Astell&Kern A&futura SE180 digital audio player

The first portable digital audio player I reviewed barely held a single album of MP3 music and it’d take half an hour to load up with even that tiny amount of music. Compare that with the Astell&Kern A&futura SE180 digital audio player. I have it loaded up with 1TB microSD card. It carries nearly 24,000 tracks, virtually all of them lossless and a significant number in high resolution formats – DSD, 88.2kHz, 96kHz or 192kHz PCM.

And it still has room for more.

tl;dr

• The Astell&Kern A&futura SE180 is a portable digital audio player
• It runs a heavily skinned version of Android – it may or may not run your favourite Android apps – see text
• Aluminium, stainless steel and polycarbonate construction
• 127mm full HD touch-sensitive colour display
• 5mm single-ended headphone output, 4.4mm balanced headphone output, 2.5mm balanced headphone output
• USB Type-C for charging and file transfer
• 256GB in-built memory, 1TB microSD card slot
• 5 hours playtime (16-bit, 44.1kHz audio at 50/150 volume level), 5 hours standard charging, 3 hours fast charging
• ESS ES9038PRO DAC
• Supports PCM up to 32-bits and 384kHz; DSD64, DSD128 and DSD256; plus WMA, MP3, OGG, APE, AAC and MQA
• Streaming services: TIDAL and Deezer, plus YouTube up to 720p.
• Output: up to 3V RMS unbalanced and 1-ohm output resistance, up to 4V RMS balanced and 1.5-ohm output resistance
• Removable DAC/amplifier module – optional Asahi Kasei based DAC module available
• 5mm by 137.3mm by 19.8mm
• 1 grams (including microSD card)
• The Astell&Kern A&futura SE180 delivers a magnificent audio performance in a highly configurable, highly usable package. Be prepared for a bit of weight, though.
• Price: $2499
• Available at fine high fidelity retail outlets, and direct from distributor's retail division here

More about the Astell&Kern A&futura SE180 DAP

It wasn’t that long ago I reviewed the Astell&Kern A&futura SE200 digital audio player. Clearly, the SE180 is in the same family, but while the SE200 packed two separate DACs and amplifiers, the SE180 has just one. But it’s one that you can swap.

When you buy the SE180, it is fitted with the SEM1 Amplifier Module, which employs a single the ESS ES9038PRO DAC. But if you prefer the Asahi Kasei sound, you can also purchase the SEM2 module which employs dual AK4497EQ DACs. That module is available here and is priced at $579.

But let’s go back to the SE180 in its standard configuration. The ES9038PRO is ESS’s premium model, with 8-channel, 32-bit support. The multiple channels are configured to improve stereo performance. Built into the chip are seven filter modes with the usual options for fast or slow roll-off and linear or minimum phase (the latter is known in some products as short delay). It’s interesting that ESS is still not offering an NOS mode – that’s a non-oversampling, non-filtering mode – that some listeners prefer. The default filter setting is Minimum Phase Fast Roll-off. I switched to Linear Phase Fast Roll-Off for my use of the unit, not because it sounded any different to me, but because on a technical level it provides the most accurate reconstruction of the original analogue signal (I explain all that stuff here). And isn’t that what high fidelity is about?

There are only physical three controls on the SE180: the power button on the top, the volume control on the right hand side, and a single control key underneath that. That key is for play/pause, but can also skip to the next track with a double tap, or to the previous one with a triple tap.

Of course, everything else is done via the touchscreen. The player starts up on the play screen, showing the last thing you were playing. You swipe down from the top for a quick menu for accessing Wi-Fi (2.4GHz band only), Bluetooth, EQ, USB functions and a few other things. You get to the main menu by swiping in from the left. This lists the usual ways of picking content – that is, via a list of songs, albums, artists, genres, playlists, genres. You can also enter via folder, or simply search for words. I entered “George” and within a few seconds the player listed 21 artists, 12 albums and 156 songs.

