The Aune S17 Pro Evo was kindly provided free of charge in exchange for an honest review. I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links. The price of the Aune S17 Pro Evo is €839 and you can buy it from here.
Aune Audio
Aune Audio is a Chinese Hi‑Fi brand that creates desktop and portable DACs, headphone amps, music players, IEMs, and lately headphones, giving a strong focus on sound quality and thoughtful design. Their products are well known for being affordable while offering excellent value for money.
The brand has an extensive catalog of products but if someone was asked to name the most famous of them it would be the Aune S9C Pro, Aune S17 Pro, Aune AR5000 and Aune SR7000. Aune Audio has been extensively covered by this website, you can read all reviews by clicking here.
Aune S17 Pro flashback
The Aune S17 Pro is a Class A headphone amplifier that received great praise from reviewers and users alike because it offers superior audio quality at an affordable price. You can read the original Aune S17 Pro review here.
The amplifier had some minor functional issues that held it back from being perfect.
The first production batch had some kind of a volume adjustment glitch that was addressed and solved in the second batch. Aune Audio repaired or replaced all malfunctioning units at no additional cost.
The high temperature
The S17 Pro is a Class A headphone amplifier so it is perfectly normal to get very hot. Sometimes though, the high bias 100mA current mode can get the amplifier so hot that it can trigger the protection mode and automatically revert back to the 50mA bias. The amplifier has a temperature monitoring system that activates the protection mode when the internal temperature exceeds 69⁰ Celsius.
This is something that doesn’t always happen and it depends on various situations like ambient room temperature, the load of the amplifier, the length of the headphone cable and the placement of the amplifier. As an example, I have never experienced this issue as the working temperature of my amplifier never exceeded 67⁰ Celsius.
Anyway, many users have reported experiencing the high temperature issue and devised their own solutions by adding fans, external heatsinks or raising the amplifier higher to aid with ventilation.
Other known issues
The other known issues have to do with overall functionality. There is no option to switch the LCD display off or mute the volume. Furthermore, there is no option to switch between the headphone and the preamp line outputs. They are always active at the same time and inserting headphones will not mute the line output as it should happen. They also share the same volume setting so people that use them both must be very careful and always remember to unplug their headphones before raising the volume.
Aune S17 Pro Evo
Aune Audio after carefully considering all these reported issues, decided to fix them simultaneously and release an upgraded new version of the amplifier. Enter the Aune S17 Pro Evo, the same amplifier but with all known issues fixed. Well, except one as you still can’t mute the volume.
The main difference between the Evo and the legacy model is the much better thermal management through the use of larger heatsinks and more innovative circuit design to lower the working temperature.
Additionally, in the Aune S17 Pro Evo it is now possible to switch between headphone and line outputs while each mode has its own independent volume setting. Functionality is now restored and the Aune S17 Pro Evo functions as every other competitive device. Last but not least, the new model has a brand new LCD display with more vibrant colors and better visibility.
Technical highlights
The internal design of the Aune S17 Pro Evo is almost identical to that of the S17 Pro but for readers who are not familiar with the legacy model let’s remember its key characteristics.
The S17 Pro Evo is a true balanced, Class A headphone amplifier with two pairs of output transistors per phase connected in parallel so it has a total of 16 output transistors. The input stage uses twin JFET transistors that have a high input impedance that adds richness to the sound.
The amplifier features a user adjustable quiescent current between two values, 50mA and 100mA, while it offers two gain settings to allow better matching with different headphone loads. The S17 Pro Evo utilises a JRC R2R electronic volume chip to create a 4-way balanced R2R volume control for precise volume adjustment and zero channel imbalance.
We all know that clean power is essential for good sound. Aune Audio has paid special attention in the design of the power supply that is based on a 50W toroidal transformer with low ripple and 19200μF of total filtering capacitance. It is a dual power design where the digital and analog sections are completely independent of each other to minimize interference. Closer inspection of the S17 Pro Evo and S17 Pro internal boards reveals that the former has a redesigned power transformer and uses different capacitors in the power supply.
Design and build quality
Nothing has changed when it comes to the external design of the S17 Pro Evo which is identical looking to the previous model. It has the unique arched design of Aune’s S series with its plain and simple, yet aesthetically pleasing lines but the shape is not that suitable when you want to stack two units together.
