High End USB Cable?

[jkeny]

I did read the links. What I am asking is "What equipment and methodology can be used to statistically determine the differences between USB cables?."

Ok, so it was a genuine question - sorry!
I guess the only way to analyse the difference between USB cables where digital audio is concerned is to examine the electrical waveforms emerging from the end of the cable & not just the digital logic that these signals represent. Not something that I have come across much, however.

 

[rrr]

Ok, so it was a genuine question - sorry!
I guess the only way to analyse the difference between USB cables where digital audio is concerned is to examine the electrical waveforms emerging from the end of the cable & not just the digital logic that these signals represent. Not something that I have come across much, however.

We are paying more than $15,000 for some DACs and buying $1,000 cables to go with them. I can hear the difference in the DACs, which are crammed full of costly electronic gadgetry so I can justify a $15,000 DAC and even a $17,000 SACD transport more easily than a thousand dollar piece of wire that looks essentially like any other USB cable and I am just wondering if our ears are deceiving us when it comes to the relative values of different USB cables. It would be helpful to see some sort of technologically based factual method that describes the difference in these two pieces of wire.

 

[mep]

Well... many of us are always willing to learn so tell us what equipment and methodology can be used to quantify the relative ability of various different USB cables to pass accurate and consistent data?

I wasn't addressing why different USB cables can sound different. I was only addressing your comment about not hearing anything about cables used in critical applications.

 

[Scott W]

Hello rsorren,

PM me. I can help with a LH Lightspeed demo.

Regards,
ScottW

 

[jkeny]

Here's a paper which might shed some light on the differences between cables. It deals with shield current induced noise in balanced audio cables. Measurements done out to 4MHz frequency. This is for twisted pair shielded cables - extrapolate to USb cables which include 5V & ground wires

Essentially, a large number of factors induce current in the shield which changes with frequency, not least the makeup of the shield itself - for instance using a drain wire for ground is not a good idea.
http://audiosystemsgroup.com/AES-SCIN-ASGWeb.pdf

 

[Whitigir]

I made several USB cables myself, and I can attest to that USB cables introduce the improvements, changes, affects even more than analog cables (the speakers or headphones cables). Constantly observing cables of different materials yielded the same results

 

[DonH50]

I did read the links. What I am asking is "What equipment and methodology can be used to statistically determine the differences between USB cables?."

To "statistically" test a cable the equipment I would use would be a bit error rate tester, i.e. a BERT, and a digital sampling oscilloscope (DSO) to assess jitter, edges (rise/fall times), and other metrics using eye diagrams, histograms, FFTs, and so forth. Same way I test high-speed PCIe, SAS, and other serial links. This equipment can detect and show not only "digital" bit errors but also corrupt pulses, signal glitches, and so forth.

 

[YashN]

I made several USB cables myself, and I can attest to that USB cables introduce the improvements, changes, affects even more than analog cables (the speakers or headphones cables). Constantly observing cables of different materials yielded the same results

A USB cable is an analog cable.

 

[Whitigir]

I see, I appreciate for the respond. It makes senses as USB cables brings a lot of changes and improvements to the system

 

[YashN]

It makes senses as USB cables brings a lot of changes and improvements to the system

Actually, that's one of the reasons you can find differences whereas technically, in a pure digital systems, there shouldn't be any. In the usual implementation, the signals on the cable are voltage levels with a ramp up and ramp down time. The digital form is recovered as bits on the USB receiver where the voltage levels (high, low) are compared to reference levels.

That intermediate signal traveling on an analogue cable can be subject to interference.

 

[pielectronics]

In general the sound quality may not obliviously different when you using high end usb cable. I have a high end piarmor cable and I may not able to find a big difference between them.