[anonbert]

Here are the internals of the S17 Pro on YouTube:

Some improvements that may lower temperatures would be:
3. Add thermal paste (such as CX-H1300 or Upsiren U6 Pro) to the bottom larger aluminum heatsinks (plate and bar)

I performed this task highlighted above two days ago and have documented my process here: https://imgur.com/gallery/pPL1fnQ

I have used the amp for over 24hrs and my unit can now stay at a constant 67 degrees without active cooling, but it still needs to be raised on tall feet.

 

[SmartCheetah]

I don't get it, my unit is much cooler than that without active cooling, only elevation. Today it's 24 degrees in my room, so not particularly chilly. It sits at 61 degrees after 5 hours on, stabilized after around 3h.

In the meantime, Aune Wuhan responded regarding the operating temperatures with just one sentence - it should be below 69. Duh!
Still waiting for Aune Europe.

 

[Giangi]

I don't get it, my unit is much cooler than that without active cooling, only elevation. Today it's 24 degrees in my room, so not particularly chilly. It sits at 61 degrees after 5 hours on, stabilized after around 3h.



In the meantime, Aune Wuhan responded regarding the operating temperatures with just one sentence - it should be below 69. Duh!
Still waiting for Aune Europe.

Imho and in my experience, it's not the external temp or other to determine the overheating...it's the headphone cable...

 

[Giangi]

I don't know for what damn reason, some cables overheat the amplifier. Maybe it's their composition or an impedance play, but it depends largely on the cable you use for the headphones, which can also cause other problems

 

[SmartCheetah]

Imho and in my experience, it's not the external temp or other to determine the overheating...it's the headphone cable...

I know. The length and possibly the materials might play a role. I have a rather cheap 1.4m Openheart balanced braided cable from Aliexpress, which is fine, but isn't exactly premium. Other headphones are used with their stock cables, which aren't anything special either. So, it's not just about pure quality. I tested 4.4 and 6.35 connections so far.

By the way, I'm going to test it properly when I have a chance. I'll cool the amp down to around 50 degrees, disconnect the cable, and check if it builds up the temperature to the same levels as with headphones connected. Results should be interesting.

 

[anonbert]

I don't get it, my unit is much cooler than that without active cooling, only elevation. Today it's 24 degrees in my room, so not particularly chilly. It sits at 61 degrees after 5 hours on, stabilized after around 3h.



In the meantime, Aune Wuhan responded regarding the operating temperatures with just one sentence - it should be below 69. Duh!
Still waiting for Aune Europe.

67 C was the max observed temperature after playing music for 24 hrs straight. I didn't monitor temperatures throughout the whole time, but know that it didn't go over 70 C since the unit continued to run at 100 mA at the end of the stress test. The S17 doesn't return back to 100 mA from 50 mA without user involvement as owners already know.

 

[SpiritualAbies2600]

I am going to see if I can exchange my unit as I think I got one that is overheating.

So I turned off the "mini fan" to see what happens... So in 100ma it hit 69 shortly then turned itself into 50ma. Just like 1st day it kept climbing, when it hit 73c, I turned it off. From everything I had read/experimented with, the unit should NOT go over 70c once it kicks itself back to 50ma.

At this time, I have tried 3 different cables (XLR, Pentacon, and etc). So I am considering mine one of the "bad" ones. I can definitely cool it way down with the laptop cooling pad, but I am worried about future warranty issues as mine wants to constantly climb over 70c without ACTIVE cooling even when it goes back down into 50ma mode.

 

[SmartCheetah]

@SpiritualAbies2600 I'm sorry, that must be frustrating. It's weird it keeps rising in 50mA mode.

For some comparison, also to @anonbert: 100mA, no active cooling. Low gain, volume range 12-38. The amp was on for the whole day, playing music. It stabilized after 3 hours at 61 degrees Celsius while I was using my planars and the balanced 16 core cable, and it did not go higher than that for the next 6 hours while I was listening to music and working. After that, I switched to my KZ ZAX IEMs with the stock 3.5mm cable, and the temperature went down to 60 degrees Celsius soon after. Then, I read your post, @SpiritualAbies2600, plugged in the ATH-MSR7b with the stock balanced cable, and also switched to 50mA. In 15 minutes, the temperature went down by 5 degrees to 55c.

I'm quite happy with the temperatures, but they differ significantly from yours, which is surprising. I have used a number of different headphones/IEMs and cables, but the temperatures seem to be rather consistent between them in 100mA.

 

[Erick Muller]

Open question to owners: In your own words and based on your experiences, can you describe the difference in sound quality between the 100mA and 50mA modes?

50ma is a more reference, neutral kind of sound that goes better with orchestral and live music or in case that a particular song was mastered to thick specially in the lower mids, bass region, it's better to use this mode because it can get to be a little bit too T H I C C (also depending the cans you are listening to) and also tends to a little bit more airy in the upper frequencies.

