Aune S17 PRO Evo Headphone Amplifier / PRE – Culmination Of Power Delivery
Aune S17 PRO Evo is a $799 USD Headphone Amplifier that is a direct update from the original Aune S17 PRO that we have reviewed in the past. The new Evo version promises to fix the overheating issues that people have been having with S17 Pro, especially in warm environments, but there is also a sonic upgrade to be found with the new Evo version. Today we will review the new Aune S17 PRO Evo and see how it fits in today’s market, comparing it with other high-end amplifiers, including Sparkos Gemini (995 USD) and Singxer SA-1 V2 (599 USD).
Introduction
Aune is a high-end audiophile DAC / Headphone AMP designer from China, and their most recent headphones, including Aune AR5000 and Aune SR7000 have been some of the most popular models launched in 2024, but their Headphone Amplifiers have always been favorites of the public. While I’ve been doing my best to review every single one of them the original S17 has a tendency to run hot, so today we check out the S17 PRO Evo which should stay cool even with intense usage. We will put this to the test doay. As an Amazon Influencer, I earn from qualifying purchases, and using the purchase links in my reviews helps me maintain this website and Youtube Channel. Huge thanks to Aune for providing us with the sample for this review.
PROs – No longer does it overheat, and it can run basically infinitely at the maximum current and gain level. Thick, warm sound with excellent extension in the treble too. Sikly and velvety sound that is soft, warm, and pleasing even with aggressive music. Remote is a big bonus, and so is the ability to set the display to automatically turn off.
Cons – Altough it does not overheat internally, the chasis gets really hot still, at max gain and max current levels.
Product Link
Amazon – https://amzn.to/4jqbdaa
Aliexpress – https://s.click.aliexpress.com/e/_opCZE1X
Build Quality/Aesthetics
On a surface level, Aune S17 PRO EVO or Evolution looks exactly the same as the original Aune S17 PRO, with an arc design at the top, a large display on the front, and a large volume wheel that controls the stepped volume. We have three headphone outputs, including XLR Balanced, 6.3mm single ended and 4.4mm balanced for the headphone outputs.
To complement the already impressive design, Aune uses a Twin JFET, Aune’s Fully Discrete Class A Headphone Amplifiers, and an R2R Volume controller. We have two selectable current levels, and up to 7.5W of output power. The Twin JFET setup has a high input impedance and a rich, smooth sound. The temperature rise is the same, power and center voltage is stable, and it is the ideal input transistor for a headphone amplifier, per Aune’s design.
To keep up with the rising power demands from headphones like HIFIMAN HE1000 Unveiled and SJY Horizon, aune has two pairs of output transistors connected in parallel. The amplifier has a total of 16 output transistors, and the maximum output power is 7.5W. Aune notes that all types of headphones and IEMS can be driven without a problem, and to test this we have employed HIFIMAN Susvara, SJY Horizon, and for IEMs Sennheiser Ie900 and Campfire Bonneville.
S17 PRO Evo has a two-stage adjustment for the Class A current. Each channel has two pairs of transistors connected in parallel, so the quiescent current per channel can be up to 100mA / 200mA. The Class A circuit always amplifies, regardless whether there is a signal present or not. This current corresponds to the AC peak current. The no-load distortion is basically zero, and this is why Aune notes the S17 PRO to be an ideal amplifier circuit. We have XLR inputs and outputs, for the pre function, and RCA inputs and outputs.
To control the volume, aune employs the JRC R2R Volume controller, and the associated operational amplifiers to create a 4-way balanced R2r volume control. The display lets you know which current you’re using by being blue in color for the Low Current and Red in color for the High Current. There are also two gain levels, which is a separate feature from the current level. The low gain uses the transistors in linear operation, while the high current makes the amp give its all.
And the most important aspect of the Evo variant is the new Radiator structure. As Class A implies a high temperature, Aune employs a new 3D radiator, to match the high power delivery of the 50W toroidal power transformer. This transformer is coupled with a 19200 uF capacitor Array to deliver the best sound and stability possible. You can use both the included remote, but also the volume wheel to control most features of the S17 PRO, including setting the current level, gain level and other options it has.
Subjective Usage
Naturally, I found the original to run dangerously close to the maximum accepted temperature, and while it would not mean it is turning off when reaching that max T, it does turn to A-L or low current when that happens. The new, larger heatpipe actually removes this problem entirely, to the point where I got the S17 PRO Evo stacked with Dethonray Listening M1 on top, and a stack of two Topping B100 Monoblock Speaker amplifiers too, to create as much heat as possible. While my room is between 20 C and 25 C, I can confirm that even generating all the heat possible in the world, listening to HIFIMAN Susvara to almost max volume, and even using IEMs at high volumes, S17 PRO Evo did not run into overheating issues.
