Phil Leigh;686276 Wrote: > Which is why it is important to galvanically isolate the Touch. There > are three routes in: > 1) the spdif coax connection - noise can be transferred back from the > DAC - use Toslink or at least use a DAC that has a transformer isolated > input stage > > 2) the ethernet connection - use wireless, or use a properly isolated > ethernet cable (not screened at both ends) or use an ethernet isolater > like this: http://www.blackbox.co.uk/product/sp426a/4/6/1/ > 3) the power supply
Thank you for the advice. If I understand you well, if those 3 conditions are not perfectly met,you admit implicitly that some kind of noise can be transmitted from the source to the DAC output. However these consideration seems to be based on the assumption that the noise is coming from external sources (ground noise from cables and power supply) and not from the signal path. But considering that a digital signal is a perfectly square wave + noise, we should also consider that some of the noise from the signal path can also be transferred to DAC output. Sources of this "added" noise are typically jitter, temperature noise and any kind of signal interference caused by PSU, CPU processing,... Even with signal reshaping, the return path for this noise should be isolated from DAC output. In the same logic, I don't know how optocouplers work, but do they produce perfect square waves at their electrical output as well? if not, they would also transfer the noise from the signal path, even if they provide perfect galvanic isolation. I don't want to raise polemic, but from my point of view, there are a lot of unanswered questions about handling of the noise in the reconstruction of the analog signal that I can not admit the "bit perfect" argument alone to conclude that a digital source noise has no impact on analog output noise. And if I remember well Phil, you are the only one on this forum that objectivated by quantitative measurements that tt3.0 mods have an incidence on DAC output signal (weither it is audible or not is another topic). -- evdplancke ------------------------------------------------------------------------ evdplancke's Profile: http://forums.slimdevices.com/member.php?userid=43147 View this thread: http://forums.slimdevices.com/showthread.php?t=91322 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