100ma mode is pure fun mode, the music gets denser and hits like a ton of bricks, specially when it's warmed up to above 60 degrees and it some instances seems to get a little bit more holographic in the soundstage, depending on the song and in some ways sounds more natural, specially in the vocals, it's just great that you have options with this amp in order to suit different tastes and cans.

 

[Erick Muller]

For some people, the mere fact that they would have to think about temperatures is too much and disqualifies the product. I understand and respect this.

The question is - do these temperatures lead to increased wear and reduced reliability? If not, why should we care?

In general and for me personally, it's not a problem. After lifting my unit, it stabilizes at 59-61 degrees after a several hours in 100mA. Is it too hot? I don't know, I do know it is still within 10°C headroom until thermal protection kicks in at 70°C. Which should have even more headroom before the components start to degrade, as is the case with any other heat-generating device, like graphic cards and CPUs.

I'm waiting for Aune's response about the optimal operating temperatures. I did my best to sound like I'm interested in their expert opinion regarding the class A amplifiers, rather than criticizing their product. So I'm hoping for an honest answer, not just some some marketing "pierdololo".

If they tell me it's best to keep it relatively low, then I'll use my USB fan placed underneath, which on the lowest speed is inaudible. Already tested it, and it doesn't exceed 50°C, which is just slightly warm to the touch and safe without any doubt. Again, some may say it's way too much hassle and bad design, and that's ok.

Otherwise, if they tell me anything below 70 degrees is 100% safe with reliability in mind, then i won't bother and just forget about the whole thing.

Also, while I don't want to use "but is sounds good!" argument - this is actually a fact that should be considered speaking about the product as a whole. As long as I'm confident the temperatures aren't a problem, I don't mind it being warmer than other amplifiers if sonic performance is superb and punches above its weight.

It would have to get substantially hotter before it becomes an issue with the internal components. If it was reaching above 80 degrees then at that point it might become cause for concern, the only reason the temps are an "issue" right now it's because for many people they're reaching 69 degrees to quick and it switches back to 50ma mode and the badly implemented R2R volume control and also maybe the 4.4mm in my case might be kind of faulty, but last time I used it, when I disconnected my headphones it may such a disturbing sound that I have only use exclusively the 4 pin xlr or the 6.35mm SE which don't present that particular issue.

So its far from being a perfect product but you'll be hard press to find a better amp under $1k usd.

 

[Slackaveli]

Most people, until now, didn't know about bias current in amplifiers.

yep. I would hope more add the feature.

 

[Erick Muller]

It's a shame, too, bc the manufacturers will just not give us 100ma and avoid all the negativity.

Why do people expect perfect products anyway? Especially considering thats-
A) Not even a thing and
B) they certainly have never created anything- usually at all- but certainly never anything even close to the perfection they demand.

You and I are on the MJ3 thread in this very forum and even this excellent amp has some flaws and some have even had to be returned to be fixed but people sing all the praises of the MJ3 because of the excellent SQ and for good reason, so if even Schiit with one of his top products is having issues with them, then we can expect issues with other manufactures too.

This of course shouldn't be use as an excuse or blank cheque for Aune for some of the issues that this amp legitimately has, including the temps, I too have issues with the fact that this amp is very sensitive to the HP cables you use, and the screen is subpar, the volume control is kind of crap, but this amp is build like a freaking tank, haven't had any issues with it(I come from a very negative experience with a schiit magni heresy that shorted it's 6.35mm connection and blew out the left earphone in one of my IEMs, and I still love Schiit), the temperature issue imho it's overblown, disregarding legitimately faulty units, if you run the amp on low gain, 100ma, you shouldn't have any issues if you raise the amp on some stands without having to use a USB fan.

 

[MiguelP]

Imho and in my experience, it's not the external temp or other to determine the overheating...it's the headphone cable...

Try without any cable connected and you will see...

 

[MiguelP]

I know. The length and possibly the materials might play a role. I have a rather cheap 1.4m Openheart balanced braided cable from Aliexpress, which is fine, but isn't exactly premium. Other headphones are used with their stock cables, which aren't anything special either. So, it's not just about pure quality. I tested 4.4 and 6.35 connections so far.

By the way, I'm going to test it properly when I have a chance. I'll cool the amp down to around 50 degrees, disconnect the cable, and check if it builds up the temperature to the same levels as with headphones connected. Results should be interesting.

It will. It's a class A amp.

 

[anonbert]

I have found that using the Susvara EQ presets with my HiFiMan HE2000 V2 (non-stealth) greatly improves the sound. Here are my Math Audio and PEACE presets in case anyone else wants to try:

PEACE download: https://sourceforge.net/projects/peace-equalizer-apo-extension
Add the SUSVARA.peace file into the config folder of Equalizer APO -- mine is located in C:\Program Files\EqualizerAPO\config and double-click the SUSVARA preset in the list below:

MathAudio Headphone EQ for foobar2000. Click "Load preset" and select the susvara_mathaudio.hdp file to enable the preset in fb2k.

Download: https://mathaudio.com/headphone-eq.htm