[Erick Muller]

Addressing your three comments in order:

1. That's not what you originally said...you said "I find that the Mojo 2 works better between 2 and 3 V. Above 3V it starts clipping"
Now you are happily quoting that it clips above 4.3V?
I'm pleased to see you've realised you were incorrect.

2. According to this review by Soundnews, the amp uses Class-A/B for the 50mA mode - but if that isn't the case, I stand corrected.
Again, @AuneAudio can you please clarify whether the S17 Pro uses Class-A/B mode for 50mA?

3. I've never said the TA-22 gives you 100mA/ch. Nor do I care about its operating temperature. What I have said is that is in many cases (judging by this forum), the S17 Pro states it does offer 100mA/ch, but clearly cannot do that consistently, without modifications at the owners' expense.
Nowhere does Aune state that you must use a particular type of headphone cable or a cool room otherwise you can't consistently use the 100mA mode.
As a further example, the Violectric and Burson make amps that can use Class-A mode continuously, without overheating and having to adjust their operating mode. They don't need platforms, feet or fans.

I'm glad that you're happy with the amp and your platform and your fan and I'm glad that you think it is worth the effort. That's great.
Personally I would like an amp that uses Class-A consistently, without me having to make modifications.

I do hope that's all clearer now and I look forward to @AuneAudio clarifying the two questions I asked them.

Burson it's using cooling fans and pretty significant heat sink solutions, specially on their newest amp, the voyager, and also cost thousands of dollars, so I expect them to work without a single hitch or problem at that price point. Also the Violectric HPV222 it's like the closer competitor to the S17 and it's MSRP it's about $1,300 usd, sometimes you can find it cheaper on Drop.com, but still more expensive than the S17 even with the better pricing.

Yep, Aune could had done a lot more things to make this amp better, most of this would have meant increasing the price of this amp significantly, Is this a perfect product?, nope, do you have to do somethings in order to run this amp at 100ma, high gain constantly that are kind of cumbersome and annoying? yes. Is it the end of the world? far from it. Like I've seen plenty of people using fans to help cool Schiit's MJ3 and people are not complaining that much about that amp and also there has been problems with switches, volume pots going bad and now swollen caps that are failing on this amp and even tho this amp is almost twice as expensive as the S17, people just accept it that they have had to send now multiple times there MJ3 for repairs just because of brand's name, which is well deserved, when in comparison I personally have seen a lot less significant issues with the S17 in comparison. It personally annoys me a lot that we're willing to call this amp "bad" when other companies can get away with the same or even worse just because people are really biased in this hobby.

 

[MiguelP]

Burson it's using cooling fans and pretty significant heat sink solutions, specially on their newest amp, the voyager, and also cost thousands of dollars, so I expect them to work without a single hitch or problem at that price point. Also the Violectric HPV222 it's like the closer competitor to the S17 and it's MSRP it's about $1,300 usd, sometimes you can find it cheaper on Drop.com, but still more expensive than the S17 even with the better pricing.

Yep, Aune could had done a lot more things to make this amp better, most of this would have meant increasing the price of this amp significantly, Is this a perfect product?, nope, do you have to do somethings in order to run this amp at 100ma, high gain constantly that are kind of cumbersome and annoying? yes. Is it the end of the world? far from it. Like I've seen plenty of people using fans to help cool Schiit's MJ3 and people are not complaining that much about that amp and also there has been problems with switches, volume pots going bad and now swollen caps that are failing on this amp and even tho this amp is almost twice as expensive as the S17, people just accept it that they have had to send now multiple times there MJ3 for repairs just because of brand's name, which is well deserved, when in comparison I personally have seen a lot less significant issues with the S17 in comparison. It personally annoys me a lot that we're willing to call this amp "bad" when other companies can get away with the same or even worse just because people are really biased in this hobby.

On headphonesty review of the Xduoo TA-22 they say that they've received two faulty units for review!

