Aune S17 pro

[sendler2112]

Hopefully Aune releases a successor at some point without all the "quirks" of the S17 pro. Very intrigued by the sound descriptions, but having to even think about the operating temperature seems like a massive flaw in product design. I can just turn my Burson on and never have to worry if running it during the summer will change the sound.

I'm waiting for a version of the S17 that actually uses ALL of its 64 volume steps in hopes that it will sound even better whenever they fix whatever went wrong if it is something to do with a relay or resistor chip rather than just implementing the current firmware workaround patch.

 

[SmartCheetah]

Hopefully Aune releases a successor at some point without all the "quirks" of the S17 pro. Very intrigued by the sound descriptions, but having to even think about the operating temperature seems like a massive flaw in product design.

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.

 

[Dimitry188]

can you describe the difference in sound quality between the 100mA and 50mA modes?

The 100 mA mode is much more interesting in detail. The 50 mA mode sounds more simplified on good headphones.

 

[Thetaburn]

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.

Absolutely, this is a deal breaker for me.
The last thing I want is to purchase an additional product ( fans or heatsink ) to make things work properly.
Other class A amps do not have this issue ( Burson, Schiit Mj3 and etc ).
I want to enjoy the music not monitor temperature.
Aune needs a revision where they have a larger heat sink.

 

[SpiritualAbies2600]

If I might add my 2 cents in... I think the issue here is that not many people make class A products anymore.

I grew up when you had Class A Speaker Amplifiers that weighed a TON with crazy sized heatsinks that could warm up the room.

I believe the issue here is people are not used to Class A topology anymore. Then there is a fact that Aune SHOWS you the temps while other companies simply activate internal step down sockets.

For example, LG C2/G2, Sony X series, Samsung top of the line OLED TVs do the same thing. When there is a very bright full screen image, they start to get to warm AND they turn down the brightness until they are have cooled down. This is called ABL (Automatic Backlight Control). If they didn't do this, the screens would overheat. If you want that perfect contrast ratio, you have to be willing to deal with ABL every once in a while. Otherwise, get LED TVs and deal with local dimming and blooming issues. LOL. The Aune is doing the same thing as these manufacturers when it powers down to 50 ma to allow itself to cool, EXCEPT that it shows you temps while on your TV, you have no idea what temp... you just want the picture.

Toyota, Ford, GM vehicles all do the same thing... If the vehicle starts overheating, they pull timing to reduce engine horsepower until they can cool down. Once cooled down, then they restore the horsepower.

So to me what Aune is doing is not abnormal if you want class A JET topology.

 

[Slackaveli]

yeah you really cant complain about a hot class A amplifier lol.

 

[Currawong]

There's an interesting factor I've observed with products, where if a manufacturer adds a feature, but does an imperfect job of it, they end up worse off than if they hadn't added it at all, because most of the discussion ends up about the imperfection. With the S17, it's all of the two bias modes, screen and temperature measure, which have ended up drawing attention away from discussion of the sound.

In reality, owners of the amp don't really need to worry. Nothing bad is happening if it gets hot enough that if in 100mA mode it reverts automatically to 50mA mode. Component parts are usually rated at 85C or 105C so it is unlikely to get hot enough to damage anything.

 

[Slackaveli]

There's an interesting factor I've observed with products, where if a manufacturer adds a feature, but does an imperfect job of it, they end up worse off than if they hadn't added it at all, because most of the discussion ends up about the imperfection. With the S17, it's all of the two bias modes, screen and temperature measure, which have ended up drawing attention away from discussion of the sound.

In reality, owners of the amp don't really need to worry. Nothing bad is happening if it gets hot enough that if in 100mA mode it reverts automatically to 50mA mode. Component parts are usually rated at 85C or 105C so it is unlikely to get hot enough to damage anything.

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.

 

[MiguelP]

I'm waiting for a version of the S17 that actually uses ALL of its 64 volume steps in hopes that it will sound even better whenever they fix whatever went wrong if it is something to do with a relay or resistor chip.

There's nothing wrong with the new volume implementation and a new firmware for the volume implementation would do

There's an interesting factor I've observed with products, where if a manufacturer adds a feature, but does an imperfect job of it, they end up worse off than if they hadn't added it at all, because most of the discussion ends up about the imperfection. With the S17, it's all of the two bias modes, screen and temperature measure, which have ended up drawing attention away from discussion of the sound.

