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Pros: R-2R discrete DAC, Class A and Class AB amp modes, NOS/OS modes, hi-res 5.46” display, updated fast user interface, 2.5mm/3.5mm/4.4mm PO/LO, MQA, DSD256, LDAC Bluetooth (both Tx and Rx), 256GB internal storage, hi-res analog sound with smooth detailed tuning.
Cons: price, case not included.
The product was loaned to me for the review purpose in exchange for my honest opinion. The review was originally posted on my site, and now I would like to share it with my readers on Head-fi.
Manufacturer website: Astell & Kern. Available for sale directly or from on-line retailers like Bloom Audio and Musicteck.
When it comes to Astell & Kern, their A&ultima (SP series) flagship releases are often considered to be early adopters of the latest AKM DACs, such as SP1000 and AK4497, SP2000 and AK4499, and SP3000 with AK4499EX/4191EQ. Then, their more budget-oriented A&norma (SR series) are optimized for portability and exceptional battery life while on the go. But it’s their A&futura (SE series) where you are going to find all the cool new features, like a dual independent DACs design in SE200 or a modular design in SE180. Thus, it came as no surprise when A&K announced their first discrete all resistor DAC design to be featured in SE300.
In addition to an all-discrete R-2R DAC, Class A and Class AB selectable amp modes, and NOS and OS oversampling modes, SE300 also features the same new digital platform as in their flagship SP3000 which includes faster processor and newly updated and more responsive interface. This all-new A&K DAP is going to make its debut at the upcoming High End Audio show in Munich. Luckily, I got a chance to spend almost a week with it, and now would like to share what I found. Originally, it was supposed to be just a First Look short review, but as I started testing, I ended up with a full write up of A&K SE300.
Unboxing and Accessories.
Since I received SE300 without the official packaging, I’m not able to share unboxing pictures, but was told the experience should be like their previous A&futura SE-series DAP releases. Thus, we should probably expect a more compact storage box along with additional accessories like screen protectors and quality USB-C high speed cable for charging, data transfer, and USB DAC functionality. I’m sure, a quick start guide, and a warranty card will be included as well.
One thing to note, SE series usually comes without a leather case. These DAPs are beautiful to look at and I hate putting them in a case, but I find it necessary to enhance the grip for a more secure handling, especially on the go.
With its dimensions of 139.5mm x 76.5mm x 17.6mm, SE300 is very close in size to its big brother, flagship SP3k, though it is lighter at about 317g vs 494g (SP3k). I wasn’t surprised here since they used the same size display and needed extra room for discrete resistors. The weight is probably lighter due to chassis material, which is a mix of aluminum and stainless steel, unlike SP3k which uses Stainless Steel 904L. At the time of the release, the only available color is platinum silver.
The focus of the design is still around a large 5.46" HD touch screen occupying the front view. This time, the front view of the DAP is more symmetric since only the right side has a slightly bulging-out area with a sculptured wavy design, just a bit recessed around the volume wheel. And just like in SE180, there is a separate power button at the top in the right corner, with a typical long press to turn the power on/off followed by confirmation to shut down or a short press to turn the screen on/off, though personally I like a double tap to wake up the screen. After using SP3k, I often forget and try to push the volume wheel, forgetting that SE300 has a separate power button.
The volume wheel is easy to turn using a thumb, though it's not loose and has some resistance with a click action felt with every rotation turn of 150 volume steps. Implemented here is also a multi-function LED behind the wheel to indicate charging status or bit depth depending on the source file (16bit – red, 24bit – green, 32bit – blue, DSD – purple). LED light could be disabled in Settings, and you can also enable/disable LED indicator light intensity as you adjust the volume. The design of the volume wheel has a unique crown pattern with a copper center, a design reminiscent of a wristwatch.
On the left side you have Play/Pause and Skip controls, three identical small rectangular buttons located in the upper part of the left side in the slightly recessed area. They do have a nice tactile response and spaced evenly with just enough room in between to avoid pressing an adjacent button by mistake, unless you have “fat” fingers. The top of the DAP has access to 3.5mm phone output port which also used for Line Out and Optical out. Next to it, you have 4.4mm and 2.5mm balanced phone ports that could also be configured for corresponding Line Out. All the way to the right you will find a power button.