 

[davehutch]

I'm going to leave everyone to fight over this amongst themselves. I simply said that personally I'm put off by the fact that many people need to have special platforms, cables and fans to run their S17s.
I don't defend any other amps because I haven't chosen one yet. My understanding is that the S17 sounds fantastic for the price

 

[Erick Muller]

Yeah, the sensor measures the hotspot around the heatsink.

The hottest section on the amp is on the underside, if you touch it, it's uncomfortably hot, also when the temps on the amp go to 65 or above, in my unit at least, on the right side of the amp, looking it at the front, on the side the volume pot is, it can also get uncomfortably hot to the touch, so I'm not saying that you can use this amp as a pillow, but on most of the amps surface it's safe to the touch, it's just warm, not scorched you hands kind of hot, and even on it's hottest sections, it's not dangerously hot like for example a tube amp can be if you touch the tubes, so I think this is an incredibly bad faith argument because everyone knows that fully discrete, class-a amps run hot, but tube amps get incredibly hot on their tubes themselves, that's why the TA-22 comes with a special guard so you don't burn yourself accidentally.

 

[AuneAudio]

Addressing your three comments in order:

1. That's not what you originally said...you said "I find that the Mojo 2 works better between 2 and 3 V. Above 3V it starts clipping"
Now you are happily quoting that it clips above 4.3V?
I'm pleased to see you've realised you were incorrect.

2. According to this review by Soundnews, the amp uses Class-A/B for the 50mA mode - but if that isn't the case, I stand corrected.
Again, @AuneAudio can you please clarify whether the S17 Pro uses Class-A/B mode for 50mA?

3. I've never said the TA-22 gives you 100mA/ch. Nor do I care about its operating temperature. What I have said is that is in many cases (judging by this forum), the S17 Pro states it does offer 100mA/ch, but clearly cannot do that consistently, without modifications at the owners' expense.
Nowhere does Aune state that you must use a particular type of headphone cable or a cool room otherwise you can't consistently use the 100mA mode.
As a further example, the Violectric and Burson make amps that can use Class-A mode continuously, without overheating and having to adjust their operating mode. They don't need platforms, feet or fans.

I'm glad that you're happy with the amp and your platform and your fan and I'm glad that you think it is worth the effort. That's great.
Personally I would like an amp that uses Class-A consistently, without me having to make modifications.

I do hope that's all clearer now and I look forward to @AuneAudio clarifying the two questions I asked them.

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

The spec page of the S17 Pro has the input impedance

Input: single-ended 2VRMS/balanced 4VRMS

 

[Coolmoose]

Burson it's using cooling fans and pretty significant heat sink solutions, specially on their newest amp, the voyager, and also cost thousands of dollars, so I expect them to work without a single hitch or problem at that price point. Also the Violectric HPV222 it's like the closer competitor to the S17 and it's MSRP it's about $1,300 usd, sometimes you can find it cheaper on Drop.com, but still more expensive than the S17 even with the better pricing.

Why are you only comparing the S17 to amps that are double its price? What about amps that half its price and work as intended?

do you have to do somethings in order to run this amp at 100ma, high gain constantly that are kind of cumbersome and annoying? yes. Is it the end of the world? far from it.

This is a flawed product then, when I buy a something, no matter the price, it should work as advertised. I don't see anywhere where it says "must use external cooling for full performance."

It personally annoys me a lot that we're willing to call this amp "bad" when other companies can get away with the same or even worse just because people are really biased in this hobby.

So, what your basically saying if another company can get away something like this, its OK for Aune to do the same?

This amp sells for like 300 bucks on the used market in China, I was curious because I have heard good things about it. So I bought it and sold it 3 days later due to all the problems mentioned. Not worth the trouble. YMMV.

 

[Dimitry188]

Why are you only comparing the S17 to amps that are double its price? What about amps that half its price and work as intended?

