince you this DAP isn’t just a glorified luxury item for people who think “streaming lossless” makes them superior. But here we are.

Let’s start with the Crimson Theme UI—A&K’s signature black-and-red aesthetic that’s supposedly easy on the eyes, battery-friendly, and designed around the principles of “Edge, Simple, and Sensibility.” Whatever that means, it looks slick, works well, and doesn’t get in the way. And yes, it still makes your iPhone’s music app look like Fisher-Price designed it.

The SP4000 ships with a Shrunken Calf leather case from Germany’s Perlinger tannery. We’re talking chrome-tanned hides from baby cows, shrunk with science (not heat) to preserve every grain and wrinkle for maximum luxury drama. It’s like wrapping your DAP in haute couture—a leather case with better pedigree than most of Wall Street.

Never Go Full Audiophile: What’s Under the Hood of the SP4000

Under the hood, you get 256GB of onboard storage and a microSD slot that supports up to 1.5TB, because apparently you need 4,000 albums on you at all times. Dual-band Wi-Fi, DLNA, USB DAC functionality, USB-C, and file transfer via AK File Drop round out the connectivity.

Want to play DSD512 and 32-bit/768kHz PCM? Of course you can. If you can find any albums recorded at those specs that aren’t absolute garbage musically, more power to you.

There’s also ReplayGain for leveling out volume across tracks, and a 6-inch 2160×1080 touch screen that makes the iPod Touch look like it should be in a museum. It’s overkill—but at least it’s well-executed overkill.

So yeah—this thing’s not just a DAP, it’s a full-blown audio command center wrapped in boutique leather, built for folks who can hear the difference between film caps and electrolytics in their dreams — all 3 of you.

It also now offers both aptX Adaptive and LDAC, meaning you’re getting real 24-bit wireless playback without the usual Bluetooth compression sludge. And with BT Sink mode, it pulls double duty as a high-end Bluetooth DAC—so your phone can stream into it while the SP4000 handles the heavy lifting with all its internal firepower.

Charging? Qualcomm Quick Charge 3.0 gets you topped up in about four hours, giving you around ten hours of continuous playback—which is probably just enough to get through a hi-res version of Wagner’s Ring Cycle… twice.

And then there’s Crossfeed—because apparently listening to perfectly separated left and right channels might melt your brain after a few hours. This feature blends a bit of each channel into the other with a slight delay, so it sounds more like a speaker setup and less like audio brain surgery.

Oh, and Roon Ready support is “coming soon,” pending certification. Because of course it is.

Comparison

But Why Sell My SP3000 on Audiogon?

Here’s the breakdown of what separates the SP4000 from the SP3000 and SP3000M—and yeah, this one goes to eleven.

The SP4000 finally cuts the leash and goes full Android with Google Play access, meaning you can install any app you want. No more sideloading APKs like you’re sneaking contraband into a high-security prison. The SP3000 and SP3000M? They’re still stuck in the Stone Age with a locked-down version of Android that feels like trying to get into a nightclub with a fake ID—everything’s heavily monitored and limited.

When it comes to the user interface, the SP4000 gets a much-needed upgrade with AK UI 4.5. It’s like they gave the old design a fresh coat of crimson paint and a smoother set of animations. It’s still the same basic layout, but now it’s a bit more polished and a little easier to navigate. Meanwhile, the SP3000 and M are still rocking AK UI 4, which feels about as current as your old flip phone.

The op-amp setup in the SP4000 is another step up. It runs dual op-amps in parallel, giving you more power and headroom to drive harder-to-please headphones without adding noise. It’s like giving a luxury car four-wheel drive—it’s overkill, but it feels good knowing it’s there. The SP3000 and M, however, stick with a single op-amp, which is fine but lacks the same muscle.

On the DAC side, the SP4000 doubles down with four AK4191 digital processors and four AK4499EX DACs, each digital processor dedicated to just one DAC. The SP3000 splits its digital processors, two per DAC, which is still solid but not as extra as the SP4000’s setup. If you care about your DAC configuration being symmetrical—and let’s be real, you probably do—the SP4000’s approach is basically the audiophile equivalent of “go big or go home.”

Bluetooth codecs get an upgrade too. The SP4000 swaps out aptX HD for aptX Adaptive, giving you a better dynamic range over Bluetooth, and it still supports LDAC. If you’re streaming 24-bit audio over Bluetooth and you’re still using old codecs, you might as well be listening to MP3s from 2005. The SP3000 and M are fine, but they’re lagging behind in this department.

Then there’s the second-gen DAR (Digital Audio Remaster) tech in the SP4000, which smooths out the upsamping process to make it sound more natural. It also gets Enhanced Signal Alignment (ESA) technology, which tackles group delay—basically, making sure all the instruments show up to the party at the same time instead of arriving fashionably late. The SP3000 and M? They’re still using first-gen DAR, and they don’t have ESA at all.

Power regulation gets a boost in the SP4000 too, thanks to a Low Noise LDO regulator. The result? Cleaner, more stable voltage, and a quieter background. In other words, your music will sound as crisp and detailed as possible without any unnecessary noise sneaking in. The SP3000 and M are good, but this extra level of polish takes the SP4000 into another league.

Finally, the screen: the SP4000 gets a big, beautiful 6” 2K display at 2160×1080, making it easier to read and interact with. The SP3000 is a little smaller with its 5.46” Full HD screen, and the SP3000M takes it down to a 4.1” 720p screen, which feels like you’re trying to navigate a touch interface with a postage stamp. If you like your tech to look as good as it sounds, the SP4000’s screen is a definite upgrade.

The Bottom Line

The A&ultima SP4000 will arrive dressed in your choice of black or silver 904L stainless steel—because obviously, surgical-grade metal is what your music player needed all along. Pricing and retail availability are still under wraps, but let’s be honest: if you have to ask, you probably already spent your disposable income on something boring, like rent.

But Wait… There’s More: Astell&Kern Gets Into Bed with 64 Audio

Astell&Kern isn’t just making noise—they’re teaming up with 64 Audio for a 10-driver IEM with an isobaric cone-to-magnet setup. Translation: serious fidelity, zero distortion. All wrapped in a polished 904L stainless steel shell with a DLC coating because luxury.

Oh, and Astell&Kern’s also launching Luna, their own IEM with a micro planar magnetic driver and a 20Hz–30KHz frequency range. Both IEMs are landing in Q3 2025, so start saving, or start pretending you don’t want them.

Price and availability. TBD.

Related Reading

• Astell&Kern A&ultima SP3000 DAP: Review
• Astell&Kern A&ultima SP3000T DAP: Review
• Astell&Kern’s New A&ultima SP3000M Flagship DAP is More Affordable