[AmpDesigner333]

I’m getting older, wiser, and frankly tired of having to undo the misinformation out there regarding USB Audio.

In this thread, I will explain why the USB cable that connects your source (PC or other) to your DAC shouldn’t matter, as long as it is of reasonable quality and is undamaged.

First, let’s talk about the nature of USB Audio....

Just curious who already knows this: Where is the audio data “clock” coming from?

[AmpDesigner333]

....and not TOO long.

[whopnyc]

Subscribed!...mostly for the comments. 

[mix4fix]

I’m getting older, wiser, and frankly tired of having to undo the misinformation out there regarding USB Audio.

In this thread, I will explain why the USB cable that connects your source (PC or other) to your DAC shouldn’t matter, as long as it is of reasonable quality and is undamaged.

On the same subject: if the USB cable doesn't matter, is a plain-Jane USB cable good enough/not as bad as people say?

[DannyBadorine]

Just curious who already knows this: Where is the audio data “clock” coming from?

Isn't the clock in the digital to analog converter? So therefore it's after the USB cable.

Although I realize that the clock can be separate from the D/A converter, I think it's integral to the conversion process.  But I'm no expert.

[AmpDesigner333]

On the same subject: if the USB cable doesn't matter, is a plain-Jane USB cable good enough/not as bad as people say?

If a “plain jane” cable works, and a super fancy cable works, there will be no difference in sound quality UNLESS the equipment design is faulty.

How can it be “faulty”?  One way is relying on USB power without any conditioning (aka reconstruction) to run the rest of the hardware.  Another is a lack of error detection, and that’s just not going to happen when using a decent USB “receiver” interface chip.

[AmpDesigner333]

Isn't the clock in the digital to analog converter? So therefore it's after the USB cable.

Although I realize that the clock can be separate from the D/A converter, I think it's integral to the conversion process.  But I'm no expert.

The USB interface clocks the data by way of packet requests.  Therefore, any claims of “lower jitter” regarding a fancy USB cable are ludicrous.

[AmpDesigner333]

PLUS, if you’re using a USB-to-SPDIF converter such as the Cherry USB, the data is re-clocked by the DAC, which is the case for any SPDIF connected DAC, such as the Cherry 130dB+ DAC DAC 2.

[whell]

PLUS, if you’re using a USB-to-SPDIF converter such as the Cherry USB, the data is re-clocked by the DAC, which is the case for any SPDIF connected DAC, such as the Cherry 130dB+ DAC DAC 2.

Great thread!

So, if a user has a USB to SPDIF converter feeding a DAC, you're saying the data is re-clocked once by the converter, and then re-clocked by the DAC?  Does sending the data through multiple "re-clockings" (is that a word?  ) have any negative effects on the data?

Never thought that a cable would have any impact on jitter, but I don't mind spending a bit more (not more than $50) for a USB cable that I know is well constructed. 

[AmpDesigner333]

Great thread!

So, if a user has a USB to SPDIF converter feeding a DAC, you're saying the data is re-clocked once by the converter, and then re-clocked by the DAC?  Does sending the data through multiple "re-clockings" (is that a word?  ) have any negative effects on the data?

Never thought that a cable would have any impact on jitter, but I don't mind spending a bit more (not more than $50) for a USB cable that I know is well constructed.

That's a good rule of thumb price wise!

Yes, the data is reclocked twice with USB -> SPDIF -> DAC, but the data itself remains unchanged, thus no difference in the sound!

[mix4fix]

If a “plain jane” cable works, and a super fancy cable works, there will be no difference in sound quality UNLESS the equipment design is faulty.

How can it be “faulty”?  One way is relying on USB power without any conditioning (aka reconstruction) to run the rest of the hardware.  Another is a lack of error detection, and that’s just not going to happen when using a decent USB “receiver” interface chip.

Why do people claim that they hear a difference? Are they looking for a difference?