The chassis is made from high quality aluminum alloy that is CNC machined and available in silver or black finishes. The faceplate is dominated by the central LCD display. At the left side there are the three phone outputs (4-pin XLR, 4.4mm and 6.35mm) while at the right you can see the aluminum multifunction knob.
At the rear side there are both XLR and RCA line inputs and outputs plus the AC inlet plug and the power switch. The unit doesn’t have a standby mode or a front power switch.
Build quality and finish are simply excellent, the Aune S17 Pro Evo is an exceptionally well made and assembled audio device without visible blemishes.
Operation
You can operate the device with the multifunction control knob or the small aluminum remote control that is included in the package.
A simple press of the knob alternates between XLR and RCA inputs that can be left simultaneously plugged in. A quick double press cycles between 50mA and 100mA quiescent current. You will have to press the knob continuously in order to enter the main menu where you can select the phone or preamp outputs, adjust the gain and set the screen timeout.
All actions can be conveniently performed with the remote control except selecting the output mode, a function that is only accessible from the multifunction knob. The knob is a little flimsy and I prefer to use the remote control when I have to adjust the volume.
Working temperatures
I have tested the Aune S17 Pro Evo and the S17 Pro side by side in order to monitor their temperature readings and find out whether they have been lowered on the Evo or not.
With both amplifiers switched on and idling without playing music for about an hour, the temperature readings were 44⁰C and 48⁰C for the Evo and the Pro respectively at 50mA quiescent current. These temperatures rose to 58⁰C and 62⁰C at the 100mA setting.
Playing music for more than two hours continuously at 100mA and low gain settings with the Meze Audio Poet, the readings were 64⁰C for the Evo and 67⁰C for the Pro model.
The ambient room temperature was 28⁰C.
It gets perfectly clear that the Aune S17 Pro Evo has better thermal management and runs 3 to 4 Celsius degrees cooler than the legacy model so it is unlikely that it will ever enter the overheat protection mode.
Power output and associated gear
With 7.5W/32Ω from its balanced output, the Aune S17 Pro Evo is a powerful amplifier that can run almost everything, even difficult headphones like the Hifiman Susvara.
The noise floor is exceptionally low for most loads but some background noise is slightly audible with sensitive earphones even at the low gain setting. However, I don’t count this behavior as a real con because I don’t see why someone would buy such a beast amplifier to drive sensitive earphones.
Except for the Hifiman Susvara, I have also used the Aune SR7000 and the Meze Audio Poet with Lavricables pure silver cables for maximum transparency. My main sources were the Aune X8 XVIII, Aune S9c Pro and the D&A Alpha Pro DAC.
Listening impressions
The overall sound signature and sonic performance of the Aune S17 Pro Evo is generally similar to that of the Aune S17 Pro except some minor differences that we are going to discuss later on.
For people who are too lazy to read the S17 Pro review, that also includes a comparison with the Violectric V222, here is a summary of the original text adapted to the S17 Pro Evo.
The Aune S17 Pro Evo is a standout example of an audio component designed not just to reproduce sound, but to express music with the soul and nuance of real instruments and voices.
From the first listen, it becomes clear how effortlessly music flows through this amplifier, rich with emotion, deeply engaging, and capable of forging a powerful connection with the listener. It’s an addictive experience, one that draws you in and rewards every moment with emotionally charged sound.
The sound quality is stellar, offering a rare combination of technical precision, transparency, and remarkably natural timbre. The technical performance might not be class leading but it is the timbre that is the defining trait of the S17 Pro Evo. It delivers an analog, organic quality that makes music feel alive, especially when paired with the right sources and headphones. The S17 Pro Evo performs with authority far beyond its price, matching effortlessly with higher-end gear.
More listening impressions
Tonally, it’s rich and full-bodied across the spectrum. The frequency response is linear, with a powerful, extended bass that is both visceral and controlled. It offers striking dynamic contrast, sounding fast but never rushed, and delivers clarity, layering, and resolution with ease.
The midrange is especially sweet, natural, and uncannily realistic, reminiscent of what vacuum tube designs achieve. It’s mildly warm without being dark or veiled and impressively clear and detailed at the same time, as a good solid-state design should be.