At the bottom to the left, you will find a spring-loaded microSD card slot. In the middle, there is USB-C port, used for charging (including Fast Charging), data transfer, USB DAC connection, and USB OTG external device connection for digital audio out. The back of the DAP has a symmetric design with a carbon fiber back panel. Overall, the shape of SE300 is rectangular and the exterior design has less aggressive lines, not as flashy as their other DAPs.
Under the hood.
Unlike the traditional Delta-Sigma DACs from AKM, ESS, TI/PCM, or CS, SE300 uses R-2R Ladder DAC which is made of discrete matching resistors. There are different implementations of this design, and A&K settled on a fully discrete 24bit R-2R precision DAC which requires 48 pieces of resistors per channel, a total of 96 ultra-precision resistors. And these are not some generic off the shelf components, but rather matching parts with a high accuracy tolerance of +/-0.01%.
In addition to R-2R discrete DAC, A&K also implemented new dual amp architecture with a selectable Class A and Class AB amp modes. Plus, they utilized a selectable Over-Sampling (OS) and Non-Over Sampling (NOS) modes which have different sound processing implementation and reproduction. Furthermore, I was pleased to see 2 gain settings, Normal (NG) and High (HG), which could be useful when dealing with some sensitive IEMs. I will go over how I hear sound differences of these different options in the Sound Analysis section of the review.
Keeping up with their 2.5mm balanced “legacy”, just like SP3k flagship, SE300 includes all 3 headphones outputs, 2.5mm, 3.5mm, and 4.4mm. The single ended 3.5mm PO has output impedance of 1.3ohm and 2Vrms (NG) and 3Vrms (HG) and balanced 2.5mm and 4.4mm POs have output impedance of 1.3ohm and 4Vrms (NG) and 6Vrms (HG), with Vrms measurements based on unloaded condition. Each port can be switched to Line Out, and 3.5mm also has Optical SPDIF output.
The touch display is 5.46” HD with1920x1080 resolution, the same as in SP3k. The interface is very fast, like just in SP3k, noticeably faster than in other A&K DAPs. I didn’t see in the spec if this is the same Snapdragon 665 SoC as in SP3k, but I suspect it could be due to the same interface speed. This is still closed Android so it is hard to compare to other open Android DAPs since I can’t run 3D benchmark test app. There is plenty of processing power to do flawless audio decoding while supporting all the popular lossy and lossless formats, such as WAV, FLAC, WMA, MP3, OGG, APE, AAC, ALAC, AIFF, DFF, and DSF, with PCM rates up to 32bit/384kHz and DSD rates up to DSD256. Also, MQA playback support, covering Tidal Masters, Local files, External USB, and MQA-CD (ripped).
The internal storage is 256GB just like SP3k, and you also get microSD external memory expansion up to the latest largest capacity card (A&K tested with 1TB). I guess it doesn’t matter as much today since many people are streaming and high-capacity microSD cards are relatively cheap. Furthermore, USB-C OTG supports external hard drive storage or usb stick expansion. It even uses the same high capacity 5,050mAh (3.8V LiPo battery) and supports fast charging (QC3.0) to give you a full charge in about 3.5hrs (under 9V, 1.67A charging condition). I did run a battery test, and from 4.4mm bal output in High Gain with Class AB and NOS selected while playing hi-res flac files in the loop, I was getting about 11.5hrs of playback time with occasional screen usage to check battery status.
To support fast charging and to speed up data transfer, SE300 uses USB 3.0 Type-C interface for charging, data transfer, and USB DAC functionality. WiFi is dual band, supporting both 2.4GHz and 5GHz. Along with that you have OTA firmware update support and of course streaming of many popular apps. Furthermore, Bluetooth is up to 5.0 with a wireless support of not only aptX HD but also LDAC protocols for 24-bit playback over Bluetooth, plus both Bluetooth Rx and Tx.
When it comes to A&K DAPs user interface, once you are familiar with one, you will feel like at home using the rest because they share the same interface, down to their smaller display SR25 model. There have been small updates here and there, like a Floating Back button on a screen or playback controls when you swipe down notification bar while running apps. A few other Android related features were added in the past, but SE300 together with SP3k flagship takes it to the next level with a newly updated 4th generation interface that has improved ergonomics.
