sfraser Wrote: > Maybe I don't understand everything that is involved here, but I often > wondered why jitter is an issue at all between components such as a > SB2/3 and a DAC or in my case my Bryston Suround Processor preamp. If > the physical interconnect's and coax/optical cables create jitter or > timing issues, why don't more DAC's have buffer space? With the prices > companies are charging for these devices, surely a relatively cheap fix > would be to provide sufficient buffer space on your digital input of > your "DAC Device", and then re-clock? Is this to simple of a fix? > > Scott
Good question, and I don't know the state-of-the-art in DACs, but the older ones definitely do try to clean up the clock using a PLL (phase-locked-loop). They have to let the source clock (the SB3, e.g.) determine the clock rate itself (in other words, you cannot have an independent clock on the DAC), since small rate differences will eventually over or underflow the buffer. A PLL uses the source signal as the clock rate, but it cleans up the jitter by evenly spacing the samples (in essense, filtering out the jitter). Audiophiles and stereo salespeople say that it's still a problem, since the more "correction" the DAC has to do to a jittery signal, the more new jitter (or residual old jitter?) is introduced indirectly. If the source is very clean, as the theory goes, the milder amount of cleanup causes fewer side effects electrically and the whole system will produce a cleaner output. The same theory is proposed to explain why even corrected errors from CDs in the transport cause degradation of sound quality - the act of correcting stresses out the system and creates jitter, electrical noise, or whatever. Not sure I really believe these theories, but that's where the whole thing goes into the realm of "hard to prove." -- LavaJoe ------------------------------------------------------------------------ LavaJoe's Profile: http://forums.slimdevices.com/member.php?userid=2331 View this thread: http://forums.slimdevices.com/showthread.php?t=18772 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