Because for its price, Aune S17 Pro has no competitors - they sound noticeably simpler and worse.

 

[Coolmoose]

Because for its price, Aune S17 Pro has no competitors - they sound noticeably simpler and worse.

My concern is not with the product’s subjective performance; rather, regardless of whether the manufacturer’s price point is $100 or $10,000, the product should function as designed.
For example the topping A30pro I have has better measurements, is almost as powerful, and only cost 250 dollars. So by your logic, it should be fine if it had problems with volume control or overheating because I subjectively believe that its has no competitor in its price range?

 

[Ichos]

Sandu at Soundnews (as well as Ichos, who said the same) are very good reviewers, but they got this wrong. Aune has already clarified this in this very thread (at least once, though I'm not searching for it) stating flatly that the S17 always operates in Class A mode whether it is in 50mA or 100mA mode.

Update: As you can see a few posts down, Aune now clarifies this point yet again.

This is true and have been corrected in my review from day one when I got the Aune answer.

The S17 Pro is always Class A no matter the bias current.

 

[Erick Muller]

Why are you only comparing the S17 to amps that are double its price? What about amps that half its price and work as intended?

I'm addressing other people in this thread comparing the S17 to other amps that cost several times what this amp cost.

This is a flawed product then, when I buy a something, no matter the price, it should work as advertised. I don't see anywhere where it says "must use external cooling for full performance."

I agree but it doesn't seem to be an issue that affects everyone to the same degree or at all, when I'd to use my cooling fans it's in very limited circumstances and that's after hours and hours of use.

So, what your basically saying if another company can get away something like this, its OK for Aune to do the same?

I never said that in any part of my argument, learn to read please.

This amp sells for like 300 bucks on the used market in China, I was curious because I have heard good things about it. So I bought it and sold it 3 days later due to all the problems mentioned. Not worth the trouble. YMMV.

Irrelevant point.

 

[Pelilin]

Has anyone here manage to compare this with Hifiman Serenade?

Edit: wait.... I think i missread the description of the product. Is this R2r dac amp or just an amplifier?

 

[Erick Muller]

My concern is not with the product’s subjective performance; rather, regardless of whether the manufacturer’s price point is $100 or $10,000, the product should function as designed.
For example the topping A30pro I have has better measurements, is almost as powerful, and only cost 250 dollars. So by your logic, it should be fine if it had problems with volume control or overheating because I subjectively believe that its has no competitor in its price range?

If you're happy with a topping amp or any other product form any other company at any other price point, good for you, this product it's not for you and I'm sorry it was a waste of time and money in your case.

The amp it's not "over heating", please stop repeating misinformation, what happens is that when the amp reaches 69 degrees, it changes back to 50ma mode, that's it, it seems that people think that when this amp reaches 69 degrees it explodes or something, nope, you can still listen to music and it still sound great on 50ma mode for most people. The volume pot problem has already been address and if you're not happy with how the volume works in this amp, you can send back your S17 so it's programmed with a newer firmware that addresses this issue.

 

[MiguelP]

If Aune removed the temperature info from the screen and said nothing about different current bias modes, this amp would be a much bigger success. Has anyone, completely blindfully, ever noticed, by ear, the exact moment when the unit switches back to 50ma? I'm betting that the (honest) answer is no for every single user.

 

[Erick Muller]

If Aune removed the temperature info from the screen and said nothing about different current bias modes, this amp would be a much bigger success. Has anyone, completely blindfully, ever noticed, by ear, the exact moment when the unit switches back to 50ma? I'm betting that the (honest) answer is no for every single user.

Depends on the headphones, but in most cases I will have to admit it would be hard to make out the difference.

 

[Erick Muller]

Has anyone here manage to compare this with Hifiman Serenade?

Edit: wait.... I think i missread the description of the product. Is this R2r dac amp or just an amplifier?

The volume control it's R2R, and this is an amp, a fully discrete, class-A amp.