firedog;686274 Wrote: > I stand by my claim. The Benchmark doesn't eliminate jitter. It's a > marketing claim. If it is fed a jittery signal, there are methods for > improving the result, but the jitter isn't "eliminated". In real life > there isn't digital audio with NO jitter - by definition. Low jitter, > yes. NO jitter, sorry. Try to find someone in the field other than > Benchmark that thinks jitter can be totally eliminated - you won't. > Because the D/A conversion will always have at least a little. > > http://www.head-fi.org/t/465286/does-the-benchmark-dac1-or-any-dac-eliminate-all-jitter > > http://www.computeraudiophile.com/content/Reclocking-DAC-immune-transport-jitter
I think there is a confusion here which can only be overcome by tightening up slightly what we are talking about. The issue is whether a dac can perform independently of (ie be unaffected by) transport and interface jitter. Conventional digital audio theory has it that it can and can fairly easily. This is the raison d'etre of digital communications- the information can be perfectly recovered despite noise. Benchmark have shown results from hugely long cables which audiophile theory would suggest must be terribly jittery but leave no imprint on the output. Slightly confusingly the typical j test shows the total jitter at the anlog out and does not distinguish between interface jitter and the inherent jitter of the dac. It is true to say that a dac is bound to have some *inherent jitter* which will affect D/A conversion- this must be true becasue the DAC can't have a 100% accurate clock. BUT a dac *can* be immune to interface/trasnport jitter within reason. Within reason here means within several nanoseconds at which point it is impossible to read the data accurately because the clock transitions actually overlap. Many DAC manufactuerers and text books will make this claim. I am pretty saue i have quoted them on this forum some time ago. Look at this quote from the naim website about the naim dac http://www.naimaudio.com/hifi-product-type/583 "In terms of system topology, the DAC's rotating memory is analogous to a rotating CD feeding raw data to be reclocked. The rate at which the memory fills and empties is controlled by the DAC automatically selecting the oscillator that matches the average incoming clock frequency. The data entering the downstream digital filtering and DAC chips is then completely isolated from the incoming S/PDIF jitter." Incidentally If you look at the results from the weiss 202 on the sterophile website it appears to all intents and purposes to have no discernible jitter. -- adamdea ------------------------------------------------------------------------ adamdea's Profile: http://forums.slimdevices.com/member.php?userid=37603 View this thread: http://forums.slimdevices.com/showthread.php?t=93232 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
