[Aaron Friedman]

I have been using Aune S17 pro for 1 month. Sounds is good, rich and warm. However, one of the biggest issues I have is "HEATING". This S17 unit is SUPER HOT. My room temp is 20C degree, S17 starts making a good sound when it is warmed up about 50C degree. From 50c to 68c (Maximum) temp shifting speed, it only takes 15mins, Getting hot really fast and temp ramping up really fast. Basically, Aunet S17 pro w/ 100MA mode (Class A) works for ONLY 15 mins, then mode automatically changes back to 50MA mode for over-heat safety.

Still disputing with the seller to get retun approval and money back, seller denied. Really frustrating and disappointed.
In my opinion, do not buy S17 Pro because many other users are experiencing the same heating issue.

Sound like H26 will be a good replacement of S17 Pro!! Good job Gustard !! Great timing !!
Looking forward to see more review of H26.

Thanks for the info. Unfortunately, I have already paid for the Aune s17 pro and it has already shipped. Did you use Tungsten headphones when it overheated? None of the reviewers seemed to have had the overheating issue. By the way the Gustard H26 is class AB on high gain with high impedance headphones, NOT class A. My understanding is that Aune s17 pro is always in class A. I know 1 reviewer thought that the lower 50 setting was class AB. However, my understanding is that it is class A too. Class AB would not be at any level since when not in use it basically shuts down. To me it seems that there are two bias settings within class A. That is why I ordered the Aune S17 Pro too. I find that there is a significant difference between any level bias of class A and Class AB.

 

[Aaron Friedman]

I have a Gustard R26 Dac, and was planning to buy the Gustard P26 preamplifier. Now, with the release of H26, I am considering if I should buy this one instead. But in this case, I am basically looking for a stereo preamp, not a headphone amplifier.

Here are some questions regarding the H26 I have asked both Gustard, and Shenzenaudio. No response, at least till when I posted this:
- Is it possible to change the input and output gains on the H26 between 0dB and +6dB, like on the P26?- (the description does say 2 levels of gain, whatever that means..)
- Could I swap the LME49720 Op-amps to Sparkos Labs SS2590? It is definitely possible to do this on the P26. Not clear if there is enough space to do this on the H26, because the picture of the H26 shows capacitors mounted very close to the Op-amps, and the Sparkos OpAmps are big and need space (1.1 x 1.1 inch, or 2.8 x 2.8 cm)
- In pure Preamp mode, what are the advantages of the H26 compared to the P26 Preamplifier, besides the dual toroidal transformers?
- Is the H26 really a good match for the R26 DAC? I am asking because for XLR input, the H26 claims to have input impedance of only 8K Ohm, compared to 47K Ohm for the P26 preamplifier. Does this not seem like a bit low for a pre-amp? Most pre-amps have much higher input impedance. Like, the Denafrips Hestia is 60K Ohms..

Great questions indeed. I ordered the H26 not to use as a preamp but as a headphone amp only. I do know that the H26 was made for the A26 and R26 primarily to use as a head amp. The preamp function seems to me to be a secondary compromised functional option. It will be interesting to see what they come back with. Please let us know.

 

[Aaron Friedman]

I have been using Aune S17 pro for 1 month. Sounds is good, rich and warm. However, one of the biggest issues I have is "HEATING". This S17 unit is SUPER HOT. My room temp is 20C degree, S17 starts making a good sound when it is warmed up about 50C degree. From 50c to 68c (Maximum) temp shifting speed, it only takes 15mins, Getting hot really fast and temp ramping up really fast. Basically, Aunet S17 pro w/ 100MA mode (Class A) works for ONLY 15 mins, then mode automatically changes back to 50MA mode for over-heat safety.

Still disputing with the seller to get retun approval and money back, seller denied. Really frustrating and disappointed.
In my opinion, do not buy S17 Pro because many other users are experiencing the same heating issue.

Sound like H26 will be a good replacement of S17 Pro!! Good job Gustard !! Great timing !!
Looking forward to see more review of H26.

I just checked online and it confirmed my suspicion on the Aune S17 Pro. The 50ma setting IS class A. The difference between 50ma and 100ma is simply the bias of the current. 100ma will be maximum high current and 50ma is normal current. BOTH are class A. Higher current does sound better but Normal current in class A will still sound better than class AB.

 

[moonbst1]

I just checked online and it confirmed my suspicion on the Aune S17 Pro. The 50ma setting IS class A. The difference between 50ma and 100ma is simply the bias of the current. 100ma will be maximum high current and 50ma is normal current. BOTH are class A. Higher current does sound better but Normal current in class A will still sound better than class AB.

Thank you for the verification of this. Yes, I can feel the difference between 100ma vs. 50ma even thought both mode runs class A. Heating issue happed regardless of ohms or type of headphones. Heat reachs the max temp quilckly even without heaphone with volume "0". Tried height riser (spike), it didn't help. Now I am using the laptop cooling fan under the unit as a temporary solutions. It stays at 58c with cooling fan.

The sound of S17? It is good. VERY Good (with 100ma mode).
Really wondering what sound H26 makes at that price range. Should be better than S17 pro.

 

[Aaron Friedman]

Thank you for the verification of this. Yes, I can feel the difference between 100ma vs. 50ma even thought both mode runs class A. Heating issue happed regardless of ohms or type of headphones. Heat reachs the max temp quilckly even without heaphone with volume "0". Tried height riser (spike), it didn't help. Now I am using the laptop cooling fan under the unit as a temporary solutions. It stays at 58c with cooling fan.

The sound of S17? It is good. VERY Good (with 100ma mode).
Really wondering what sound H26 makes at that price range. Should be better than S17 pro.