In reality, owners of the amp don't really need to worry. Nothing bad is happening if it gets hot enough that if in 100mA mode it reverts automatically to 50mA mode. Component parts are usually rated at 85C or 105C so it is unlikely to get hot enough to damage anything.

I agree. The biggest mistake Aune has made is to include the screen. It would be perfect if they opted for switches.

Miguel

 

[Currawong]

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

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

 

[SackATK]

I received my pre-owned black Aune S17 Pro earlier this month. The sound is excellent regardless of the price. I have my unit on five aluminum heatsinks that raise the amp about 2 inches. The temp gets to about 67 in 100MA mode after an hour of listening. My IEMs are Sennheiser IE900s. I don't know if my choice of earphone is contributing to the heat or not. If it reaches 69, I will add more heatsinks to cool it down. I want to avoid adding a fan to the system.

My other amp is the Ferrum Oor powered by a 24V iFi Elite power supply. Although not as good as the Hypsos on the Oor, the IFi Elite gets close enough in performance. The S17 and the Oor both have their advantages and disadvantages. In my system, the S17 had very low listening fatigue and it was more detailed in that I was able to appreciate certain things in the sound I had never appreciated before. But at the same time, certain parts of the music felt veiled compared to my past memory of listening to that music. Now understand I've created some very detailed systems in the past so this isn't really a knock on the S17. It's just my bar has been raised. I also prefer my music to have a little more "attack" than what I was getting with the S17 alone. The Oor has more of that attack nature that I like but is missing that Class A sound like the one found on the S17. My Oor is put on volume bypass mode and I control the volume with a Lumin U1 Mini.

In a past system, I added a Holo Serene preamp in front of my Oor/Hypsos stack and the sound changed for the better. This unleashed the Oor/Hypsos to a higher potential. To this day, the Oor/Hypsos with the Serene is still part of the best system I've ever built. So then I tried the S17 as a preamp to the Oor. The sound was better than the S17 or the Oor alone but it still had more listening fatigue than I would like. The music could get bright at times.

Then I tried the Oor as preamp (still in volume bypass mode) before the S17. Now this is what I wanted all along. This configuration is amazing! All of the benefits of both the Oor and the S17 are put together. There is great synergy in this setup. I'm getting more details, the attack, the energy, the fun. I don't get the listening fatigue. I'm enjoying the sound so much, I find myself not skipping over the "boring" songs.

I should describe the rest of my system: Lumin U1 Mini > Ghent Audio USB > SMSL PO100 DDC > Tubulus Concentus V2 I2S > Musetec MH-DA005 DAC > Zavfino Silver Dart XLR > Ferrum Oor > Zavfino Fusion XLR > Aune S17 Pro > Sennheiser IE900s. For power, I'm off grid and I use a Battery/Inverter system and a Shunyata Typhon T2 power conditioner. Power cables are Zavfino and Shunyata and DC power is from an HDPlex 300W.

 

[Thetaburn]

There's an interesting factor I've observed with products, where if a manufacturer adds a feature, but does an imperfect job of it, they end up worse off than if they hadn't added it at all, because most of the discussion ends up about the imperfection. With the S17, it's all of the two bias modes, screen and temperature measure, which have ended up drawing attention away from discussion of the sound.

In reality, owners of the amp don't really need to worry. Nothing bad is happening if it gets hot enough that if in 100mA mode it reverts automatically to 50mA mode. Component parts are usually rated at 85C or 105C so it is unlikely to get hot enough to damage anything.

Do you know if the Schiit Mjolnir 3 steps down in sound quality if the internals reach over a certain temperature?

 

[AntonNZ]

Question for those who have heat issues:
can you try to tighten three bolts in the bottom as per the picture below and see whether it helps?

HINT: The power supply is on the side with the green cover
As we can see it is a HUGE heat sink that is connected to the bottom plate. However, if it is not tightened properly it could potentially affect the heat dissipation. and that can be a reason why some users can have some issues where others -not
I'm not advising to get inside the unit since Aune didn't confirm whether it will void the warranty or not... but tightening some screws should be fine.

 

[SmartCheetah]

I have my unit on five aluminum heatsinks that raise the amp about 2 inches. The temp gets to about 67 in 100MA mode after an hour of listening. My IEMs are Sennheiser IE900s.

That seems high considering your unit has been elevated and has added heatsinks. After I elevated mine, it won't go past 61 degrees on for the full day in 100mA. With my IEMs it has been below 60.

So it's either that connecting different headphones/cables give wildly different results, or some units heat up more than others. Do you have the newer batch with the improved potentiometer?

 

[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.