Review: New Toys from Astell & Kern A Promising Step Forward

Renowned Korean portable audio manufacturer iRiver has recently announced two new high-resolution Digital Audio Players under their Astell & Kern (A&K) brand – the A&norma SR15, and the A&futura SE100, to complement their flagship, the A&ultima SP1000. iRiver also introduced a new entry-level In-Ear Monitor, the Jerry Harvey/Astell&Kern Billie Jean.

This completes the rebranding of the A&K player lineup, with the A&norma representing the standard, entry-level lineup, the A&futura representing the premium, sub-flagship tiered players, and the A&ultima holding the spot for A&K’s flagship offerings.

I was recently at Smoke & Mirrors to witness the launch event, hosted by AV One Singapore, and got myself some time with both players, as well as the new IEM. What are the general features and specifications, and my initial impressions on the interface, sound, and how worth the entire package is? Read on to find out.

Firstly, the newest entry-level DAP from A&K, the A&norma SR15, is their replacement to the diminutive AK70. Launched in 2016, the AK70 was the answer to requests for a smaller, lighter, and more easily pocketable player than the older A&K offerings. Soon followed the AK70II, an improved and far more powerful version of its predecessor. Now, the SR15 will take over the AK70II as the baby of the bunch.

Here are some of the more important specifications of the SR15:

SR15 General Specifications

Display3.3 inch WVGA (480×800) TFT LCD
Supported Audio FormatsWAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF
Sample RatePCM: 8kHz ~192kHz (8/16/24bits per Sample)
DSD Native: DSD64(1bit 2.8MHz)
Stereo/DSD to PCM: DSD128 (1bit 5.6MHz)
Output Level (Condition No Load)Unbalanced: 2.0Vrms
Balanced 4.0Vrms
DACCirrus Logic CS43198 × 2 (Dual DAC)
DecodingSupports up to 24bit/192kHz Bit to Bit decoding
OutputsUnbalanced Phones (3.5mm)
Balanced Out (2.5mm, only 4-pole TRRS supported)
Dimensions2.26” (57.5mm) [W] × 3.92” (99.7mm) [H] × 0.63” (16.1mm) [D]
WeightAbout 5.43 oz (about 154g)
Battery3150mAh 3.7V Li-Polymer battery
MemoryInternal: 64GB [NAND]
Expandable by microSD up to 400GB × 1
WP Data Tables

SR15 Sound Specifications

Frequency Response±0.030dB (Condition: 20Hz~20kHz) Unbalanced
±0.024dB (Condition 20Hz~20kHz) Balanced
±0.080dB (Condition: 10Hz~70kHz) Unbalanced
±0.065dB (Condition 10Hz~70kHz) Balanced
Signal to Noise Ratio122dB @ 1kHz, Unbalanced & Balanced
Crosstalk137dB @ 1kHz, Unbalanced & Balanced
THD+N0.0008% @ 1kHz, Unbalanced
0.0009% @ 1kHz, Balanced
IMD SMPTE0.0004% 800Hz 10kHz(4:1) Unbalanced & Balanced
Output Impedance2.5mm Balanced Out (1.6ohm)
3.5mm Phone Out (1.1ohm)
WP Data Tables

Next, the A&futura SE100, is a mid-range DAP with near flagship specifications. It sits comfortably above the SR15 in terms of price and performance, yet doesn’t eclipse its ‘big brother’, the A&ultima SP1000. It sits where the older AK320 was in the previous lineup, but both stylistically and performance-wise, it is vastly different from its predecessor.

Here are the specifications of the SE100:

SE100 General Specifications

Display5-inch (720×1280) Touchscreen
Supported Audio FormatsWAV, FLAC, WMA, P3, OGG, APE, AAC, ALAC, AIFF, DFF, DSF
Sample RatePCM: 8kHz ~ 384kHz (8/16/24/32bits per Sample)
DSD Native: DSD64 (1bit 2.8MHz) Stereo / DSD128 (1bit 5.6MHz) Stereo / DSD256 (1bit 11.2MHz) Stereo
Output Level (Condition No Load)Unbalanced: 2.0Vrms
Balanced: 4.1Vrms
DACESS SABRE ES9038PRO 8channel
DecodingSupports up to 32bit/384kHz Bit to Bit Decoding
OutputsPhones (3.5mm)
Optical Out (3.5mm)
Balanced Out (2.5, only 4-pole TRRS supported)
Dimensions2.98”(75.8mm) [W] × 5.22”(132.7mm) [H] × 0.6”(15.2mm) [D]
Weight8.5oz (241g)
Battery3700mAh 3.8V Li-Polymer Battery
Up to 11 hours (Standard - MUSIC: FLAC, 16bit/44.1kHz, Volume 75, LCD Off)
About 2 hours charge time (9V/1.67A Fast charging)
MemoryInternal: 128GB [NAND]
Expandable by microSD up to 400GB ×1
WP Data Tables

SE100 Sound Specifications

Frequency Response±0.038dB (Condition: 20Hz~20kHz) Unbalanced
±0.028dB (Condition 20Hz~20kHz) Balanced
±0.074dB (Condition: 10Hz~70kHz) Unbalanced
±0.030dB (Condition 10Hz~70kHz) Balanced
Signal to Noise Ratio122dB @ 1kHz, Unbalanced
123dB @ 1kHz, Balanced
Crosstalk138dB @ 1kHz, Unbalanced
144dB @ 1kHz, Balanced
THD+N0.0007% @ 1kHz, Unbalanced
0.0006% @ 1kHz, Balanced
IMD SMPTE0.0006% 800Hz 10kHz(4:1) Unbalanced
0.0005% 800Hz 10kHz(4:1) Balanced
Output Impedance2.5mm Balanced Out (1ohm)
3.5mm Phone Out (1.5ohm)
WP Data Tables