It does run much cooler too, around 62C at max in High Gain, High Current on my setup. Aune also allows you to set the screen to automatically turn off in the new S17 PRO Evo, and also you can have an independent volume control between PRE and Headphone AMP functions. You can select between the Headphone AMP and Preamplifier circuits, and engage each individually. To get all of this to work, Aune increases the total number of device components to 657 from the 635 found in the S17 PRO. For reference, the original S17 PRO would grow up to 67C in my home, and if it reaches 69C, it would automatically lower the current to protect its circuits.
I found the S17 PRO EVO to be as excellent as the original S17 PRO, no self noise with IEMS, including the most sensitive ones out there, and at maximum driving power, it can drive Susvara with ease, along with Audeze LCD-5, and all of the other headphones I have in my collection, including the mighty T+A solitaire P-Se. To really test the temperature situation, I have left the Aune S17 PRO Evo to play over a couple of nights – continously – using High Current Mode, High Gain and playing through a pair of IEMs – ThieAudio Origin – At low volumes. The maximum temperature S17 PRO Evo reached during this test has been 62C, regardless of the room temperature, and doing the test again but this time around playing with Susvara at medium volumes, I got the same result. I have to admit though, that we are in full winter in Romania and my ambient temps are around 20C, but still, there should be enough headroom to not run into overheating issues with any setup.
Sound Quality
Pairings – To test the Aune S17 PRO Evo I have used a collection of DACs, including Aune S9C PRO, Dethonray Listening M1, Musician Pegasus II R2R DAc, HIFIMAN Serenade, and EverSolo DAC-Z6. To test the limits of the headphone amplifier, I have paired the Aune S17 PRO Evo with a collection of headphones and IEMS, including Campfire Bonneville, Campfire Moon Rover, Simgot EM10, Soundz Flame, Westone Mach 60, Sennheiser IE900 and HarmonicDyne Devil. The headphone list includes Audeze LCD-5, HIFIMAN He1000 Unveiled, HIFIMAN Susvara and Susvara Unveiled, T+A Solitaire P-SE, Erzetich Mania V2024, MIRPH-1, and Audeze MM-100. S17 PRO Evo can handle all of those with ease, it never has to stop from using the A-H or high current mode, and the gain level low is actually mostly enough for all the headphones I’ve tested with it. Quite interesting, but the chassis grows quite warm during usage, yet the internal temperature stays much cooler than the original S17 PRO. This most likely indicates that S17 PRO Evo has a much better contact between the cooling heatsink and the metallic chassis leading to the improved cooling of the S17 PRO Evo.
Overall Signature – The sound of the S17 PRO Evo is quite a bit more dynamic and punchier than the original S17 PRO. We have a deep bass, a focus on the low-end and the lower midrange, but a better refinement and better revealing of the high-end detail and air, with the original having a slightly stronger treble roll-off compared to the Evo which seems to have an increased extension, although it still has the aune velvety top-end sound. The impact and control in the bass is incredible, S17 PRO Evo can pack a punch even with neutral sounding headphones. There’s an excellent sense of instrument separation and a serious depth to the sound, with the width matching the depth nicely, to create a huge soundstage.
Bass – You always start from the low-end, but aune puts a true emphasis on this low-end. Each song has weight, substance, impact and depth, S17 PRO puts the bass back into Susvara and Solitaire P-SE, it gives each song a thick, heavy outline and keeps an outstanding control, allowing you to hear an earthquakle level of sub bass and bass, without losing control. The basshead in me is super pleased by both the amount, but also the quality of the bass that S17 PRO Evo can create.
Midrange – We continue to a smooth, silky, warm and refined midrange. S17 PRO Evo has a bit of extra emphasis on the lower midrange, giving male voices weight, presence and a bit of extra oomph, while female voices also take advantage of this extra body, sounding full, pleasing and realistic, having the correct presence to them. There’s also a good sense of separation between instruments, between the foreground layer and background layers, and regardless of the music style you’re listening to, voices never get smeared with the instruments.
Treble – To complement the heavy and warm signature, S17 PRO Evo has a velvety, smooth and refined treble, but compared to the original, it seems to have a slightly higher level of energy and extension in the high-end. This means that most music is a bit more vivid, more engaging and has a higher contrast, so a higher resolution too when compared to the original S17 PRO.
Loudness Saturation Gradient – The loudness saturation gradient is an interesting subject, because the sound changes quite a bit between High Current and Low current, and also between high gain and low gain. Even within the same gain level, s17 PRO Evo seems to change the character with volume, and this is audible more easily with IEMS than large headphones, where the signature seems to be more consistent across volume levels and gain levels. The idea is that the louder you go, the higher the gain and the higher the current level, the more dynamic, more punchy, and more colorful the sound is, S17 PRO Evo likes playing the loudest it can.
Dynamics Handling – S17 PRO Evo sounds really colorful and contrasty, it has extreme dynamics that reveal even the finest of micro-details. S17 PRO Evo sounds intense and engaging, creating music that will remain with you long after you’ve turned it off.
