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Why do USB cables make such a difference?
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Oct 21, 2017 at 3:03 PM Post #481 of 1,606
^ Couldn't we also say the that noise is not actively filtered out but - instead - gets filtered out? This is because in the digital world neither the sender nor the receiver can tell the difference between a noisy 1 (or 0) and a clean one.
 
Oct 21, 2017 at 3:13 PM Post #482 of 1,606
Maybe better than "filtered" is to say it is simply ignored. Noise can be mixed with the signal, but the receiver does not pay any attention to it. It does not know how.
The only time noise would play a part is if it is so strong that the receiver can no longer discriminate the 0 and 1 transitions.
 
Oct 21, 2017 at 6:21 PM Post #483 of 1,606
mandrake50 said:
Maybe better than "filtered" is to say it is simply ignored. Noise can be mixed with the signal, but the receiver does not pay any attention to it. It does not know how.
The only time noise would play a part is if it is so strong that the receiver can no longer discriminate the 0 and 1 transitions.
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That was what gregorio wrote. The exception, yes it's possible, but in real use such noise never happens. No cable is gonna save anyone if there is such an overload of noise that the receiver cannot differentiate.
 
Oct 31, 2017 at 11:21 AM Post #486 of 1,606
Clive101 said:
http://madscientist-audio.com/husb.html
http://www.madscientist-audio.com/magictubes.html
Since the thread has stalled, thought I would add these links.
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Haha I've started to read the first link, but that's just too much for me :D

"The Heretical-USB uses a seperately screened pair that is capable of 10x the USB 2.0 data rate (5Gbits/sec). It also uses some tuning to adjust the characteristics of the cable - it's this tuning that gives 90% of the benefit of this cable."

Good old "more is better" :)

I stopped just after this gem:

"A strange thing happened during late testing of the Heretical USB - it became apparent that the 2 meter length sounded better than other lengths. This is not magic; it's due to the capacitance of the cable. 3 meters sounds better than 1 meter but not as good as 2 meters. So it was decided to make 2 meters the minimum length."

What really?????? Are they building FM radio antennas or USB cables? base price is 200$ :D :D there's an email address at the end I'm tempted to just flame them, but they probably already know their product is dog poop.
 
Oct 31, 2017 at 12:35 PM Post #490 of 1,606
Looks like someone putting reese's peanut butter cups all over their stereo system.
 
Oct 31, 2017 at 2:42 PM Post #491 of 1,606
Leporello said:
^ Couldn't we also say the that noise is not actively filtered out but - instead - gets filtered out? This is because in the digital world neither the sender nor the receiver can tell the difference between a noisy 1 (or 0) and a clean one.
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The receiver that extracts the digital data doesn't care (up to a point). Question is what happens to that noise with respect to the rest of the DAC. If allowed to bleed into the DAC reference, clock or analog output, it would show up there.

Fortunately vast majority of DACs -- even the ultra cheap ones -- are immune to this to great extent. And certainly below threshold of audibility.

There are exceptions such as the horribly designed Schiit Modi where if you cough next door, its output changes. :) Using that and Sonore MicroRendu I did a bunch of measurements of USB cables: Here is an example outcome, comparing the TotalDAC d1 "audiophile" USB cable to generic but long one:

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But if you make the generic cable short (yellow), it handily beats the TotalDAC cable (red):
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Switching the DAC to Behringer we see that even the long cable does the same thing as TotalDAC:
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I did bunch more tests of USB cables including "stub" rigid connectors from likes of Uptone:

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Here we see that with sensitive DACs, shorter USB cables is better. But again with half decent DACs, that doesn't matter either:

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I let you read the article for the rest. Bottom line, if you worry about USB cables, just keep their lengths short. Better yet, get a DAC that is insensitive to such things which per above, includes vast majority of DACs.
 
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Oct 31, 2017 at 4:05 PM Post #493 of 1,606
Amirm, does any of that cause audible distortion? It looks to me like every one of those would perform the same for all intents and purposes.
 
Oct 31, 2017 at 8:52 PM Post #494 of 1,606
bigshot said:
Amirm, does any of that cause audible distortion? It looks to me like every one of those would perform the same for all intents and purposes.
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Definitely not if you put the Schiit aside. Even on the Schit it may be hard or impossible to tell. Then again, there is so much schiit going on there, it is hard to find the music within. :)

My reason for posting the data was to show that we can measure it and effects can be there. They bother the eye but the ear is just fine....
 
Nov 1, 2017 at 11:57 AM Post #495 of 1,606
Perhaps I'm reading it wrong. The highest spike in any of those charts appears to be -126dB. I can't imaging that being even close to audible.
 
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