How to improve Jitter issue via USB/ETHERNET ?

[Jean-Marie]

Hi, worth knowing about jitter etc!
http://www.jitter.de/english/engc_navfr.html

Thanx for the link. These pages should be read by everyone who wants to contribute to any thread in 'Streaming' and 'Tweaker's Corner'. A lot of questions are answered there...e.g. why USB-cabels all sound different (and more).

gui

Perhaps predictably, I beg to differ.  The article is interesting but as far as I can see it talks specifically about clock jitter in S-P/DIF and Toslink, where the audio sample clock has to be recovered from the input signal.  It is misleading to think it's directly relevant to USB and Ethernet, because these protocols are clocked completely asynchronously to the audio samples; the samples are not expected to arrive at intervals of the audio sample period.  The concept of clock or inter-sample jitter doesn't make any sense - it's simply not defined - for samples delivered asynchronously like this.  In fact you get bunches of samples all at once at more or less predictable times (more predictable on USB, less so on Ethernet), and it's up to a higher-level agreement between the sender and receiver what the time period between individual samples is supposed to be.  The receiver then has to generate an independent clock at the agreed rate to play the samples; that clock will have some degree of jitter, but in any reasonably-designed system that should be completely independent of the USB or Ethernet clock.  There could be jitter in the USB or Ethernet clock, of course, but either that results in packet errors - usually meaning drop-outs - or it has no effect on higher layers.

Absolutely, and it is interesting to note that in the blue pill vs red pill case, spdif was used, therefore a synchronous coupling between the DAC and the player. 

Jean-Marie