Aune S17 pro

[sendler2112]

"
The class of operation is determined by the biasing of the amplifier stages, mainly the output stage. In AB operation, the output transistors operate in class 'A' mode at low signal levels and then gradually go into class 'B' mode after the transistors reach the more linear portion of their curves.
You can operate an AB amplifier up to 10 watts in 'A' mode but it may require large heatsinks on the output (and perhaps driver) devices and possibly heftier transistors."
https://www.diyaudio.com/community/threads/class-a-to-class-ab-switch.196212/

"
ALL audiophile amps have a slight bias to class A to stop crossover distortion.
but so called all class A amps typically really are just highly biased to class A, but still do switch to AB at high output.

So to answer the op question: ALL modern production solid state amps are biased to Class A to some small (or large) degree.
A very few amplifiers are pure class A"
https://www.audiocircle.com/index.p...L audiophile amps have a,to AB at high output.

 

[Musiccc]

A thought and questions for the knowledgeable members.
If I am not using a hard-to-drive headphones, then I might not need the full power of 100mA current (all the time)?
Using 50mA mode will also reduce HEAT and power consumption?
I read that some people actually preferer the sound of 50mA over the 100mA with their setups.

 

[Musiccc]

And I`m still waiting for my S17 ordered from Hifigo on the 22th November.
Black/220V is rare they say :/

Wow, even Hifigo is short on inventory for this item.

 

[Hooster]

A thought and questions for the knowledgeable members.
If I am not using a hard-to-drive headphones, then I might not need the full power of 100mA current (all the time)?
Using 50mA mode will also reduce HEAT and power consumption?
I read that some people actually preferer the sound of 50mA over the 100mA with their setups.

The bias, 100mA or 50mA has nothing to do with how much power is available to drive headphones. Both should have the same power. Using 50ma will reduce heat and power consumption since it is more efficient than the full class A of 100mA. Whether you prefer the 100mA sound or the 50mA sound is a matter of personal taste.

I am not sure if this amplifier can be recommended to people who don't understand class A and the inherent pros and cons. This might help:

https://www.passlabs.com/technical_article/single-ended-class-a/

"High idle current, or bias, is very desirable as a means of maximizing linearity, and gives an effect which is not only easily measured, but easily demonstrated: Take a Class A or other high bias amplifier and compare the sound with full bias and with bias reduced. (Bias adjustment is easily accomplished, as virtually every amplifier has a bias adjustment pot, but it should be done very carefully). As an experiment it has the virtue of only changing the bias and the expectations of the experimenter.

As the bias is reduced the perception of stage depth and ambiance will generally decrease. This perception of depth is influenced by the raw quantity of bias current.

If you continue to increase the bias current far beyond the operating point, it appears that improvements are made with bias currents which are much greater than the signal level. Typically the levels involved in most critical listening are only a few watts, but an amplifier biased for ten times that amount will generally sound better than one biased for the few watts.

For this reason, designs which operate in what has been referred to as “pure” Class A are preferred because their bias currents are much larger than the signal most of the time. As mentioned, preamp gain stages and the front ends of power amplifiers are routinely single-ended “pure” Class A, and because the signal levels are at small fractions of a watt, the efficiency of the circuit is not important."

https://www.passlabs.com/technical_article/leaving-class-a/

"The benefits of high bias current extend beyond simple harmonic distortion measurements – you also get a reduction of intermodulation distortion (arguably more important), and a lower, more consistent output impedance. As a corollary benefit, the heavy hardware required to support Class A operation will show better thermal stability and will deliver better performance into difficult loads.

So what’s the down-side of high bias operation? In two words: Low Efficiency."

 

[Marlowe]

I am not sure if this amplifier can be recommended to people who don't understand class A and the inherent pros and cons.

Which, of course, you do. Sheesh. Puts out lots of heat is rocket science, no doubt.

 

[Musiccc]

@Hooster

Thanks for taking the time to write this educational info. Very helpful.

