[Erick Muller]

Summer is soon enough, so we'll see. The most temp I had in my room this year was 24 degrees, and my unit didn't exceed 61 degrees with 100mA as I reported there. Summers were quite hot in the recent years though, easily exceeding 30 degrees, so I'm curious how this will affect the amp.

I notice that in recent days, since temps are starting to rise up where I live, the amp has also gotten warmer, just a couple of degrees, but spring hasn't arrive yet and summers can get quite wild where I live so we'll see how this amp handles it.

 

[Erick Muller]

That is not how amplifiers work.
The RCA inputs will go through a phase splitter to be converted to balanced for the circuit. The only thing you might lose is some gain (so you'll have to turn the volume higher), but that's not power. It's the non-balanced headphone output that only uses half the amplifier, and wont have as much power, which is what you see on the spec sheet.

Thanks for the correction Mr. Currawong.

 

[MiguelP]

Some thoughts about the signal levels. This is important I guess only, if it's so and so, is there enough headroom to use. Ain't it so that e.g 5.0 v balanced output signal is twice the level of 2.5v output signal usually unbalanced rca. If I understand right, from headphone output, balanced or SE, 5v signal sounds 3 db louder than 2.5 v signal.
In this thread has been a lot of talk about Aune's heating up. So when operating with higher power output levels I guess this 5v - 2.5v difference might be of real importance. E.g is Aune working with 2 w rms or 4 w rms levels. Ain't Aune getting hotter and quicker hot when using double power?

No. The unit actually gets more quickly to 69 C just turned on with no signal whatsoever (no cables connected). If you use it with more demanding loads it theoretically dissipates more heat - that's the principle in a real class A amp.

 

[Erick Muller]

Thanks to everyone for getting back to me on the different questions.

@Currawong That's really useful feedback good sir here. If from what you are hearing, the M19 is fairly close to the S17...That is something definetly to keep in mind. Again, I like warm type of amp and it is in Europe for 300 euros more...But if I can leave the amp in the best conditions on most of the time, that is an option to keep in mind. I think you are working on a review for this device? Really interested to see how you will approach this 50/100ma thing. What do you think on the difference of sound? do you hear something significant on your end?

For the fan, does anyone would be kind enough to link what fan and AC (adapters) and variable rate they are using?
I will think to get this for myself and see what we can do.

The bass though on this amp at 100ma is really great and impactful! My HD 650 and LCD 2C really sings on this amp...
Aune did a great job disging the amp itself...too bad they didn't work out the cooling design.

Personally, I feel the 50 ma sound is a bit more brittle in the treble region and bass lose some of its heft.
As always, it is not night and day of course but I think if we are in this gig, we are after evertthing we can get from the hardware so...it is a bit frustrating to work in 50 ma when you do enjoy the amp at 100ma...

Thanks again for your feedback.

I recommend this usb control fan, that's what I've been using,
https://www.amazon.com/gp/product/B07TMBSN4G/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&th=1

The problem with this is that you're going to need a way to elevate the amp over these fans in order to cool it properly from underneath, which is the most efficient way to control the temps on this amp. So I also recommend you get this monitor stand and put the amp on the top rack and the fans in the lower rack, since the metal sheet of the rack it's perforated, airflow it's not restricted to cool down this amp

https://www.amazon.com/gp/product/B07VN9T173/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&th=1

I also use these speaker feet to elevate the fans and put them closer to the underside of the amp.

https://www.amazon.com/gp/product/B09QC2L7N3/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&th=1

The first thing that I would try tho is to try to rise the amp up with the speaker feet, if this proves to be enough in your case to keep the temps inside of the amp under control, then you shouldn't worry about getting a fan to cool it down, also make sure to keep your amp in a well ventilated area and in combination with the speaker feet, that should be more than enough to keep this amp cool and under control. YMMV tho.

 

[Erick Muller]

Well, yes and no. I still wouldn't describe the NYC area as exactly warm ATM, but external temperatures in the last couple of days warmed to around 70°F or roughly 21°C (they are expected to decrease to more normal March levels this week). The S17 has been heating up noticeably faster, though it still takes a couple of hours or more to reach 67°. At that point, I turn the three speed 120mm fan I have on top of the S17 on at low (it's inaudible to me unless I put my ear within a couple of inches with no music playing) which cools it down to below 60° in around twenty minutes, at which point I switch it off.

