Aune X1s GT

Aune X1s GT
The original Aune X1 was introduced over 11 years ago. Think about that, 11 years! Upon it’s release the X1 quickly became a fan favorite. It provided a strong Dac/Amp combination performance and to this day there are a huge amount of these in circulation. They’ve proven reliable, they sound great and Aune is still selling them well. With the Aune X1s GT we’re entering the 8th generation of this product. While from a glance each generation has shared the same shape internally there have been massive upgrades and complete redesigns over the years.

As a disclaimer I have no financial incentive or ties to Aune. This is the first product I’ve tried from them and I am not being compensated in any way for a positive review. I won’t pull any punches here. This unit has been toured and was also taken to a local Denver Head-Fi member meet with positive reception, I’ll lightly touch on some of those impressions below.

Fit, Finish & I/O:

For a low $300 product we’re looking at a pretty versatile all in one device. The Aune X1s GT has the ability to function as a DAC, Pre and fully balanced headphone amplifier which is above many other options in this price bracket. Starting with the rear of the X1s GT we’ve got both fixed and preamp out. I really like this design because I can control my monitors and also a secondary headphone amplifier if I want to share my music with someone else in the room or just try another amp. Not having to unplug and replug cables to accomlish this is is rather convenient.

Digital inputs are three in total. Optical, Coax SPDIF and USB. Additionally there is an additional input for an optional clock controller offered by Aune. Unfortunately, I do not have this clock on hand however, for a budget piece to have external clocking capability is a welcome surprise.





On the front of the X1s GT we’ve got an input cycle button that doubles as filter selection when double pressed – more on that feature later. We’ve also got the usual ¼ plug and a very welcome addition of a truly balanced 4.4 socket pushing out a healthy 1.2 watts per channel. Given the size of the unit standard XLR was not feasible however I prefer 4.4 myself as it’s such a sturdy connector. Aune also has a surprisingly high quality 4.4 to 4XLR adapter cable for near what the parts would cost to build it yourself, if needed.

When in use the potentiometer has an inviting red glow ring around it. My son was a big fan of this as it matched his gaming PC and made for a really pleasing aesthetic. Controlling volume for the X1s GT is an ALPS pot, I'm glad they avoided going digital control. Balance was fantastic through the usable volume range. The knob itself feels smooth and has great grip. I really like the notch and marker as it's easy to see in various lighting conditions especially due to the surround glow.

Finally, the X1s GT is housed in a solid piece of metal and is a very weighty unit for the size. One problem I have with smaller DACs or amps is with the unit sliding and tilting when plugging in or even when just adjusting the volume. The X1s GT stayed firmly in place throughout use even with all connectors in place on the rear.





Sound Quality:

When demoing the Aune X1s GT it’s easy to be distracted by it's size. Maybe we've all grown accustomed to the bigger is better mantra. At our local meet I went as far to tell users jokingly to just put up their hand to cover the unit from sight and just take in the sound. Despite it's visually compact first impression the X1s GT packs a serious punch from the balanced output. While the 1/4 lacks the significant power of the balanced socket it still retails the sound quality. When listening to the HD650 I was about 65% on the volume pot when using single ended, so it's not lacking or unusable by any means. Balanced just has a lot of current.

Perceived sound quality between the two outputs was undetectable for me.
I feel the auditory performance of the X1s GT is rather exceptional for the price bracket. Compared to my Jotunheim 2/Modius the X1s GT was far more focused. Bass is tighter and more 'true'. It's far less overwhelming. Authority without eggaguration. With Modius/J2 the dynamics can also be exaggerated and rather shouty. The X1s proved to be far more comfortable for longer listening while still retaining a strong sense of engagement. In this comparison it also doesn’t hurt that the X1s GT sports a much lower price point.

Compared to the Questyle CMA Fifteen the DAC section in the X1s GT is surprisingly competent. The tonality was largely similar from single ended while the technical performance of the Fifteen pulled ahead with it's 9038 Pro chip. When comparing them both as all in ones the Fifteen presented a larger soundstage with a more definined outline between instruments. Further improvements were present throughout the frequency range, as they should be for a flagship product however my positive impression always came back to the X1s GT's sharing of the same tonality. While it may lack the 'grand' presentation of the Fifteen I don't feel like I'm being short changed when I enjoy the X1s GT. It has an inviting sound that is either musical or detailed when called upon to do so.

I like to think of the X1s GT as a DAC/Amp combo that is suitable for any use. It absolutely excels at both gaming and music. This is something I’ve always had to use two setups for. I’d have a stack for music and one for gaming. With the X1s GT for the past few months I've been more prone to just turning one unit on and be ready for whatever I'm doing at my desk.