Well, I ordered and paid for both the Aune s17 and Gustard H26 Head amps. They should be here next week. I also ordered the Gustard A26 DAC. Note that the A26 Dac is ALWAYS class A. The H26 head amp is NOT class A in high with high impedance headphones. the Gustard H26 At some point goes to Class AB mode. My guess is that the Gustard is technically the better head Amp. However, that does not mean it will have a better soundstage or even sound better. I believe it is likely the Aune will beat it. That is because Aune being a much smaller company takes more chances and is willing to push the limits of the class A high current design.

 

[Aaron Friedman]

Thank you for the verification of this. Yes, I can feel the difference between 100ma vs. 50ma even thought both mode runs class A. Heating issue happed regardless of ohms or type of headphones. Heat reachs the max temp quilckly even without heaphone with volume "0". Tried height riser (spike), it didn't help. Now I am using the laptop cooling fan under the unit as a temporary solutions. It stays at 58c with cooling fan.

The sound of S17? It is good. VERY Good (with 100ma mode).
Really wondering what sound H26 makes at that price range. Should be better than S17 pro.

You may want to look into laptop cooling solutions. There are cooling platforms for laptops that may be a good long term solution.

 

[muths66]

Well, I ordered and paid for both the Aune s17 and Gustard H26 Head amps. They should be here next week. I also ordered the Gustard A26 DAC. Note that the A26 Dac is ALWAYS class A. The H26 head amp is NOT class A in high with high impedance headphones. the Gustard H26 At some point goes to Class AB mode. My guess is that the Gustard is technically the better head Amp. However, that does not mean it will have a better soundstage or even sound better. I believe it is likely the Aune will beat it. That is because Aune being a much smaller company takes more chances and is willing to push the limits of the class A high current design.

So high impendence is not class a??

 

[Aaron Friedman]

So high impendence is not class a??

Not necessarily. On the Gustard H26 if the setting is high and you are pushing it to higher volume TOO then it is Class AB.

 

[muths66]

Not necessarily. On the Gustard H26 if the setting is high and you are pushing it to higher volume TOO then it is Class AB.

Oic. Gustard didn't say high impendence is class ab maybe hugh impedance power is consider low. But well I overall happy with it.

 

[Aaron Friedman]

Oic. Gustard didn't say high impendence is class ab maybe hugh impedance power is consider low. But well I overall happy with it.

It controls heat by changing to Class AB at some higher threshold. My guess is that with 98% of the Headphones out there you will remain in class A.

 

[MrHeadphone86]

Thanks everyone for your input so far, and I'm looking forward to more of your opinions once more people start receiving their devices. I've been following this thread since its inception. I too am very interested in how the Aune S17 Pro and Gustard H26 fair - the Class A competition. I would also be very interested in how both compare to the Schiit Mjolnir 3 which is a fully Class A (always), balanced headamp. I'm looking for a new amp for my Sennheiser HD 800S (300 Ohm) and am still considering all of these as well as the Woo Audio WA6 SE which is a Class A S.E.T. (Single Ended Triode) tube amplifier. The Woo is the most expensive, however I'm looking for my best bang for buck out there.

 

[Roberto1969]

Hi All! I've had the Aune S17 in test- sound is good- but: This thing in my honest opinion shouldn't be sold in this condition. It also doesn't work with the Hifiman HE1000 V2 Stealth- connecting this one to S17 causes temp to exceed 68 degrees very quickly and forcing the system to fall back into 50mA mode frequently. In addition it produces hiss with some upgrade cables. This amp is unstable at the outputs! In addition it reacts to for example Topping or Loxjie remotes causing vol of the S17 to step up or down with every pressed button- never saw something like this. The volume control is a joke! you have about 20 steps- way too less and a frightening jump from level 55 to 56- cathastrophe! Step 01 is far too loud. Further there are some other minor faults- this thing is full of bugs and partly misconstructed- It has potential for the idea- but in this condition the device is badly in need for a revision! I sent mine back and will wait for mk2 version. Greetingz, Robert

 

[moonbst1]

.

 

[moonbst1]

Hi All! I've had the Aune S17 in test- sound is good- but: This thing in my honest opinion shouldn't be sold in this condition. It also doesn't work with the Hifiman HE1000 V2 Stealth- connecting this one to S17 causes temp to exceed 68 degrees very quickly and forcing the system to fall back into 50mA mode frequently. In addition it produces hiss with some upgrade cables. This amp is unstable at the outputs! In addition it reacts to for example Topping or Loxjie remotes causing vol of the S17 to step up or down with every pressed button- never saw something like this. The volume control is a joke! you have about 20 steps- way too less and a frightening jump from level 55 to 56- cathastrophe! Step 01 is far too loud. Further there are some other minor faults- this thing is full of bugs and partly misconstructed- It has potential for the idea- but in this condition the device is badly in need for a revision! I sent mine back and will wait for mk2 version. Greetingz, Robert

One more user here with a heating problem. Good thing you can retun this. Mine ordered from AliExpress. Bad luck, purchased from horrible seller.
If anyone consider to order it from Aliexpress, "All buyers worldwide, beware of the seller below. Despite clear heating issues and provided test result with pictures and videos, this seller has refused return & refund."

AliExpress seller: AKHiFi Audio Store

 

[Revan83]

Well, I don't think heating is a problem. It's just normal working temp for S17 Pro)) The problem is that the device changes mode to 50 mA when it turns hot. So you must use an external fan to cool it down)) Luckly I can't hear any difference between 50 mA and 100 mA with my Focal Radiance, but I still started to think about USB fan to put on the S17 Pro. Something like that:

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