I would recommend that you try to put the fans underneath the amp since that's where the main heatsink of this amp is located at, and elevate the amp above this fans so you get the most optimal airflow, when I get to 67 degrees I only need to turn on my fans to the lowest setting and in less than 15 min I'm under 60 degrees, again YMMV but I think this would help in regulating the temps of your amp, I'm aware this may be to cumbersome for many people, but unfortunately Aune didn't do a great job with temp management on this amp it seems from the many reports we're getting.

 

[Erick Muller]

I just want to update my post :"D. My S17 doesn't have any heat issues, the device still operates fine at 100mA for 4-5 hours. I'm not sure if my device is the latest manufactured, but this is the firmware displayed in my S17. For those who don't know, you can hold the volume button and power on the device, then the firmware will be displayed :"D

This is another firmware update it seems, mine it's from around October last year, so maybe the change something.

 

[Erick Muller]

Now, that is interesting!



I have the 2023.10.19 V5.3
I don't have the volume problem....or at least this is not much an issue for me.
But yes I have the heat issue....
@huyrua811 , you don't use any fan or specific manipulation to keep the amp cool?

I assume the firmware requires some factory or sellers update as there are no USB ports for this....
Really thinking more and more to send back my device.

@AuneAudio we would really like some comments on this for customers having old firmware like mine and what is best to do.
I suppose I can raise a case directly to Aune's support...

I think I have the same firmware as you, I don't have the volume issue either, the temps, well I'm doing stuff to keep it manage, but I rarely have to turn on my fans on, but I do have a large window right in front of my audio setup so I get pretty good airflow to my amp, something that I know not many people are going to have.

 

[risingsun1981]

Hi everyone,

Nice to see a very active forum trying to work out this nice amp.
Again, it sounds great and I feel the 100ma does help the sound toward my preference...hence the idea to keep it working this way.

It is, I tried to find some pattern, but it seems completely random.

@risingsun1981 When did you buy your unit? Mine was bought in December, no idea when it was produced though as it has the October firmware. (How many versions were there?) My last guess is they did some kind of ninja-improvement of the cooling system near the end of last year.

But if someone shows up with a heating problem and the latest firmware, then I give up.

@SmartCheetah I just got my unit last week!
But who know how long was it in the stock of the reseller...
I do have a serial like S172405XX...for what it is worth.

I am still wondering if I should:
1 Just deal with it and use the excellent feedback from @Erick Muller to get the right hardware to keep the temp low
2 Give a shot and exchange with another model and just hope it will have improved status
3 return this amp and add a bit more to get an AudioGD Master 19...
Or 4 Open a case with Aune? Did someone tried this already for this issue?
though I have a hunch they may say this is as per normal operation....

I recommend this usb control fan, that's what I've been using,
https://www.amazon.com/gp/product/B07TMBSN4G/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&th=1

The problem with this is that you're going to need a way to elevate the amp over these fans in order to cool it properly from underneath, which is the most efficient way to control the temps on this amp. So I also recommend you get this monitor stand and put the amp on the top rack and the fans in the lower rack, since the metal sheet of the rack it's perforated, airflow it's not restricted to cool down this amp

https://www.amazon.com/gp/product/B07VN9T173/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&th=1

I also use these speaker feet to elevate the fans and put them closer to the underside of the amp.

https://www.amazon.com/gp/product/B09QC2L7N3/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&th=1

The first thing that I would try tho is to try to rise the amp up with the speaker feet, if this proves to be enough in your case to keep the temps inside of the amp under control, then you shouldn't worry about getting a fan to cool it down, also make sure to keep your amp in a well ventilated area and in combination with the speaker feet, that should be more than enough to keep this amp cool and under control. YMMV tho.

Thanks for this @Erick Muller ! That are some great pointers to get the right stuff.
I got the idea and that looks easy enough. I guess the fans you are pointing too, when in lower speed, are pretty silent so, that sounds like a good compromise.