As far as perceived FR goes the bass is fast and crisp while still having an engaging thump thanks to it’s class A circuitry. The bass has a bit of warmth and great engagement factor. Mids are present but not overpowering, clear and mature thanks in part to the Sabre chipset. The sound is ever so slightly smooth so that the detail isn't overdone becoming eventually grating like in some units I've reviewed that have come from China recently. Highs are very smooth on the X1s GT and long term listening fatigue is very much on the low end. In my planars when the treble hits right the sound is instantly engaging and really gets my attention in a good way with great sparkle. The X1s's sound performance ticks so many boxes for me.

In terms of filters there is a Standard one for General & headphone use as well as Pure with the same set. Pure I believe lacks any shelfing – I preferred standard headphone for my K712's and Pure for HD650. The standard filter sounded great on my monitors. The best part about these filters though is that they were audibly different. Depending on what I tried I may prefer a different filter. Careful synergy has always been the most important aspect in personal audio. The X1s GT has the ability to insert itself in many different setups thanks to filters that actually matter. Some are slightly brighter, darker, etc. As far as playing well with sensitive gear I was pleasantly surprised with the lack of hiss when using the X1s GT with BA IEMs..

As far as weaknesses go, I can only identify one. The single ended output is indeed weaker than the balanced jack. While it had plenty of juice to power my 650’s if you were to use something like the HE-6se going balanced would be required. I did try this combo and was pleasantly surprised to hear them being driven convincingly. The X1s GT put up an impressive performance.

Conclusion:
Have a friend getting into the hobby who is asking for some recommendations? The X1s GT should be at the top of your shortlist. This unit is absolutely perfect for my son who is into PC gaming and is getting into music. Having it in has allowed me to both enjoy it's sound and share the hobby with him in a unit that isn’t overly complicated, bulky or intimidating. I love that I can route a pair of RCAs from the fixed output to another amp so we can listen to music together without fiddling cables. It’s proven itself reliable and drives every headphone we’ve tested it on with authority. It performed well with music, movies and games.

There is no doubt I could live with this unit as my main kit – It’s dethroned my DS Schiit stack in a pleasantly surprising way and sent it right to the FS forums. In a way it makes me reconsider what I ACTUALLY need on my desk when I've given so much real estate up in the past to sizable separates. Needless to say I give the Aune X1s GT a strong recommendation, absolute even when you start to consider the price bracket and form factor. It’s easy on the ears yet engaging and capable. Aune has delivered on the X1s GT - a really exciting showing at that.
-Vox



Bonus:
At our local Denver Head-Fi meet impressions for the X1s GT were quite positive. The sense of a surprising performance from a small unit was evident. Mentioned strengths were the X1s GT's well extended frequency range and engagement factor. Given all the gear available at the meet I was happy to see the X1s GT stand on it's own. For 99% of listeners, it's all you'll ever need.

The review sample was kindly provided by Aune in exchange for my subjective and unbiased review.
The selling price in Europe is €289 and you can buy it using this not affiliate aune-store.

Aune X1s GT

Aune is a pioneer brand with a huge range of desktop as well as portable audio gear.
The latest X1s GT is a revamped version of their classic X1 series of desktop DAC/AMPs, the 8th generation of the same.



PLL (Phase Locked Loop)

Aune X1s GT features PLL, a precise Phase Locked Loop digital clock algorithm that transfers appropriate frequency response data to the DAC. It maintains proper synchronization between all components in the audio chain.
Aune has also featured a 10MHz external clock input port for connecting external digital clocks, like Aune Xc1, and exploring more possibilities in sound.

The DAC chip

The DAC chip used is the ES9038Q2M which supports all high resolution files, up to PCM 32bit 768kHz and DSD512 via the USB input or 24bit 192kHz and DSD128 from the Coaxial and Optical inputs.

Instead of the seven embedded ES9038 low pass filters, the Aune X1s GT has its own specially designed filter modes with Aune’s self-developed algorithm. They feature two modes for general use, and two specifically for headphones.
Modes 1&2 are called standard while modes 3&4 are called pure.
1 and 3 are for general use while 2 and 4 are for headphones.



Fully discrete balanced amplifier

Aune X1s GT features an upgraded version of the company's classic B1 fully-discrete headphone amplifier circuit.
It uses 4x24 BTJs, 227 components in total and a positive/negative 9v power supply.
With the balanced 4.4mm headphone output, the X1s GT outputs up to 1200mW/32Ω of power while the single ended output is rather underpowered, maxing at 320mW/32Ω.
There is no gain switch and volume is adjusted by the means of a high quality potentiometer.



Low noise external power adapter

The unit is powered by an external power adapter.
Aune instead of providing the usually cheap generic power adapter, they have partnered with the famous brand MEAN WELL to include a specially designed low noise power adapter.



