Why do different USB ports sound different?

[Purité Audio]

It is the output from the dac which is important.
Keith

 

[antcollinet]

Interference in the form of noise,

Can you hear any noise? Say during silence between tracks with the volume up? If you can is it different between the USB ports?

If not, then noise is not the issue. Noise presents as noise - not as different sound quality (except where the audible noise detracts from the sound)

 

[antcollinet]

So, no explanation, great... This is especially interesting because in this test USB cables were not used for power, they were used for data transfer only. Doesn't make sense.

It is noise only (not harmonics). Most likely a ground noise issue (even when not used for power, the ground is still connected), and if so different cable impedance in the ground connection could result in a difference.

Bear in mind this measured difference is way below the level of audibility.

 

[doalt]

And some here claim that there can be no difference between different USB ports. Here is proof that there is a difference! With measurements. https://archimago.blogspot.com/2018/05/measurements-computer-usb-5v-power.html#more

Since we're talking about measurements, as the "Thoughts and Conclusions" section of this webpage mentioned, how these noise levels affect DAC output hasn't been measured.

That said, ground loop is a common topic for USB DACs. Like this thread:

Ground loops

Hi everyone, I'm planning out my first "proper" desktop system, i.e. separate USB DAC and amp (of presumably good quality), and something I keep seeing mentioned is ground loops, or ground noise. I don't think I have any of this going on in any of my very pedestrian equipment at the moment so...

www.audiosciencereview.com

 

[audio_tony]

And some here claim that there can be no difference between different USB ports. Here is proof that there is a difference! With measurements. https://archimago.blogspot.com/2018/05/measurements-computer-usb-5v-power.html#more

Those tests lack any real information.

Some of the traces shown look like common mode noise which is common when trying to carry out such tests - and meaningless because of the interaction between the equipment doing the measuring and the device under test.

The author fails to provide any detailed information about his test methods. For example, was his oscilloscope connected to one laptop whilst testing another, or did he run the oscillosope software on the device under test?

The author of that article is seemingly also a huge Burson Audio fan. I think that tells you all you need to know.

Finally, that is not "proof there is a difference" not only because of my comments above, but also because the author failed to demonstrate any differences to DAC output (it would seem he didn't even test with a DAC).

Here is some conclusive testing. https://gtkc.net/usb-noise-measurements

In these tests I demonstrate that ground loops are the single biggest issue with USB DACs.

 

[Crosstalk]

it is even possible to 'fake' such proof (measurements).

everyone is free to fake measurements.

 

[solderdude]

or botch them for whatever reason.

 

[Audiofire]

everyone is free to fake measurements.

People are free to do a lot of counter-productive things, which are not worth doing.

 

[LongKick64]

everyone is free to fake measurements.

In short, everyone around is lying and it is impossible to prove anything to anyone.

 

[Purité Audio]

Not everyone, ‘boutique’ cable manufacturers certainly.
Keith

 

[unpluggged]

In short, everyone around is lying and it is impossible to prove anything to anyone.

What exactly are you striving to prove here? If you think different USB ports sound differently, then it's your right and your experience, good for you. Others may disagree with you, so don't waste your time.

 

[Doodski]

In short, everyone around is lying and it is impossible to prove anything to anyone.

Because the theory of the operation of digital circuitry denotes that USB ports do not sound different when operating properly.

 

[somebodyelse]

And some here claim that there can be no difference between different USB ports. Here is proof that there is a difference! With measurements. https://archimago.blogspot.com/2018/05/measurements-computer-usb-5v-power.html#more

True, but missing the point entirely - this variation in power line noise is well known and expected. A competently designed USB DAC has sufficient internal regulation to deal with this, so its output won't be affected by this variation in noise. Refer back to post #55 for links to Archimago's test demonstrating this for a well designed DAC, and for the Modi 2 test where it wasn't done properly.

 

[LongKick64]

What exactly are you striving to prove here? If you think different USB ports sound differently, then it's your right and your experience, good for you. Others may disagree with you, so don't waste your time.

Ok.

 

[unpluggged]

True, but missing the point entirely - this variation in power line noise is well known and expected. A competently designed USB DAC has sufficient internal regulation to deal with this, so its output won't be affected by this variation in noise. Refer back to post #55 for links to Archimago's test demonstrating this for a well designed DAC, and for the Modi 2 test where it wasn't done properly.

I don't think we need to feed this troll and explain them the obvious basics a thousandth time over. It's obvious they are just fooling around here out of boredom. Let's ignore them. All their contribution here is making outrageous claims and trying to get attention.

 

[somebodyelse]

Because the theory of the operation of digital circuitry denotes that USB ports do not sound different when operating properly.

'when operating properly' has a number of assumptions built in. I covered some in post #55 - feel free to add any I missed. Back in post #13 OP's description of noise seems like a ground noise issue which may genuinely be different between ports. Insufficient 5V line regulation/filtering is another possibility, although less common.

 

[LongKick64]

Thanks to everyone who helped clarify the situation, I will probably order Topping HS02 and check if anything changes.

 

[LongKick64]

By the way, if I connect headphones, especially very sensitive, in-ear headphones, for example, Sennheiser IE 4 to the 3.5 port of my computer, I clearly hear noise in the left earphone. This is VERY noticeable noise. Compared to it, the noise that I hear through the USB port is barely noticeable.

 

[Sokel]

These kind of stuff (USB noise) is far from solved,in fact it's all over and one of the most common threads around forums.
Mixing class I and class II devices is the obvious reason.

Unless galvanic isolation becomes the standard (as Eversolo does with its new streamer) this will be an ongoing issue,no matter how nicely a DAC measures in isolation or how well is made.

 

[xaviescacs]

The one that I like the sound from more?

Definitely! What other choice you have?