Aune S17 pro

[Vap221]

It's very sad. Of course, none of the cable manufacturers indicates their inductance and capacitance. In addition, hybrid headphones are a complex reactive load with a very uneven impedance. When there is no self-excitation, no softening of the sound on the HF occurs. Aune easily (not explicitly) confirmed my conclusions, (see the last paragraphs of Aune's answer) noise and abnormal heating, dependence on the cable. If my conclusions were valuable only to me, but after reading the topic, I was convinced that problematic devices are not uncommon.

I have the ability to measure the capacitance, inductance, impedance, "capacitive resistance" of cables. But 99% of users do not have this option.

 

[Vap221]

Impedance 1khz
L1 150mOhm
L2 140mOhm
R1 140mOhm
R2 131mOhm
Inductance per line
1.35MCG
Capacity between channels
66.3pF
Capacity per channel
L 90pF
R 100pF
Capacitive impedance
1kHz 2.3MOm
10kHz 241K
40kHz 62K

 

[Majuto]

Unfortunately I think it would be an impossible task given how many different cables are on the market, the only way you're going to find about it is to connect to your HP and then the S17 and see if the temps start rising really fast on the amp, then you have a "bad" cable, and this assumes you have a "good" cable to compare it too already paired with the same headphone that doesn't have those issues in combination with this amp.

The other way would be to have all that measuring equipment and 99.99% of people, even in this forum, don't have it.

It has to be said Aune is the only amp I've ever had differences in it's behaviour because of cables. One case happened with Raal Ca-1a when I bought an "upgrade cable" for it and oddly the sound level was about 15-18db under what it should have been. I wondered this in Raal Requisite thread where I guess the best idea was, that the cable producer had calmly made a cable without considering the facts. Raal's resistance is minimal, something like 0,2 ohms. So I returned this good but bad cable. No use with it!

 

[Majuto]

Impedance 1khz
L1 150mOhm
L2 140mOhm
R1 140mOhm
R2 131mOhm
Inductance per line
1.35MCG
Capacity between channels
66.3pF
Capacity per channel
L 90pF
R 100pF
Capacitive impedance
1kHz 2.3MOm
10kHz 241K
40kHz 62K

Could you define the parasitic inductance and capacitance. Which values could be considered as low, medium and high?

 

[Erick Muller]

Impedance 1khz
L1 150mOhm
L2 140mOhm
R1 140mOhm
R2 131mOhm
Inductance per line
1.35MCG
Capacity between channels
66.3pF
Capacity per channel
L 90pF
R 100pF
Capacitive impedance
1kHz 2.3MOm
10kHz 241K
40kHz 62K

In my personal experience, I wouldn't recommend this amp for IEM's, not just because of the gain and how much power output it has, but because there's definitively a background hiss that can be somewhat perceptible on in ears.

 

[Vap221]

Could you define the parasitic inductance and capacitance. Which values could be considered as low, medium and high?

there are no such concepts. inductance, impedance, capacitance, this is exactly what, in combination with headphones and an amplifier, causes the cable to "color the sound". Many cable manufacturers deliberately experiment with these parameters. The cable has NO parasitic parameters.

 

[Vap221]

In my personal experience, I wouldn't recommend this amp for IEM's, not just because of the gain and how much power output it has, but because there's definitively a background hiss that can be somewhat perceptible on in ears.

this is just an example of the parameters of a specific cable.

There are iem headphones with low sensitivity or high impedance. Most iem planars have low sensitivity.

 

[Simon Patten]

This got me interested again so I thought I'd double-check my results with a fresh test.

With nothing plugged into my S17 Pro the temperature is stable at 58-59 degrees.

Using the Null Audio Epsilon cable with my HEKS, it sits happily at 59-60 degrees.

Using the Null Audio Ethos MkV cable with my IE600s, the temperature immediately starts to increase.

It's hard to believe that a decent cable could be doing this so after unplugging the Ethos and letting the S17 cool down to 60 degrees, I disconnected the IE600s from the Ethos and plugged the cable back in with open ends. The temperature immediately started rising until I unplugged it at 63 degrees and let it cool again.

