achri-d;253632 Wrote: > > It goes silent. > OK good... next thing to test is to try listening to Transporter's _analog_ outputs while it is being fed by the 48KHz word clock. They should operate both in 44.1 and in 48KHz mode. Then if you disconnect the word clock while playing, the analog outputs should either go silent or speed way up or down.
Also, try playing both 44.1 and 48 KHz tracks while in 48KHz mode. The 44.1 tracks should sound sped-up. > > Yes it is a manual setting. Please, notice that I use a DAC and en > external clock, i.e. two units. ?!? Why? Such a configuration should only be used if you have some requirement to synchronize multiple _source_ components, perhaps for editing purposes. It is the MCLK (eg 11.2896MHZ) signal that actually drives the internal operation of a modern DAC chip, and the whole point of word clocking (for the purpose of reducing jitter) is to put that clock as close as possible to the DAC chip itself. A PLL is absolutely _terrible_ at generating a master clock from a word clock, compared to generating it directly with a crystal. But that is not even the only source of jitter - you are also accumulating it in all the connections between this equipment, and in the clock source device itself, as it has to divide a crystal-generated clock internally to produce that low word clock frequency. I am not aware of any situation where a word clock would be advisable for driving a DAC. You will get jitter much worse than anything you'd get even from traditional s/pdif master->slave clocking.... i.e. this is not only defeating the jitter eliminating mechanism of the word clock interface, but is actually making the jitter far worse even than plain s/pdif. You are probably running your DAC on a few hundred picoseconds of jitter, as opposed to the 30ps or less that would come from a good quality internal oscillator. > The clock (square waves) is fed to the Transporter using a standard 75 > Ohms cable with BNC connectors. No- not S/PDIF format. That is, one > cable feed the clock TO the Transporter, and another (S/PDIF) sends the > data FROM the TRansporter to the DAC. > > Rgds. That's fine... but driving the DAC from a word clock signal is not OK. The problem could in fact be that the jitter is so high that the system is on the borderline of being able to operate at all. Have you tried hooking things up in the usual word clock configuration where the DAC (not a separate box) is the clock master? Also, have you talked to dcs about this issue? I'm not just trying to point fingers here, but without having the equipment on-hand this is very hard for me to diagnose. They may be able to provide some additional insight here. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=39770 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
