Quote:
Originally Posted by audioengr  The difference between a cheap USB cable performance and a really good USB cable performance is the amount of jitter that it adds. Jitter is added through several mechanisms:
1) losses
2) Inter-symbol interference (ISI)
3) reflections due to impedance discontinuities
All of these have an effect at the USB receiver.
Now, whether or not this affects the audio stream depends on the USB interface. If it is an optimally implemented Asynchronous or block-transfer protocol, then the jitter does not matter. It is buffered at the receiver just like a disk drive or printer. The master clock is in the receiving device.
However, if it is a Adaptive-mode USB protocol, then it is sensitive to the jitter as this is passed through a PLL that recovers the clock. The master clock from the computer is used. The USB cable will have an effect in this case.
This does not mean that one USB protocol will necessarily sound a lot better than the other. All three USB modes be excellent, with jitter on the threshold of audibility. The ultimate performance depends on the clock quality and implementation.
Steve N.
Empirical Audio
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Jitter on the threshold of audibility, what are you talking about? I've never read such rubbish. I take it you have proof of this and jitter measurements for the cable you are peddling with comparisons of the jitter caused by cheaper cable?
I would also like you to explain how reflections in the USB cable are going to have any audible impact on sound quality whatsoever.
Perhaps you'd like to explain how a PLL recovers the clock from the computer, rather than the originating ADC or masterclock. And while you're at it explain how a PLL does not reject the jitter caused during digital transfer, in whatever USB mode.
I don't know what your three points above refer to but it's nothing to do with digital audio, it's complete nonsense. I would have hoped that you had seen the error of your ways when Dan Lavry destroyed your arguments and exposed you as the charlatan you are. Instead, you've decided to come here to try to fool the consumers as the professionals saw right through you.
If it were up to me I'd have people like you fined or imprisoned for spouting pseudo scientific BS in a deliberate attempt to mis-lead consumers into buying your stupidly priced cable which have no benefits whatsoever, except to your bank balance.
I look forward to your answers to my questions above but we both know that you will do or say anything to avoid answering with accurate facts and figures.
G