Just for the heck of it, I unplugged the Epsilon cable from the HEKS and plugged it in open ended. It rose to 61 degrees and was stable for 1/2 hour, dropping back to 60 degrees when I plugged the HEKS back in.

It's interesting that two cables from Null Audio give different results so I think I'll email them with this info and ask if they have an explanation. I suspect it will be something to do with capacitance of inductance, Supra cables make a thing about that.

cc @AuneAudio

 

[Vap221]

This got me interested again so I thought I'd double-check my results with a fresh test.

With nothing plugged into my S17 Pro the temperature is stable at 58-59 degrees.

Using the Null Audio Epsilon cable with my HEKS, it sits happily at 59-60 degrees.

Using the Null Audio Ethos MkV cable with my IE600s, the temperature immediately starts to increase.

It's hard to believe that the decent cable could be doing this so after unplugging the Ethos and letting the S17 cool down to 60 degrees, I disconnected the IE600s from the Ethos and plugged the cable back in with open ends. The temperature immediately started rising until I unplugged it at 63 degrees and let it cool again.

Just for the heck of it, I unplugged the Epsilon cable from the HEKS and plugged it in open ended. It rose to 61 degrees and was stable for 1/2 hour.

It's interesting that two cables from Null Audio give different results so I think I'll email them with this info and ask if they have an explanation. I suspect it will be something to do with capacitance of inductance, Supra cables make a thing about that.

cc @AuneAudio

this suggests that with these cables, the amplifier is excited. I can assume that there are also problems with both cables. Under certain conditions, this can be understood by the sound change depending on current and gain, this should not happen with any cables. The cable manufacturer has nothing to do with it. The essence of different cables is that they have different capacitance and inductance.

 

[Simon Patten]

this suggests that with these cables, the amplifier is excited. I can assume that there are also problems with both cables. Under certain conditions, this can be understood by the sound change depending on current and gain, this should not happen with any cables. The cable manufacturer has nothing to do with it. The essence of different cables is that they have different capacitance and inductance.

Indeed. I'll write to Null Audio and post their reply here.

 

[Vap221]

as promised, I am publishing waveforms of the maximum operating modes. The oscilloscope slightly overestimates the effective voltage value. My equivalent load does not allow me to take measurements for longer than 1 second due to overheating at the maximum capacity. Therefore, I do not have time to make a measurement with an accurate AC voltmeter.

 

[AntonNZ]

@Vap221 I put your oscillograph shots into excel, and try to sort it by voltage (any of them) value and it all seems to be relatively linear. the only issue I can see is that frequency changes on the high values(shots 3, 4, 5). But I don't know what is considered to be norm, unfortunately

also puzzling that distortion goes only on thousands of frequencies, like 2K, 3K, 4K, 5K and etc.

 

[AntonNZ]

Did anyone tried openheart cables from aliexpress 16 cores and/or 8 cores?

 

[Vap221]

Did anyone tried openheart cables from aliexpress 16 cores and/or 8 cores?

normal cables. Only I'm afraid because of the dense weaving, they have a high inductance, they will lead to self-excitation of Aune

 

[SmartCheetah]

For me the takeaway and two major questions are:

1. Do you have any heating issues? (might be related with self-excitation = SQ distortions as discussed in this thread)
2. Do you like the sound?

Since it's NO+YES in my case, the measurements and discussions are super interesting, but don't really change my perception of this product. To put it plainly (and sorry if I will sound ignorant ) - why should I or anyone care about the measurements if the listening experience is so good? I also keep in mind that some of the perfect measuring devices on the market turned out not being particularly praised for the actual sound quality, being criticized by some reviewers for sounding neutral, but in a bad way - lifeless, cold or thin.

Did anyone tried openheart cables from aliexpress 16 cores and/or 8 cores?

I used it with an 8-core Openheart and a 16-core one of some other brand from AliExpress. No temperature issues with either.