When you start the player, the greeting screen has a carousel where you can swipe through and access your songs in alphabetical order. It’s a fun way to view the song’s artwork along with other info, and it is very fast as you swipe through it. As you swipe right->left above or below the artwork of the song, you have Media Category Browser screen to view your Playlist, Folders, Songs, Albums, Artists, Genres, Favorite, MQS/DSD, CD Library, and then Settings and Category change to rearrange the order of the categories above as well as being able to disable Home screen carousel. Btw, when enabled, the Home button at the bottom of the screen takes you to this Home screen carousel, and every time you touch the Home button, it randomly brings up another song. I wish there would be a way to assign a different screen to Home button, but if you disable Home-carousel view and rearrange Media Categories, touching Home button will always bring you to the first selection in that list. I know, it is probably hard to visualize it by just reading this, but it is a lot of fun playing with it, especially since GUI is relatively fast.
All the way at the bottom of the screen you have 3 shortcuts buttons, Services (for easy access to all the apps), Home button which I already talked about before, and Back button, which is no longer floating while covering the screen, it is dedicated and always visible button at the bottom of the screen. Above it in the Main Home screen, you have a Playback control strip with a name of the currently playing song/artist and Play/Pause and Skip controls. Tapping on it brings up a familiar Playback screen window where the embedded artwork occupies top half of the screen and tapping on it expands the view and shows lyrics if one is available. Swiping this window down brings you back to the main Home screen. Below it you get a summary of song format (bit depth, sampling rate, file type) and a shortcut to tag the song as Favorite or another 3-dot shortcut with additional functions. Then, you have song artist/title and a scrub bar to advance through the song. Playback touch controls are underneath of that along with Play mode controls.
Swiping down notification bar gives you access to shortcuts to access various controls which you can toggle on/off or long press to get to their corresponding Settings screen. Here you have Wifi, Bluetooth, NOS/OS, AMP (Class A/AB), EQ, Car Mode, Line Out, Gapless, Wheel Lock, and Settings. At the bottom of open notification bar, you also have Brightness control. The full Settings window has more controls, partitioned in sections. Other controls you can find here are to select Bluetooth Codec, AK Connect and File Drop, L/R balance, Playback setting. Other usual controls for A&K CD Ripper, USB Mode and Audio output format, S/PDIF Conversion, Car Mode, setting Volume limit, enabling Double-Tap Screen to wake, LED indication options. And the typical date/time change, language and keyboard selection, timer settings, FW update, System info, and System Reset.
EQ is a big deal for some audiophiles, and here it hasn’t been changed. You still have one blank EQ preset and no other genre specific presets, and you can add many custom EQ presets. EQ interface has two modes: Main and Advance. In the Main you have standard Paragraphic EQ sliders for 20 bands (30, 45, 60, 90, 120, 180, 250, 380, 500, 750, 1k, 1.5k, 2k, 3k, 4k, 6k, 8k, 12k, 14k, and 18k) where you can either slide the bar or use a precise 0.1 adjustment, as well as scrolling through available frequencies. As you adjust, it gets reflected in the lower right corner, showing the overall shape of EQ. Switching to Advance, turns EQ adjustment into Semi-Parametric EQ with a full GUI view of EQ shape where underneath you have FREQ band selection (a choice of 20), Gain selection in 0.1 and 0.01 steps, and Q bandwidth. Since bands frequency is fixed, I consider this to be semi-Parametric EQ.
The sound analysis of SE300 was done using Aroma Jewel, playing a selection of test tracks, such as Agnes Obel “The curse”, Sandro Cavazza “So much better” (Avicii remix), C-Bool “Never go away”, Ed Sheeran “Shape of you”, Alan Walker “Darkside”, Galantis “Hunter”, Iggy Azalea “Black widow”, Indila “Boite en argent”, Dua Lipa “Love again”, Counting Crows “Big yellow taxi”, David Elias “Vision of her”, and Michael Jackson “Dirty Diana”. I had about 100hrs of burn in time before I started analyzing SE300.