Instruments and vocals sound lifelike, textured, and full, with harmonic richness and colorful overtones. The midrange has both weight and precise articulation, handling everything from acoustic arrangements to vocals with grace and nuance.
Treble performance is smooth and refined, never harsh or fatiguing. It’s full-bodied and extended, energetic but composed, and luminous without being bright. The treble is marked by natural decay and realism, with no hint of artificiality or metallic sharpness. Detail retrieval is excellent, revealing fine nuances without tipping into an analytical or clinical character.
And some more
The soundstage is wide and well-layered, offering precise imaging and good depth, though not necessarily surpassing all rivals. However, its immersive, holographic presentation is a key strength, producing large, sculpted images that extend beyond the listener’s headspace, enhancing the overall realism of the musical experience.
The Aune S17 Pro Evo pairs seamlessly with a wide range of sources and headphones. Its versatile character suits nearly every genre, but it shines most brilliantly with classical music, where its natural timbre and spacious presentation truly come to life.
Honestly speaking, there are many rivaling amplifiers with a technical performance that mildly surpasses that of the Aune S17 Pro Evo. Models from SMSL or Topping easily spring to mind but none of them can touch the organic timbre and the sheer musicality of the Aune. These other amplifiers might offer better measured performance or sound more transparent and neutral but they are also too clinical and sterile in comparison to the S17 Pro Evo. There is no right or wrong here but users that seek for sound realism and harmonic richness should look for the Aune S17 Pro Evo and forget everything else at this price point.
Vs the Aune S17 Pro
When designing the S17 Pro Evo, Aune Audio has paid special attention to retain the same sonic characteristics with the original model. A/B listening tests confirm that the two amplifiers are almost identical sounding and share a similar, almost identical, sound signature.
However, there are some minor audible differences that must be attributed to the slightly different design of the power supply since everything else has remained the same.
The new amplifier is a bit cleaner and more transparent. The sound is just a little less warm and the textures are not as thick. The Evo model sounds more defined and textured, a touch faster and more energetic on the treble. The soundstage has enhanced inner spaciousness and the imaging is a tad more accurate and precise.
All other characteristics like the organic nature of the timbre, the harmonic richness and the deep musicality are the same. It would be safe to conclude that the S17 Pro Evo is the S17 Pro with just a touch more advanced technical performance and clarity but also a bit less warm and a tad drier. Still these differences are subtle and the general sound character remains the same between the two amplifiers.
In the end
In my original Aune S17 Pro review you can read “…the Aune S17 Pro is a hell of a surprise…it offers tones of musicality and realism…it will make your headphones shine and let your music flow as never before…” and “…don’t let the price fool you, the Aune S17 Pro is one of the best solid state headphone amplifiers your money can buy…” or “…an end-game amplifier, no matter how expensive your sources and headphones are…a miraculous achievement by Aune Audio that points to a brilliant future…”
My feelings are the exact same for the Aune S17 Pro Evo that is as good, or even better sounding, than its predecessor, while it also fixes the thermal management and functionality issues that were plaguing the first model and counted as negatives.
The Aune S17 Pro Evo is right now the best value for money headphone amplifier in existence, someone could even say a “giant killer”. A high-end amplifier at a modest price that you will have to pay at least two or three times more in order to find something marginally better. Aune Audio has improved an already excellent headphone amplifier with just a minor price increase thus keeping price to performance ratio as high as possible. If your budget is not unlimited and you still want the best headphone amplifier your money can buy, then don’t think twice, the Aune S17 Pro Evo ticks all the boxes.
Copyright – Petros Laskis 2025.
+ Excellent combination of musicality and technical performance
+ Very engaging and expressive
+ Natural and organic timbre
+ Holographic and immersive soundstage
+ Smooth sound without artificiality
+ Colorful and rich harmonies
+ Powerful output with low noise floor
+ Improved thermal management
+ Better LCD display
+ Remote control
+ Selectable phone and preamp outputs with independent volume
+ Automatic screen-off
+ Excellent build quality
+ Impressive price to performance ratio
- Can't switch output mode on the fly
- Can't mute the volume
- Audible noise with very sensitive earphones
- Can be bettered in objective technical performance
- Can get very hot - needs careful placement
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