USB cable hype


Can someone explain the need for expensive USB cables for short runs? The only parameter of concern is impedance. I personally have verified error-free transmission in the Gbps range regardless of cable make/model as long as the cable length is short. There is no magic. It is just about impedance control to minimize loss and jitter. This is inexpensive in the MHz range. I will pay more for a cable that it is well built. I will not pay more for hocus pocus.
axle
Hi Kijanki, I agree with everything you said except for this one thing: "...jitter does not even apply here".

Just because the source clock isn't used inside the DAC doesn't mean that it has no effect. The DAC clocks data only after it reaches the DAC. The source clocks data up to that point. Source clock jitter combined with cable jitter may err a bit before it reaches the DAC.

For short cable runs, bit errors induced by the cable are unlikely. For long cable runs, bit errors are inevitable. Therefore, the longer the cable and more marginal the source, the more the cable matters for both function and SQ.

Of course, as you mention, a cable may also help SQ by isolating the signal from various noises.
Here is a link showing a good USB eye vs bad eye.

http://www.embeddedstar.com/weblog/2009/06/07/industrial-usb/

Here is a USB chip vendor's failing eye diagram.

http://e2e.ti.com/support/arm/sitara_arm/f/791/p/283089/987150

One eye is open. The other two eyes are closed without a long cable. The good eye doesn't need any help. Any cable will do. The bad eyes need all the help they can get. The cable is critical. Reality is that you aren't searching for that magic touch (whatever that means). You are searching for the cable that does the least harm. Silver will 'sound' better because it is faster. But silver won't sound any better for the open eye.
I have two extra pair of Wireworld Starlight and one Pangea AG USB cable. I cannot tell the difference between these and the basic monoprice cables except that the more expensive ones seem more sturdy. Sound-wise, not a whit of difference. I wish I were able to so I didn't feel dumb spending money for what is basically a give away item.
Lse thanks for the info tho sorry for your situation having spent the extra money with no difference in sound, you have helped me as I will not spend the extra because I have the Monoprice usb already. Also fwiw I think it sounds terrific and I know there is a difference between cables as I have a cable (unmarked) that is far better than a generic usb that I used to use (more body, fuller bass). The Monoprice has terrific bass and smooth detailed highs.
Axle, cable bad enough to corrupt bits would be disaster
since each frame contains checksum and would be dropped. As
I understand it each frame is delivered every millisecond
and starts with unique bit sequence signifying start of the
frame (SOF) followed by music samples (about 2x44
for redbook playback) and then followed by the checksum.
When even one bit is wrong checksum won't match and DAC will
drop whole frame (2x44 music samples) since it does not
resend frames. On the other hand I see possibility of
vendor specific design that resends frames eliminating bit
errors completely.