Also on that main menu you can get to “Services”, which by default include Deezer, TIDAL and V-Link. You can install others and, add later versions of, for example, TIDAL by installing an APK. Note, if you’re one of the many millions of Spotify users, you will need to install an APK. There is no guarantee that it will work, and Spotify does not provide support for its app when installed via APK.

There should be no need to install a different version of TIDAL because the pre-installed version supports MQA and gapless playback.

The V-Link streaming service gives you a choice of video or music. Choose video, and you’re presented with the alarming message: “The device supports video playback up to 720p. When playing video above 1080p, it may cause damage to the unit not covered by warranty.” I think I’ll stick to my phone when it comes to YouTube. After all, the sound quality on YouTube doesn’t really benefit from audiophile treatment. The music option seems to lead you to music videos from an uncertain source. You may have some fun playing around in there. My duty here extends to seeing if it works. It did. The few minutes I spent there did not suggest to me that I’d want to spend any more time there.

The Astell&Kern A&futura SE180 is incredibly versatile. Just dig around in the menus to see some of the things you can do. Here are a few:

• Use Bluetooth headphones, with better than usual quality due to AAC, aptX, aptX HD and LDAC codec support
• Equaliser
• Line Out mode – choice of four different fixed output levels
• Normal and high gain settings
• Can use external DAC via USB Type-C connection
• Can act as DAC for external device via USB Type-C connection
• Car mode (rotates screen for easier use in a vehicle, but do remember the road safety rules)

Using the Astell&Kern A&futura SE180

Initially I though the elimination of the separate skip keys would make the player harder to use, but I found that it was actually an improvement because with just one key, you don’t have to remember which key to press to play or pause.

The SE180 was quite weighty in my pocket. It’s 375-ish grams weight is about double that of many phones.

The only aspect of usability I would like to see improved is for an ability to increase and reduce the volume more rapidly. The volume scale runs from 0 to 150, and it takes a lot of turns of the volume control to get from one end of that range to the other. That said, clearly the company has to take care that an accidental flick of the volume control won’t drive the output level into the red zone.

UPDATE (a few hours later): Well, so much for that half-heated criticism. Later in the day I stumbled over how you can indeed adjust the volume very quickly. If you have the screen on, adjusting the volume control brings up a full-screen display showing what you're doing. While that's on the screen, you can adjust the volume instantly across the whole range by dragging your finger up and down the screen.

An illuminated ring around the volume control changes colour to indicate the audio format. But, really, if you want to know the format, just inspect the playback screen where the file codec, sampling rate and, for PCM, bit resolution are shown. These are also shown when playing TIDAL, including MQA colour codes. Indeed, the player also shows the unfolded sample rate and coloured authentication dot for MQA-encoded files played on the unit.

I’m generally happy with TIDAL as my music streaming app, but since I’m also subscribed to Spotify and Apple Music, I decided to give them a go. I could not get the Spotify APK to install. There were no such problems with the Apple Music one. I loaded it in, started it up, entered my login information and within moments was streaming. In its settings I chose Lossless, then High Resolution Lossless. With some tracks at 192kHz there was some breakup. I was uncertain whether it was an issue with communications speed or, possibly, the unit was underpowered to properly decode the Apple Lossless audio at such a high bitrate. I tried to crosscheck by using my regular, fairly powerful, Android phone, using the same external DAC I’d been using with the player to check the output. And with my regular phone, the DAC reported 96kHz, not 192kHz sampling for the same tracks. Weird.

Anyway, even when using the SE180’s internal DAC, the Apple Music app claimed to be delivering high resolution music. The only problem was that the app would start off with regular lossless playback – then after a while, realise it could handle high resolution, and switch to that mode – with a second of silence during the switch. Not the best way to enjoy music.