 

[Hooster]

Sorry for the off topic but if you want to learn and have some fun in the process you could build something like a class A power amplifier based on the FirstWatt F7 design. I have one and I can confirm it sounds delightful.

https://www.aliexpress.com/i/1005004601467688.html

 

[kopczas]

Wow, even Hifigo is short on inventory for this item.

So I`m not the only one waiting for new gear?

 

[sendler2112]

The Amazon Aune USA store is showing in stock with an arrival date to me of Jan, 3 and the Aune rep told me a couple weeks ago that they sent 16 units with the updated volume control here on Nov, 30.

 

[Simon Patten]

Well that's interesting; Aune posted here a week or two ago offering an update to fix the volume issue and I wanted to send someone the link to the message but I checked the thread back to November 23rd and there's no sign of it now. I don't suppose anyone has a screen cap of it?

I tried contacting the email address they gave and dealt with someone there but they were extremely unhelpful so I want to try another way.

 

[bogi]

Aune posted here a week or two ago offering an update to fix the volume issue

Wasn't that @labeelen in this post?
https://www.head-fi.org/threads/aune-s17-pro.970060/post-17854426

Austria/Germany distributor is servicing their customers, not the whole world.

Aune posted info 2 days ago that S17Pro is Class A.

 

[labeelen]

Well that's interesting; Aune posted here a week or two ago offering an update to fix the volume issue and I wanted to send someone the link to the message but I checked the thread back to November 23rd and there's no sign of it now. I don't suppose anyone has a screen cap of it?

I tried contacting the email address they gave and dealt with someone there but they were extremely unhelpful so I want to try another way.

I also remember the post you are referring to, it was a short message from Aune ww sales that mentioned the service and a contact e-mail but I cannot find the post anymore.
Sales@AuneAudio.com would be a good starting point.

 

[dawidhifi]

Today I am a happy man, very impressed…quick thoughts, full bodied and spacious…easily an improvement over the already great headphone amp on the S9c which seems thinner and sibilant at times in comparison…is it worth paying another 700 usd for?? That’s subjective, but i certainly don’t see me using the amp on the S9c any longer, and i actually thought i would…fantastic job Aune!!!

Your setup looks fantastic! I have the same combo S9c +S17. Can I ask what rack are you using for stacking them?

 

[Simon Patten]

Wasn't that @labeelen in this post?
https://www.head-fi.org/threads/aune-s17-pro.970060/post-17854426

Austria/Germany distributor is servicing their customers, not the whole world.

No, it was a first post from username 'Aune' IIRC so I was a little suspicious but it said to contact sales@auneaudio.com, I did, and they were aware of it but maybe someone posted it unofficially or something. Anyway, the end result was that I was told to return it to the dealer it was purchased from to get the update (what you're saying), which is impractical in my circumstance. I would have thought this was a warranty issue and any dealer should be able to apply the update but apparently not, I contacted my local dealer and got the same answer.

I also remember the post you are referring to, it was a short message from Aune ww sales that mentioned the service and a contact e-mail but I cannot find the post anymore.

No, it's gone, but thanks for confirming it, if I hadn't referred to it in an earlier post I'd have thought I'd dreamt it!

 

[Simon Patten]

My S17 Pro arrived today (thank you Motberg) and I am sitting here with an enourmous grin on my face as I listen to some favourite tracks. The sound quality of this amplifier is outrageous!

I have it propped up an inch above the worktop and I've had it on for 4 hours at around 54 volume, 100mA and high gain and it's still only at 58 degrees so perhaps I'm lucky in that respect. Less so with the volume issue (which I was well aware of), no-go on the update so I'll have to live with that but with sound like this, it won't be a hardship. I can understand people using it as a preamp having problems though.

I like that you can fry eggs on it when you get hungry, nice feature. Maybe I'll move it under the desk to keep my feet warm.

I echo all the praise this device gets for its sound quality, it sounds bloody lovely. It has its faults but I am delighted with it.