I prefer to describe the DAP sound based on the comparison to other DAPs and pair ups with different IEMs/headphones since the DAP by itself doesn’t have a “sound”. What we hear is how it sounds through connected IEMs/headphones or the difference in sound relative to source comparison using the same pair of IEMs/headphones. This is my subjective opinion, describing how I hear it while analyzing the sound of SE300, and you will get a bigger picture about this DAP’s sound in the follow up sections of Comparison and Pair up.
In a summary, SE300 has a smooth natural tonality with an analog texture that adds a bit of warm coloring to the sound. It has a wide soundstage expansion, though not too wide or holographic, bringing the listener closer to the music, giving you a more intimate feeling, like you are a few rows away from the stage and the performer. The smoother analog tonality also yields a more natural layering and separation of the sounds, and by that, I mean not too much "air" between the layers. Despite smoother nature of the tuning, the retrieval of details is still very good, with the sound being quite resolving though not exactly micro-detailed.
With many IEMs I tested, the sound tuning does stand out with an excellent rendition of bass, enhancing its impact, weight, and texture. It doesn't just boost the lower end, but enhances its performance, especially when dealing with DD drivers. Also, I noticed with many IEMs the mids had a fuller body and a distinct analog texture. And the same with treble, sounding more natural, and a bit smoother to my ears. Furthermore, while I wouldn’t say the background was super black like in SP3k with details popping out of the blackness, it was dead quiet with sensitive IEMs even in high gain setting.
4.4mm/2.5mm vs 3.5mm – When comparing balanced versus single ended outputs, the sound tonality is identical. The only difference I hear is in soundstage expansion where the perception of 4.4mm and 2.5mm balanced outputs is wider than 3.5mm. As expected, 4.4mm and 2.5mm are the same. And another obvious difference is SE being less powerful, requiring me about 10 more clicks to match the volume of BAL output.
NOS vs OS - NOS gives the sound a smoother and more analog flavor. I went a dozen of times back and forth, and even in a blind test it is not hard to distinguish how NOS takes a digital edge off the sound, giving it a smoother tonality with a little more analog texture.
Class A vs Class AB - I hear a noticeable change in tonality and "speed" of the sound. Class A has a fuller body mids and more laidback sound with a slower attack, slower pace of the rhythm. When you switch to Class AB, the mids are a bit more revealing and the overall sound has faster attack, faster toe-tapping pace. I preferred Class AB with EDM, Pop/Rock, and any Top40 songs. For acoustic, instrumental, or classical music I like Class A setting. It will also depend on earphones and headphones and their pair up synergy with either A or AB.
Normal vs High Gain - the difference in volume is about 8 clicks. The sound change associated with a gain setting will depend on your earphones and headphones. With most of the multi-BAs or BA/EST hybrids it didn't make much difference. With some hybrids that included DD/BA/EST, high gain had a slight improvement in texture, though it could be related to an artifact of higher volume of listening. On the other hand, 470ohm ATH-R70x came alive with improved dynamics and tighter bass when switched to high gain.
In every comparison I used Aroma Jewel, volume matched while listening to the same test tracks between DAPs. Also, in this comparison I mostly focusing on the difference in sound as I hear it.
SE300 vs SP3000 - 3000 not going to be 10x better than 300 , but there are differences between the SP flagship and SE model. SP3k tonality is more neutral, the background is blacker, and the soundstage is wider. In comparison, SE has more analog coloring, not warmer by a margin, but smoother in comparison to SP. And the same goes for the background where SP is pitch black, while relative to SP the SE background is not exactly. SE soundstage is wide but not on the same level of width as SP. SE is more like a smoother and more analog tuned version of SP with a little more intimate presentation of the sound. Also, both share the same updated fast interface.
SE300 vs SE180 w/ESS board (SEM1) - Right away noticed a difference in soundstage presentation where 300 has more width and brings sound closer to you, while 180 has a narrower soundstage and extends the sound further out of your head. 300 tonality is smoother, more analog, more textured, while 180 is brighter, more revealing, and more digital in comparison. One thing that stood out was the punch and the extension of Jewel's bass with SE300 while with SE180 the bass was more relaxed, slower, and not as layered. I used SEM1 with ESS dac due to its smoother tonality in comparison to another SEM2 (w/AKM), but still, SE300 felt more analog and smoother in comparison. Not to mention that SE180 is built on an older SE platform with a slower processor and older interface, making SE300 operation a lot of faster and smoother, like SP3000.