Inputs/outputs and operation

The X1S GT has three digital inputs (coaxial, optical and USB), and a BCN input for the external clock.
The USB input in addition to the Windows OS, it also supports Android devices and can be effectively used with smartphones and tablets.
There are two headphone output sockets, one single ended 6.35mm and another one, balanced 4.5mm. There are also two separate RCA analog outputs, the first one is fixed, bypassing the potentiometer for purer sound and the second one is variable for use with powered monitors and power amplifiers.



The power ON/OFF switch is located at the back of the unit while the front face houses the control button and the potentiometer which is illuminated by a circular LED around it.
The light stays constantly red and it doesn't change color according to the sampling rate which isn't displayed by any other means.
There are four small LEDs which are located next to the control button that are used to indicate the selected input method and the filter mode.
Pressing the button once will cycle through the digital inputs while a short double click will cycle through the available digital filters.
The filter choice is not displayed constantly so the user can't tell which one is selected and must rely on his memory.



Build quality and design

The X1S GT features the classic Aune, Arc-shape design which is quite modern and aesthetically pleasing.
The chassis is made from aluminium with excellent build quality and a rather flimsy painting.

About the PLL USB input lagging issue

There is a chance that the X1S GT while connected through the USB input might skip a few milliseconds of a track when you start playback or while listening to a playlist with various tracks of different sampling rates.
This is not something related to the other digital inputs.

This is an issue related to the PLL and it is happening only through the USB input and while filters 3&4 are selected.

Filter mode 1&2 also have very good PLL performance and the sound quality won't be degraded. It's just that if you pursue higher sound quality, you have filter mode 3&4 to choose from.

Here follows an official explanation from the Aune engineer.

"The protection of filter mode 3 and 4 is necessary, especially when the sampling rate is being changed - the PLL changes frequency until it's stable, during which, once random fluctuations happen, the DAC might output a big sound. Volume ramp up is to protect the devices after the DAC. Besides, the X1s GT supports a 10M external clock. If the external clock is warming up or the transmission cable is not well connected, within the time we set the X1s GT can react to that timely and close the output. At the moment, the output time we set for volume to rise from mute to 0dB is 800ms. Most music files have that room in the beginning. The X1s GT uses XMOS working in asynchronous slave USB mode, so to positively delay the computer end player data output, another big buffer needs to be added. Although the volume thing will be solved, there will be extra delay, like when you are watching a video, the sound might not match the picture.
Making full use of the PLL offers a high quality clock, which noticeably improves the sound quality, but at the same time, it will lose some speed of lock.
Filter mode 1 and 2 don't have that issue.
The USB receiving delay is within 2ms.
Most players have that buffer length setting, which is to avoid system crashes caused by frequent song changing. Usual setting is 500ms~1500ms.
So it is possible to adjust the buffer length and avoid the issue."

Power output

As per usual practice I left the X1S GT playing music for about 150 hours, prior to listening tests, without monitoring the progress.
I have used various headphones, from the similarly priced HiFiMan/Drop 5XX and Sennheiser HD660S to the Focal Clear Mg and HiFiMan Arya Stealth plus a couple of earphones like the FiiO FA7S and Dunu Falcon Pro.

The balanced output of the X1S GT is powerful enough to drive most of the headphones, with authority, good driver control and headroom to spare.
The amplifier stage is remarkably good, without audible distortion until you reach the upper limits.
The only case that you are going to reach for a more powerful, external, amplifier is if you own difficult to drive planar magnetic headphones.
But then you should probably seek for a different solution right from the beginning because, in my opinion, the X1S GT actual value is when used as an all in one device.
Powerful may be but the noise floor is still very low so it is pretty suitable for higher sensitivity earphones as long as you don't crank the volume to ear bleeding levels.
The single ended output is quite underpowered and the X1S GT really shines from its balanced output.