Lastly, the newest introduction to the Jerry Harvey/Astell&Kern IEM lineup, the Billie Jean, is a dual balanced armature driver setup, featuring a rarely-seen “horn bore” design, and comes with a twisted silver-plated copper cable. The newest inclusion in the SIREN series of IEMs, the Billie Jean features the patented “Freqphase Time” technology, which minimises the phase shift of the individual drivers through precise tubing lengths. The two-way dual BA setup is customised to JH Audio’s specifications, and they sit one tier below the triple-driver Michelle. The Billie Jean is about 30% smaller than the Michelle, which bodes well for users with smaller ears.

Here are some specifications for the Billie Jean:

Billie Jean Specifications

TypeUniversal fit IEM
Driver Unit2-way 2×Balanced Armature drivers per side
1×High, 1×Full Range (Mid & Low)
Impedance18 ohm
Noise Isolation-26dB
Sound TechnologyFreqphase™ Time | Phase Waveguide
New Sound Bore
Components3.5mm Unbalanced Cable
3 Sizes of Silicon ear tips (S, M, L)
Carrying Case
WP Data Tables

First Impressions

Let’s begin with the new IEM, the Billie Jean. As the newest addition to the Siren series, I expected the Billie Jean to follow a similar style of tuning, one that is a mixture of dark and warm, especially present on the Michelle, their triple-BA offering. However, the Billie Jean was a departure from that trend instead, having a bright sound signature, something that might put off fans of the original Siren series tuning, but entice many more into the brand. Besides that, the Billie Jean has an upper-midrange emphasis, sounding especially sweet with violins and female vocals, and a nice amount of sparkle in mid-treble gives it an energetic presentation. However, there are a few weaker points, with one being the lower midrange, where male vocals sound rather thin and hollow, leaving a lot to be desired. The sub-bass extension on the Billie Jean was rather weak, having a nice midbass punch, but with almost no perceived sub-bass rumble, making it sound odd in the lower registers. The soundstage was decent, albeit on the intimate side, and details were very precise.

Overall, the Billie Jean is a decent attempt at the entry-level market from JH and AK, but there are areas where I feel it can be vastly improved on.

Onto the A&norma SR15, the AK70 successor. One of the more budget-friendly players around, the SR15 follows the trend of the AK70 and AK70ii, sporting a dual CS43198 DAC chip configuration, an upgrade over the CS4398 in the AK70ii and AK70. I won’t touch too much on the features or specifications, but it has all the usual AK features like WiFi connectivity, Bluetooth, Tidal streaming, USB DAC mode, Line Out, Optical, and so on. The interface of the SR15 is identical to the SP1000, and makes for a sleeker, more sophisticated look, and a far more futuristic feel than the older AK interface. The build is seemingly odd at first, but makes sense once you take into account the ergonomics of the player itself. The tilted display allows for convenience in achieving an “upright” screen – which may sound weird, but trust me, it works well. The volume knob itself is a piece of beauty, and the dark blue backplate blends well with the rest of the sleek black chassis.

As for the sound, fans of the dark/warm, smooth signature of the AK70 will be satisfied. Areas that I feel the SR15 improved over both generations of the AK70 are in areas like detail retrieval, soundstage, and a cleaner tonality. Soundstage, although not terribly wide, sounds more accurate, and as a result, imaging is also improved. Details are presented more clearly, although not a huge improvement over the AK70II. The SR15 still retains the quiet, dark background that pairs amazingly well with many sensitive IEMs, and the dark, smooth signature is non-fatiguing and pleasant to listen to. It’s a player that doesn’t seek to stomp on top-of-the-line offerings, but to instead make listening to music a pleasant and relaxing occasion. Overall, a very good choice that fares well against most mid-fi offerings, and provides a unique sound that fans of the AK tuning would love.

Lastly, the biggest toy of the lot: the A&futura SE100. This carries the torch after the previous mid-range offering from AK, the AK320. Like the SR15, the SE100 shares the new AK interface with the SP1000, contributing to the already sleek look of the aluminium chassis. Everything is built to look and sound impressive, and you have to really hold it in your own hands to get a proper feel for how impressive it is.

In a similar vein, the SE100 sounds rather like the AK320, with a major difference being a more energetic presentation, contrasting the smoother sounding AK320. The large change can be attributed to the new DAC ESS9038pro DAC chip it sports, instead of the dual AK4490 in the AK320. A slightly v-shaped tonality with a treble response that leans on bright, the SE100 is immensely resolving, precise, and has everything that will give you the cleanest, most accurate sound you can get in the entire lineup. If the SR15 is for casual enjoyment, and the SP1000 for flagship hifi-like sound, the SE100 is made for precision and detail.

Wrapping It Up

While I’ve personally never really been a huge fan of Astell&Kern players, barring perhaps the AK70, the new lineup is rather impressive. The range is a clear step into the future, away from their legacy days and products. I also look forward to the future A&norma, A&futura and A&ultima products. For now, this trio looks fit to succeed the lineup.

The Billie Jean, SR15, and SE100 are all available in stores such as Stereo Singapore, AV One, Jaben, E1 Personal Audio, Connect IT, and Music Sanctuary.

The recommended retail price of the SE100 is $2499, the SR15 at $999, and the Billie Jean at $529, with all prices including GST.

Visuals courtesy of Astell & Kern.

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