I will keep thinking.
Since I have bought the amp online in Europe, I have still a bit less than two weeks to return it if not satisfied.

Cheers everyone for taking the time to get back to me and wishing you all a good day.

 

[Marlowe]

I would recommend that you try to put the fans underneath the amp since that's where the main heatsink of this amp is located at, and elevate the amp above this fans so you get the most optimal airflow, when I get to 67 degrees I only need to turn on my fans to the lowest setting and in less than 15 min I'm under 60 degrees, again YMMV but I think this would help in regulating the temps of your amp, I'm aware this may be to cumbersome for many people, but unfortunately Aune didn't do a great job with temp management on this amp it seems from the many reports we're getting.

Uhh, why would I want (or need) to do that when (1) it is not only more convenient just to place the fan on top of the S17, but impossible to place it underneath in my situation without some kind of major investment of inconvenience, time and/or money (the details of which don't even begin to present themselves to me) and (2) the fan on top at its lowest setting immediately begins to lower the temperature and it decreases from 67° to below 60° in about twenty minutes (yes, it will eventually get warmer here, but I'll be able use the AC by then which will get the temps in my apartment to roughly what they are now).

 

[stevedlu]

The units in warm places are the ones that overheat. Each owner can simulate the effect that a few degrees increase or decrease in the room temperature can have in the unit temperature - I've done it months ago. If I was in Sweden (for example) right now I'm pretty sure that my unit wouldn't overheat.

nope, thermostat set to 67degrees with a fan overhead when it only lasted 30min, it was very chilly. Oh and it has 1inch raised feet.

 

[stevedlu]

deleted

 

[stevedlu]

Please give us an update once the amp has broken in and after it's been switched on for an hour prior to listening. I'm interested in maybe this or the TA-20 Plus so I'd love to hear your views on the TA-22 comparison

No problem. I'll check back in. The TA-22 is the best $500 i've ever spent. I wasn't looking for an upgrade but just a second rig for the office and wanted to try something different hence the S17pro. I would have saved a lot more money just buying a second one for the office. With RCA tubes it's the best sounding rig I've ever had, the DAC is killer on it.

 

[stevedlu]

This is interesting, I put a laptop cooler and its stable at 56degrees in 100ma (just during burn in, the fans are too loud for reg use)...I just got some new HP cables in today that is a more traditional 22awg 4 wire from FogCityAudio vs the Kimber AXIOS 16 wire that I had on the LCD-4s and my S17 dropped 6 degrees down to 50 just from the cable swap, I never turned it off and it only took 30 seconds to swap and its staying 6 degrees cooler....less copper going to load equals cooler? Now to turn the fan off.

 

[AuneAudio]

Now, that is interesting!



I have the 2023.10.19 V5.3
I don't have the volume problem....or at least this is not much an issue for me.
But yes I have the heat issue....
@huyrua811 , you don't use any fan or specific manipulation to keep the amp cool?

I assume the firmware requires some factory or sellers update as there are no USB ports for this....
Really thinking more and more to send back my device.

@AuneAudio we would really like some comments on this for customers having old firmware like mine and what is best to do.
I suppose I can raise a case directly to Aune's support...

Hi, please refer to the replies below

Thanks everybody for all the feedback and support. We are so glad and thankful that you like the sound of the S17 Pro which we made with our heart


To reply to the issues you may be concerned about:


1. The volume control of the S17 Pro is composed of an R2R chip and has 64 steps. The S17 Pro is mainly designed for large headphones. When we received user advice on volume, we took it seriously and have optimized the volume curve.The units now all use the new volume curve. If you are an earlier buyer and if it bothers you, please contact us via Email sales@auneaudio.com for a volume upgrade.


2. The S17 Pro is pure Class-A. Both 50mA mode and 100mA mode are class-A. There’s no Class-AB.




3. The 100mA mode of the S17 Pro is like the GT mode in a car, where the maximum throttle is engaged, and the car's continuous extreme mode also leads to significant power consumption. In 100mA mode, there’s 0.2A per channel, even without headphones connected. The temperature rises noticeably faster compared to 50mA mode. High ambient temperatures and low impedance headphones can cause even faster temperature increases. Setting the jump to 50mA at 69 degrees is to ensure the stability of the device, similar to the restriction of maximum engine speed in a car. As long as the temperature is below 69℃, you can enable the 100mA mode again.


