opaqueice;175845 Wrote: > Well, not really. Adding noise to the digital signal (and yes PF, by > digital signal I obviously mean the electrical S/PDIF signal > transmitted along the wire, not the abstract sequence of bits) will > change the analogue output of the DAC. This is called jitter; it > results from the fact that (most) DACs use the transitions in the > digital signal as a clock. If there is noise it affects the derived > time of arrival of those transtions, resulting in a jittery clock, > which in turn results in a distorted output waveform. The difference > between that distorted waveform and the ideal is nothing but a form of > noise at the analogue output - and in fact that's exactly what > Stereophile measures in their tests and refers to as jitter (but it's > NOT what Sean measured - he made a direct measurement of timing > variations in the digital signal). > > > > In this case it is different - see my post above - but not completely > so. My point stands - it stretches credulity to the breaking point to > think that some jitter-induced noise overlaid on much louder music is > more audible than similar noise amplified maximally and played against > silence.
Distorted yes...noisy as in "hissy" or "hummy"...no. I don't really have any idea what jitter-induced noise is in any analogue sense... That's kind of the point of digital really, isn't it? You can mess with the analogue version of the digital signal (ie the spdif signal)as much as you like but so long as the right bits arrive, no "noise" or anything else is added. Of course if the clock recovery is getting messed-up you get jitter (not noise). That's what I hear with the wall wart in or out - zero "noise" in either case, but something "different" in the reproduction of actual music. None of what I am saying is relevant to the performance of the internal SB DAC which may well have a higher or lower analogue noise floor with different supplies - I don't know. -- Phil Leigh ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
