Excellent info and summary - thanks John! I also found your Audio Asylum post below, which I believe helped me further understand the situation - especially (as you also stated above) that the S/PDIF performance of the Touch is likely performing better than that of the Squeezebox Classic due to the lack of a S/PDIF output filter, and thus better resulting compatibility with the digital receivers in certain external DACs...
JohnSwenson Wrote: > I have actually measured an SB3 (not a Duet) and the jitter in the SB3 > itself is in the 50-60ps range, very different from the cited > measurement. The 320ps number was not actually measuring the jitter of > the S/PDIF signal, but rather looking at the distortions of the analog > signal coming out of a DAC attached to the SB3 and infering the jitter > from those distortions. > > Its a subtle distinction, its not the jitter of the SB3, but the jitter > of the recovered clock in the receiver. It includes jitter added by the > receiver and any problems in the connection between boxes. This is > actually the problem here. > > The SB3 contains a filter on the S/PDIF output designed to reduce EMI > which unfortunately messes up the waveform which prevents the PLL in the > receiver from extracting a low jitter clock. > > This has a couple of interesting ramifications: the jitter of the > recovered clock is going to be very sensitive to the receiver used, > different digital cables make a big difference here, and significantly > decreasing the actual jitter (by using better regulators, better > oscillators etc) won't make all that big a difference. > > BTW getting rid of that filter radically improves things. > > This sensitivity to external factors I think explains a lot of the > disparity in reports about using the SB digital out. > > John S. -- NewBuyer ------------------------------------------------------------------------ NewBuyer's Profile: http://forums.slimdevices.com/member.php?userid=7862 View this thread: http://forums.slimdevices.com/showthread.php?t=70167 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