PRaT / Textures – The trick to S17 PRO Evo and how it can be enjoyable is that it has a smooth texture level, it is basically smooth, full and the textures it presents are heavy, thick and warm. This means that even harsher songs are presented smoothly, enjoyable and easy to enjoy.
Soundstage – S17 Evo creates a wide, deep soundstage with a strong separation between instruments. Layering is excellent, and there’s a certain way S17 paints music that draws the foreground instrument in the middle, and everything else behind. While this can seem distant from my description, the engaging presentation makes sure that you’re never far from your favorite songs.
Comparisons
Aune S17 PRO Evo vs Sparkos Gemini (799 USD vs 995 USD) – Sparkos Gemini is by definition a single-ended only amplifier, but it has a tube PRE, and it is also known for being rather warm and smooth in the sound. The maximum driving power of Aune S17 PRO Evo is quite a bit higher, but Gemini is still mostly enough for the same headphones that S17 PRO Evo, including Susvara, Solitaire P-SE and even SJY Horizon. Sonically, the two are not that far apart, but there are a few key differences. S17 PRO Evo sounds warmer, thicker and has a higher amount of lower midrange, while Gemini has a more balanced sound with more treble, and more brightness in the upper midrange and the treble. Gemini creates a slightly more intimate soundstage from a depth perspective but it sounds wider, while S17 PRO Evo sounds deeper, but a bit more narrow in the width. Both have a high resolution, but they present other details, S17 PRO Evo renders the details in the lower midrange and bass exceptionally well, while Gemini renders the details across all sound more evenly. Both Amplifiers are excellent, and the build is great, but S17 PRO Evo will grow quite hot during usage, the chassis grows hot, while Gemini does not grow hot, but its chassis is has a bit of DIY flair, while S17 PRO Evo feels high-end and refined in the build. If you want the warmer, thicker and bassier sound of the two, go for S17 PRO Evo, it also has a lower noise with IEMs, while Gemini has a more colorful, even more contrasty and more balanced sound, although it has more noise with IEMs.
Aune S17 PRO Evo vs Singxer SA-1 V2 (799 USD vs 599 USD) – SA-1 V2 is a great amplifier that costs considerably less than Aune S17 PRO Evo, but also has a high driving power, and a similar sonic profile. The unit itself is quite a bit smaller, but Sa1-v2 still affords to be fully balanced, and it has basically the same inputs, outputs, but only S17 PRO Evo has a display, and a remote, both of which seem and are really useful, but not to the max, because a headphone AMP will not be as far away from you as a speaker AMP, since the cables of most Headphones and IEMS are quite a bit shorter. Sa1V2 does not have any overheating issues, it runs pretty cool, while S17 PRO Evo can get to 62C in my room and forced testing environment. Sonically, S17 PRO Evo sounds a bit more mid-centric, more balanced and has a higher level of detail, but also a deeper and warmer bass. In contrast, Sa-1 V2 sounds more balanced across the range, has a lower amount of bass, more treble sparkle and extension, but both are fairly warm, thick and beefy sounding amplifiers. Both have zero noise with IEMs, but the maximum driving power of S17 PRO Evo is quite a bit higher.
Value and Conclusion
For the price of 799 USD, you can have an amplifier that will surely never grow too hot, but will also sound excellent with both IEMS, but also the hardest to drive headphones out there. Also with zero self-noise, and outstanding control, and a silky smooth and warm tune, S17 PRO Evo is a nice refinement over the original S17, although if you don’t run into overheating issues, I wouldn’t upgrade from s17 PRO to the new Evo, I would purchase a new Evo if you need a powerful, beefy amplifier that can drive basically everything out there with no noise, but with an excellent control and high resolution.
Award – Before the end of today’s review I will be adding the Aune S17 PRO Evo to the Audiophile-Heaven Hall Of Fame for its excellent sound, reliable build quality, and now great cooling. It is the perfect match to the excellent S9c PRO DAC, and while for the AMP an evolution was necessary, it now delivers that warm, powerful sound without overheating.
At the end of the day, Aune S17 PRO Evo is a great amplifier, it does run warm and even hot to the touch, but the internals are kept in check, without the amp reaching dangerous levels. Even better, if you’re looking for a warm, silky, refined, but wide and contrasty sound, Aune S17 PRO Evo will deliver on those with a smile on its display-face.
Product Link
Amazon – https://amzn.to/4jqbdaa
Aliexpress – https://s.click.aliexpress.com/e/_opCZE1X
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Full Playlist used for this review
We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature. I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!
https://www.youtube.com/playlist?list=PL_cjBXGmwSHSdGcwuc_bKbBDGHL4QvYBu
https://open.spotify.com/playlist/5J3oloz8Riy9LxEGenOjQ0?si=979ba4f082414be7
https://tidal.com/browse/playlist/330fd544-8e5b-4839-bd35-676b2edbb3d5
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