Do USB cables make a difference? Does length matter on them beyond say 10 feet?

Lee · Mar 14, 2011

Question for the experts here. What is your view on the sonic differences of USB cables?

I am about to attach a Musical Fidelity V-Link box so I can connect my Benchmark DAC1 to my new Mac Mini.

I'd like to do two things:

1. Use a Belkin USB cable is that is adequate.

2. Use a 9-10 foot run of it to connect to the V-Link box.

Does either #1 or #2 create a sound issue?

Thanks for the help!

Vincent Kars · Mar 14, 2011

The USB standard says 3m for low speed devices.
Some advice to use a short cable for the sake of sound quality

Others advice to keep a safe distance between the PC and the DAC
The normal audiophile confusion.

You might fool around a little with short/long USB and long/short SPDIF
Any certified USB 2 will do, can be used to connect your HD as well.
http://thewelltemperedcomputer.com/HW/Connect/USB_connect.htm

Lee · Mar 14, 2011

Thanks Vincent. My listening chair is around 6 foot from the Maggies and 8 feet from the equipment rack. I have the mac mini next to my chair and I kinda like it there. I can also move the mini to the rack and run a long video cable. But then I lose the convenience of ripping cds into the mini from my chair.

RBFC · Apr 11, 2011

Does anyone know about the Acoustic Revive USB-1.0SP USB cable? It has two USB "A" plugs, one for power and one for signal, with each having its own wire for the length of the run. The two leads merge into the USB 2.0 "B" plug at the DAC, thus separating the power and signal leads for the entire length of the cable. A friend asked me about this cable and I would like to hear if anyone here has any knowledge of it.

Thanks,

Lee

ar-t · Jun 3, 2011

Oh, boy.........a thread about cables, that is technical in nature.

Ok, the USB spec calls for a cable that is less than 26 nSec, transit time. They insist on this, so that the reflections will die down, properly, before the next chunk of data comes down the line. So, this limits us to around 15', or so. We have measured several different twisted pairs, at that length. Most met the spec, a few didn't. Mind you, these were cables not specifically designed for USB. They were merely twisted pairs, that we had reason to believe were the right impedance.

Which is 90R.

Which is a really odd value, for twisted pairs. 110R-128R are much more common. (USB throws an additional monkey wrench, into the mix, by adding an additional twisted pair, for power and ground.)

So, as part of our ongoing research, to find what wire works best for USB, we tried several cables we thought would work. Most were the wrong impedance. (Surprise, surprise. I wonder what the guys who thought up USB were thinking about. Maybe they used some odd method, to measure impedance, once the additional pair for power and ground are thrown into the mix.) Having found ones that were close enough, we measured transit time. The few that did not pass were barely out of limits.

So, there you go.............the reason why your USB cables should be less than 15'.

Will they sound better, shorter or longer? No way to tell that, by our fancy measuring gear. Not even going to speculate.

ar-t · Jun 3, 2011

RBFC said:
Does anyone know about the Acoustic Revive USB-1.0SP USB cable? It has two USB "A" plugs, one for power and one for signal, with each having its own wire for the length of the run. The two leads merge into the USB 2.0 "B" plug at the DAC, thus separating the power and signal leads for the entire length of the cable. A friend asked me about this cable and I would like to hear if anyone here has any knowledge of it.

Thanks,

Lee

I can not comment, on that specific cable. I have seen some other brands, that do that. As someone who spends a lot of time measuring cables, I like the idea. In theory, it provides a better chance of getting a twisted pair, with the right impedance, to carry the data. The two wires that carry power and ground are not as critical. So, why try to stick them all in one jacket? Especially if you are trying to get the best there is.

Orb · Jun 4, 2011

ar-t said:
Oh, boy.........a thread about cables, that is technical in nature.

Ok, the USB spec calls for a cable that is less than 26 nSec, transit time. They insist on this, so that the reflections will die down, properly, before the next chunk of data comes down the line. So, this limits us to around 15', or so. We have measured several different twisted pairs, at that length. Most met the spec, a few didn't. Mind you, these were cables not specifically designed for USB. They were merely twisted pairs, that we had reason to believe were the right impedance.

Which is 90R.

Which is a really odd value, for twisted pairs. 110R-128R are much more common. (USB throws an additional monkey wrench, into the mix, by adding an additional twisted pair, for power and ground.)

So, as part of our ongoing research, to find what wire works best for USB, we tried several cables we thought would work. Most were the wrong impedance. (Surprise, surprise. I wonder what the guys who thought up USB were thinking about. Maybe they used some odd method, to measure impedance, once the additional pair for power and ground are thrown into the mix.) Having found ones that were close enough, we measured transit time. The few that did not pass were barely out of limits.

So, there you go.............the reason why your USB cables should be less than 15'.

Will they sound better, shorter or longer? No way to tell that, by our fancy measuring gear. Not even going to speculate.

Good info.
Just to add Paul Miller did an investigation into USB, and one article included looking at the USB cables (the tests involved his jitter analysis software).
What he found was major inconsistencies between various cables, with one situation the 5m cheap USB cable outperforming a 1m "high quality" by a good margin.
The jitter was large enough that in theory it could affect sound quality.
Seems a bit of luck when purchasing USB cables, without as you say measuring and listing them.

Cheers
Orb

Phelonious Ponk · Jun 4, 2011

I have an Audioquest usb cable between my MacBook and my printer. No measurable impact on spelling or grammar, but I don't read measurements. The kerning has tightened up significantly and I see an open and airy expansion of space between words resulting in much better legibility. A word is a word; complete, discrete, palpable. Only the most resolving papers will reveal these improvements, but for those who seek the best? Highly recommended.

Tim

DonH50 · Jun 4, 2011

No mention of leading? Perhaps you need a better monitor, cryogenically treated, of course...

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Do USB cables make a difference? Does length matter on them beyond say 10 feet?

Lee

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Vincent Kars

WBF Technical Expert: Computer Audio

Lee

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RBFC

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ar-t

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ar-t

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Orb

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Phelonious Ponk

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DonH50

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