[DannyBadorine]

The USB interface clocks the data by way of packet requests.  Therefore, any claims of “lower jitter” regarding a fancy USB cable are ludicrous.

I agree with this (though I've never tested high priced digital cables of any kind).  Is there any way that there can be an error in the movement of packets through the cable?  Are there digital reflections within the cable?  What if there is some kind of increased resistance?

[whell]

I agree with this (though I've never tested high priced digital cables of any kind).  Is there any way that there can be an error in the movement of packets through the cable?  Are there digital reflections within the cable?  What if there is some kind of increased resistance?

What's a "digital reflection"?  In terms of resistance, digital cables that are specified for 75 ohms are fully capable of moving a digital without issue.

[DannyBadorine]

I am no expert in it, but when dealing with multiple amplifiers in a system where we are sending all digital signals to them, we put an impedance plug at the end so we can minimize reflections.  Here's the thing; I don't completely understand the science, but I have seen problems that occur without the plug.  It might also have to do with the amplifiers losing digital sync due to mismatched impedance.  But again, I operate the equipment, I don't design it. 
Here's an article on digital reflections:
https://www.audiosciencereview.com/forum/index.php?threads/technical-article-digital-audio-cable-reflections-and-dacs.7159/

[Zuman]

I know nothing about the legitimacy of the claims made by cable manufacturers and have not personally invested in expensive cables, but many manufacturers talk about the introduction of "distortion" due to "inferior" materials, strand configuration, shielding, or dielectric. If the fundamental digital outcome is not corrupted by compromised materials, design, or manufacturing in USB cables, is it nevertheless possible for "bad" cables to pick up and transmit any kind of harmful noise to the devices they connect while still transmitting an accurate bitstream?
If the science and engineering is as open-and-shut a case as you've outlined here, I find it hard to reach any other conclusion than USB cable manufacturers who claim otherwise are bad people who are intentionally lying to us and should not be trusted in their claims about speaker cables, other interconnects, and power cables, too.

[I.Greyhound Fan]

I own several USB cables ranging from $40 to $225. They all sound different and it is not subtle.  They can also sound different on different DAC's.  3 years ago we did a usb cable shoot out with cables in the $40 to $600 range and the results were eye opening as there were big differences.  The best sounding cable was a WW Starlight 7 Platinum which sells for $600.   The worst was a $40 Pangea, it was thin, bright and not really listenable with my Luxman DAC.

Anyone is welcome to come to my house in the Twin Cities and hear the differences with a Luxman and Qutest DAC.

[dpatters]

Yikes! Another usb cable discussion.

Don P.

[charmerci]

Yikes! Another usb cable discussion.

Don P.

Years ago, I was in the "cables don't make a difference in the sound" camp. I bought a decent set of cables cheap with ZERO thoughts and NO expectations that it would make a difference. Period. It does.


But reading about your system, apparently you do too, so I guess it's the discussion you're yikes-ing about. 

[DannyBadorine]

I would think that it could be measured since it's just transferring packets of zeros and ones.........couldn't we see the jitter or change in the packets from one side of the cable to the other??  It's going to take someone smarter than me to figure it out.
I have never A/B'ed USB cables to hear a difference.  I have never tried higher quality power cables either.  I would be open to trying it in a blind test.  I have definitely heard the difference between different clock sources on A/D converters and it's not subtle. 

[whell]

I own several USB cables ranging from $40 to $225. They all sound different and it is not subtle.  They can also sound different on different DAC's.  3 years ago we did a usb cable shoot out with cables in the $40 to $600 range and the results were eye opening as there were big differences.  The best sounding cable was a WW Starlight 7 Platinum which sells for $600.   The worst was a $40 Pangea, it was thin, bright and not really listenable with my Luxman DAC.

Anyone is welcome to come to my house in the Twin Cities and hear the differences with a Luxman and Qutest DAC.

The difference you're hearing has nothing to do with the cables.   It's all about the underground resonances from the Mesabi range iron ore that warp the propagation of digital signals.