I used the Astell&Kern A&futura SE180 with lots of different sets of headphones and IEMs. For example, right now I’m using the Campfire Audio Honeydew IEMs. They’re very sensitive, and so fairly easy to drive, and sound delightful with this player. Last week I was using the 64 Audio Nio IEMs. They aren’t as sensitive and have a rather low impedance of just 6 ohms – well below the 16-ohms for which many headphone output devices are rated. The SE180 had no problems at all with those.

It was the same with several over-ear headphone models I used, including the lovely Final Audio D8000 planar magnetic models.

In all, the SE180 delivered an audio performance as good as it gets, and its headphone amplifier had plenty of output to drive all eargear to whatever level I wanted.

Some measurements

I ran some measurements using the 3.5mm single-ended headphone output. First, let’s consider what the SE180 can produce in terms of raw power. Into a 300-ohm load, it delivered around 2.9 volts, or in excess of 28mW. To be clear, that was in “high gain” mode, which I used throughout. That works out to be around 14.5dB above the plugged-in headphone’s or earphone’s sensitivity rating. You’re going to have to employ some very strange headphones indeed for this not to be an entirely satisfying level. With a mere 16-ohm load, the maximum output just short of clipping was 1.2 volts, which equates to more than 96mW. That’s close enough to 20dB above the sensitivity rating of the 16-ohm headphones or earphones in use. Again, you have plenty of volume even for low-impedance headphones.

I calculated the output impedance of this unit at 1.6 ohms on the single-ended connection, which means it should have good immunity to the variable impedance of headphones across their frequency range.

For the other measurements I set the output level to 1 volt RMS for a 1kHz full scale sine wave. That level is considerably greater than that likely to be used by the vast majority of users with the vast majority of headphones or earphones with the vast majority of music. With 24-bit audio the signal to noise ratio was consistently -117.9dB. With that result, it is simply impossible to discern equipment-produced noise. Total harmonic distortion – again with 24-bit audio – was just 0.00031%. IMD was a bit higher at around 0.006%, again well below the threshold of audibility.

With 44.1kHz 16-bit audio, the noise floor was at an impressively low -98.3dB A-weighted. THD was still just 0.00037% but IMD was up at bit at 0.027%.

Here's the frequency response with 192kHz sampling:

And here it is with 96kHz sampling:

In both cases, I’ve used the three different filter styles: fast roll-off (white), slow roll-off (green) and brickwall (blue). See here for a fuller explanation of the different filter types. If you’re a fan of flat, extended frequency responses, the Astell&Kern A&futura SE180 delivers with the fast roll-off. With 192kHz sampling, it maintains a ruler-flat output to 82kHz, beyond which there’s a sharp drop in output. Brickwall goes up nearly as high and employs a significantly sharper filter. You can see where the name comes from. Slow roll-off starts diminish at 67kHz and is down by 3dB at 86kHz.

With 96kHz sampling, the results are similar, with fast roll-off reaching out to 44kHz, brickwall to 41kHz and slow roll-off to 35kHz, to be -3dB at 43kHz. I doubt that you’re going to hear any difference between any of those.

I’d suggest, then, that you choose your preferred filter on the basis of regular 16-bit, 44.1kHz audio. That’s the format, I can say with confidence, of the great bulk of your music. And it’s the format in which the filter effects are most likely to be audible. Here’s the frequency response for that format for the three filters as implemented in this player:

Again we see the same pattern. Output is maintained solidly with the fast roll-off filters to 20kHz, falls a little short at 19kHz with the brickwall, and starts diminishing at 16kHz with the slow roll-off, to be -3dB at 20kHz.

Conclusion

The Astell&Kern A&futura SE180 is a first class portable digital audio player. The performance is brilliant. It supports all headgear that you’re ever likely to want to use. If you simply must use Spotify, it’s probably not for you. And I’d have doubts about Apple Music as well. But for TIDAL – and of course any music on a microSD card or in the player’s own internal memory -- the performance was absolutely rock solid, and the sound quality was of the highest order.