Listening impressions

The Aune X1S GT is musical and engaging yet not lacking in transparency and fidelity.
Frequency response is flat and well extended without any measurable or audible deviations from the reference linearity.
Yet the sound is by no means sterile or boring, the device is carefully tuned to be natural sounding and exciting with all kinds of music while it was a great match with all the headphones I used.
What stood apart were the textural qualities and the unique timbral characteristics.
It is pretty obvious that Aune has made a great effort in making the X1S GT sound as close to reality as possible and they have greatly succeeded in doing so.
I would attribute the excellent results to the combination of the discrete amplifier stage and the custom made digital filters.
I have tested a lot of gear with the ES9038Q2M DAC chip and the X1S GT is one of the least digital sounding ones, with minimal glare and absent of any treble harshness surpassed in this regard only by much more expensive products.
Indeed, the carefully implemented digital stage is feeding the custom made transistor amplifier, resulting in a full bodied, lush and well rounded sound with colorful harmonies and lifelike timbre.
Bass is full, visceral and hard hitting, it can truly impress the listener with it's contrasted dynamics.
Not the last word in control and timing, maybe a touch loose but still fast enough and well defined to handle everything with ease.
Mid-range is intoxicating, open and spacious with a velvety smooth texture, natural timbre and a fine articulation.
Solo voices are cunning while instruments of all kinds blend together in a communicative interplay.
Treble is smooth and easy going yet not deprived of energy although not as extended and agile as someone would expect from an ESS DAC chip.
This doesn't mean that it is lacking in airiness or detail retrieval and the truth is that you are not going to miss a lot while at the same time you are going to appreciate the different type of approach where the details are presented as an integrated part of the music rather than being projected in front of it.
Still if an analytical and brighter approach is more to your liking then there is a chance that you might not like the X1S GT.



Another striking effect that adds greatly to the naturalness of the sound is the textural evenness throughout the whole frequency range.
It is common for budget priced gear to exhibit some kind of unevenness regarding the overall textural balance of the sound with some loss of body weight and a faster decaying speed while climbing up the frequency ladder. This is something not true for the X1S GT which sounds absolutely balanced and with excellent coherency from top to the bottom.

The sound stage is well extended, quite open and spacious with sufficiently accurate positioning and good holography.
Highly communicative, the Aune X1S GT did a great job in preserving the ambience of recordings like in the following example where you can hear all the natural reverb of Berlin's Evangelisch-Lutherische Gemeinde “Zum Heiligen Kreuz” while enjoying the exceptionally natural timbre of the solo violin.



Non headphone use

This is a function certainly worth mentioning because the sound of the analog line output (fixed or variable) is of great quality, retaining all the excellent sound characteristics.
A great option for driving your powered monitors or substitute as a standalone DAC in a budget oriented 2 - channel speaker system.
The X1S GT is a great budget standalone DAC and should not be treated solely as a DAC/amp combo unit.

In the end

If I was to judge the X1S GT purely on sound quality criteria, then it would certainly be a five star rating thanks to the excellent, highly musical yet technically accomplished performance.
Unfortunately there are some minor - non sound related - issues that would not allow for the full rating.
If Aune could fix the PLL sync problem and have included a gain switch and some kind of sampling rate display then it would be perfect.
But then again life is too short to worry about stupid things and it would be a serious mistake to skip this excellent sounding DAC/amp just for this minor issues.

Test playlist

Copyright - Petros Laskis 2022.

Features
Has 4 different sound modes that actually make quite a difference and can help with headphone pairing and soundstage. Standard, Standard Headphone, Pure, Pure Headphone. To me the difference between standard and pure seems to be the high and low roll off point. The pure mode is the better sounding mode that allows more highs and lows but some headphones with harsh highs or overly boomy bass might be better tamed by the standard mode. It's worth trying both. With a good pair of headphones the standard mode sounds pretty digital due to the roll off but its great for cheaper headphones, gaming headsets etc that can sometimes sound way out of line on higher end or higher power gear. The difference with the headphone mode for each seems to be the soundstage presentation. The soundstage gains a bit of verticality with the headphone mode where it is pretty flat without it.


Sound Signature
Sounds very slightly warm. Has a high and low roll off on the very top and bottom edges and sounds a lot more digital if not in the "pure" mode. Nothing is really forward. Highs, Mids and Bass are balanced. Good amount of detail in lows mids and highs. This is one of the only units I've tried that doesn't really color the sound in any way. Its a very neutral presentation with a very slight warm bias. Has a wide soundstage but not much verticality. All of the sounds sit in the same horizontal plane. This is better with the "headphone" modes but not a strong point of this unit.


Build Quality
Over all feels solid. Almost has a rubberized texture. Does pick up dust and fingerprints as seen in the photos. Rubberized texture kinda holds on to some of the dust. Volume knob is nice and smooth. It kind of feels like one of those in between items. You can tell it's not something cheap or junky but it just doesn't quite have an ultra premium feel.

Issues
My review unit seemed to have an issue where it wouldn't come out of sleep if it wasn't used for a while when connected with USB. If there was nothing playing through it for around 45 min or so it wouldn't wake up without a power cycle. Not a huge deal but definitely something that can be fixed by the manufacturer with firmware updates.

Conclusion
Overall to me this is a well behaved and well rounded unit with good detail and a very slight warm bias. Very tame non fatiguing approach with no real outstanding characteristics to define the sound. Very easy to listen to for extended periods of time. Definitely recommended for the price