SE300 vs Cayin N6ii w/R01 - A few differences in this comparison. While the soundstage expansion is not too far off, SE was just a touch wider in comparison with R01. Tonality of SE is a little warmer and smoother in comparison to R01. I also can hear a little blacker background with R01, but all these intimate comparison details will depend on the sound sig of your IEMs or headphones. For example, it was easier to pick up differences with Jewel, and not so much with RN6.
SE300 vs L&P P6 Pro - relative to testing and comparing with Jewel, their tonality is not too far off. P6 Pro is just a little bit smoother, but you can get close when switching SE300 from Class AB to Class A. Also, P6 Pro soundstage is a bit wider, and I did find P6 Pro to have a blacker background. And of course, even with its closed Android system, SE300 still has more functionality in comparison to audio playback only P6 Pro which has a more limited interface.
SE300 vs Hiby RS6 - Another R-2R comparison some might be interested in. From a soundstage perspective, I thought SE300 was just a touch wider. Other than that, they both have a similar technical performance, including a similar level of vertical sound dynamics expansion and the level of background blackness. But their tonality is different. RS6 is brighter, more revealing, while SE300 is smoother, with more analog texture, and warmer coloring.
SE300 vs Hiby RS8 - Decided to compare this one as well. Relative to Jewel, SE300 soundstage width is very similar, maybe with SE being even a touch wider than RS8. RS8 tonality is more revealing in comparison to smoother more analog tonality of SE300. I also noticed RS8 to have some improvement in vertical dynamics and layering of the sounds, but SE yields a much better bass impact, stronger and more articulate punch in comparison to RS8 having a little slower and more laidback presentation of the bass.
Here is how SE300 pairs up with some IEMs and headphones. In each pair up I noted my preference of gain setting and amp mode setting. All were connected using 4.4mm BAL.
FirAudio RN6 - High gain boosted the bass impact, pushing it more toward L-shaped sound sig. Then, Class A made lower mids thicker in tonality, taking away clarity from the mids. Thus, I preferred to switch to Normal gain and Class AB which made the sound sig more balanced, improving bass control (decay), and giving mids more clarity and better retrieval of details.
Aroma Jewel - Here, I preferred high gain over normal because it gave its DD bass more texture, tighter control, and better articulation. With amp modes, I thought that Class A sounded better due to more revealing nature of Jewel's tuning, but Class A took a step back in terms of resolution and made mids a bit smoother for my liking, so I switched back to Class AB for higher resolution and more precise layering.
EE Odin - This one was a bit of a surprise because I thought Odin's DD bass will be a perfect fit with High gain, but it made upper frequencies a bit piercing to my ears, so I switched to Normal gain which made upper mids and lower treble sound more natural in tonality. With Class A vs AB, it wasn't even a question, A added more warmth to the mids, giving the sound more organic tonality without compromising the resolution, so Normal gain with Class A hit the sweet spot with Odin to my ears.
UM Mentor Multiverse - here, either Normal or High gain made no difference in tonality, aside from me just adjusting the volume. So, either one is fine with MM. But Class A vs AB did make a noticeable difference, giving the sound a more laidback tonality with A vs "sharpening" the details and improving layering and separation of the sounds with AB. Also, with Class AB I can hear a bit more air in treble. For MM, I enjoyed Normal gain and Class AB.
Audio-Technica ATH-R70x - As I already mentioned, R70x came alive when switching to High gain. I heard improvements in sound dynamics, with more vertical expansion vs being a bit more compressed in Normal gain. Also, bass sounds tighter, faster, more precise in High gain. With amp mode selection, Class AB complemented nicely the High gain setting, improving the layering and separation of the sound. In comparison, Class A made mids a bit duller, losing some of the nuances in sound and having lower level of detail retrieval.
Meze Audio Empyrean - When it comes to full size and planar magnetic, you would assume that high gain will be better, but turned out that here it made no difference with either High or Normal gain, just had to adjust the volume to compensate for lower gain. But it made a noticeable difference switching Class A vs Class AB. Class A made mids a bit muffled and took away from clarity in vocals. Switching to Class AB improved the retrieval of details and "cleaned up" lower mids to give vocals better clarity.
Wired and wireless connections.