4. Any true Class A amplifier will have thermal noise due to the continuous presence of 100mA static current. The S17 Pro is already a well designed one, with a noise floor of only 4μv which is extremely low. And, as the S17 Pro is just an amplifier, if the front-end equipment has a noise floor, it will cause the S17 Pro to exhibit noise as well. If you are experiencing severe issues, please check your front-end audio source.


Hope the information helps.


Thanks for all your support. May music and joy always be with you

Hi, firmwares can only optimize volume and cannot modify current.



As the S17 Pro is a pure class A headphone amplifier, if a cable is too long and lacks sufficient internal insulation, it may increase the overall load and potentially generate more heat. (High ambient temperatures and low impedance headphones can cause temperature increases too.)

The temperature sensor of the S17 Pro is fixed on the heat sink of the transistor, so it measures the temperature of the output transistor. The screen displays the real-time temperature of the hottest core component.

The picture below shows the temperatures of the chassis when the S17 Pro displays 60 ℃.



Actually, some home routers' internal core components can reach 70 ℃ too. We set the jump to 50mA at 69 ℃ that keeps the temperature of the core components below 69 ℃. In fact, it is safe for the core output transistors to operate below 80 ℃.

However, if you encounter any abnormal situation or excessively high temperatures, it may be a defectiveness issue. Please contact your distributor, and we will ensure your satisfaction

Below is for those who bought aune products from unofficial channels:

Hi, thanks for your feedback. According to your description, if your device reaches 69℃ after 45 min of power up and can only work for 15 min in 100mA mode, there's definitely a problem.

The seller is not our authorized distributor. We don't know who that is. And as you already saw, we mentioned not to buy from Aliexpress:
"Please purchase aune products from our authorized distributors (http://www.auneaudio.com/p/Where_to_Buy.html) and our official Amazon (amazon.com/s?me=A2AP0JEHTRG6EO) where the aftersales service is guaranteed. Aliexpress is NOT recommended as the quality and aftersales service are not guaranteed."

Our authorized distributors pay customs duties, shipping, and other related costs when purchasing products from us to sell in their regions. If one doesn't buy the product through official channels and there's a problem with the unit, even if we as the manufacturer would like to assist him in contacting local distributors for aftersales support, it might be difficult for them to accept products that are not bought from them.

Therefore, products purchased through unofficial channels such as AliExpress have difficulties in obtaining aftersales support. If the seller is unable to provide aftersales service, returning the product to us in China would incur high shipping costs.

That is why we strongly recommend purchasing from authorized distributors or our official Amazon.

In your case, we suggest you to contact the seller for a return.
If the communication doesn't go well, you can directly contact us sales@auneaudio.com

 

[Erick Muller]

Hi everyone,

Nice to see a very active forum trying to work out this nice amp.
Again, it sounds great and I feel the 100ma does help the sound toward my preference...hence the idea to keep it working this way.



@SmartCheetah I just got my unit last week!
But who know how long was it in the stock of the reseller...
I do have a serial like S172405XX...for what it is worth.

I am still wondering if I should:
1 Just deal with it and use the excellent feedback from @Erick Muller to get the right hardware to keep the temp low
2 Give a shot and exchange with another model and just hope it will have improved status
3 return this amp and add a bit more to get an AudioGD Master 19...
Or 4 Open a case with Aune? Did someone tried this already for this issue?
though I have a hunch they may say this is as per normal operation....


Thanks for this @Erick Muller ! That are some great pointers to get the right stuff.
I got the idea and that looks easy enough. I guess the fans you are pointing too, when in lower speed, are pretty silent so, that sounds like a good compromise.

I will keep thinking.
Since I have bought the amp online in Europe, I have still a bit less than two weeks to return it if not satisfied.

Cheers everyone for taking the time to get back to me and wishing you all a good day.

Great, hope this amp it's not to cumbersome for you in it's "requirements", because the sound it produces imho it's worth it.