Interesting measurements Sean, if you still have access to the measurement apparatus, I'd be interested to see those jitter measurements replicated at the DAC clock input.
I wouldn't be surprised if the CPU / internal digital activity had a greater effect at that point, since you then have the cumulative effects of the additional circuitry and the PSU interactions (some of which is related to CPU activity, I suspect) on that same clock signal. I'd tend to agree with MarcBernard's observations too, that you can generally assume a 120dB dynamic range + reserve margin when choosing acceptable jitter specs whether the system actually acheives this in measurement or not. Certainly my experience is that anything to reduce jitter is audible, even in the best engineered of devices, even when at very low levels already. I'm not convinced of the evidence cited by the late Julian Dunn, or the other figures quoted. The reality is jitter is one of the most critical issues to deal with, in my view, from a sound quality perspective, certainly my onw mods on an SB2 confirm that improvement on those already good figures, is clearly audible. One thing that is important though is the jitter spectrum - it's one of the things Guido has openly talked about, he openly admits the clock's he sources are not specially designed, but they have been chosen from a range of candidates, most of which sounded far worse, as much due to the different jitter spectra ans any absolute jitter number. As mentioned, Guido is very approachable and open, if a little busy, so it may be worth talking to him, or reading some of his output in places like diyudio.com. Andy. Andy. -- Andrew L. Weekes _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