Besides being a portable DAP, you can expand SE300 functionality as a transport to drive external DAC/amp, to use external AMP, or to turn the DAP into wired/wireless usb DAC. And of course, you don’t have to be limited to wired headphones, and can take advantage of Wireless Bluetooth connection. Here is what I tested.
As I already mentioned, while SE300 has a closed Android system, you have a whitelist of available popular streaming apps to install. These are full app versions that look and function the same as if you would be running it on your Android smartphone or Android DAPs. Also, you no longer need to rely on a floating “back” button since this one is fixed at the bottom. Furthermore, while running streaming apps, you can swipe down the notification bar to see app’s playback controls.
I tested SE300 BT Tx with Final ZE8000 TWS and Hiby WH2, confirmed operation within 25ft, including full remote control. 25ft operation in open space was OK and the sound was the same as when connected to my S22, except I get close to 50ft when using it with my smartphone.
SE300 also has Bluetooth Sink Mode (BT Receiver) which sets the DAP as a wireless DAC/amp. Under Bluetooth setting of SE300, turn on Sink Mode and then scan for BT devices from your phone to pair up with SE300. Once connected, under the paired-up device on your smartphone click settings and turn on LDAC for SE300. The volume can be adjusted from both your smartphone and DAP, and SE300 will display the song/artists name, and I was able to control the playback (play, pause, skip) straight from the DAP.
USB Audio Out.
I tested and verified this one with various popular USB DAC dongles, such as Cayin RU6, Lotoo S2, and L&P W2, and found it to work flawless, just plug and go. Once connected, volume on SE300 is fixed at max 150, thus it is helpful to use external USB DAC dongles with their own volume control. The sound quality was no different than when connected to my Galaxy S22 phone.
Tested this one with my ThinkPad T480s under Win10. Once connected, by default USB mode is set to MTP so you can view the storage. In settings of the DAP, go to USB Mode and select DAC Input which going to activate USB DAC mode. Within seconds SE300 was recognized as AK USB DAC output in Windows sound settings, and I was able to control the volume from both, the laptop and SE300. The sound using DAP by itself vs USB DAC connected to the laptop was the same.
Was using iFi micro iDSD BL for this testing, nothing needs to be selected or enabled, just connect optical cable to 3.5mm port and start playing. Optical output was detected automatically, SE300 volume was set to max 150, and I was controlling the output from micro iDSD. Other than that, no surprises using SE300 as a transport to drive the external DAC/amp where I’m hearing a typical micro iDSD tonality.
I tested LO with Cayin C9 amp. Just connect either SE or BAL outputs, select Line Out from Notification bar shortcut or go to Settings, and under Line Out option select the output voltage level where you have 4 choices of unbal/bal: 0.7V/1.4V, 1V/2V, 1.25V/2.5V, or 2V/4V. Then, as you turn the volume wheel, you activate Line Out by switching it to a fixed voltage output. The volume was adjustable from C9 amp.
As I already mentioned in my other DAP reviews, we are at the point where it is hard to come up with groundbreaking innovations, and there is no longer a huge gap between mid-fi, upper mid-fi, and summit-fi audio performance. When it comes to Astell & Kern and their flagship A&ultima (SP) releases, their focus is more on fine tuning improvements rather than drastic changes in sound or the design. On the other hand, their A&futura (SE) series became a platform for cool new features you won’t find in A&ultima. This was the first one for A&K, stepping away from a traditional design with Delta Sigma DACs, and switching to an all-discrete resistor ladder design of R-2R DAC, complemented with Class A and Class AB amp modes, and even NOS to bypass the oversampling.
It's not the first DAP to implement these features or R-2R discrete resistor DAC design, but it’s one of the first A&K DAPs with such a plethora of sound tuning options that was truly a fun to play around with as I was switching between Gain settings, Amp modes, Oversampling and Non-Oversampling to find a sweet spot while fine-tuning the natural analog tonality of this hi-res DAP in search of the best pair-up synergy with my earphones and headphones. SE300 will appeal not just to diehard fans of A&K DAPs, but also to many other audiophiles looking to complement their one-trick pony sources with something different and more fun. I think even SP3000 owners will find SE300 quite appealing.h
When you are not basshead, that boosted bass with extra impact and weight can be problematic with already bassy iems.