Yes traditional SPDIF receivers are not good at recovering the SPDIF and creating a clock, as they rely on an analogue PLL - and the data itself modulates the clock, so you get signal correlated jitter which is extremely audible. But my SPDIF receiver is all digital, and relies upon the low jitter local clock, and does not create signal correlated jitter. The SPDIF receiver creates I2S data, with zero signal correlated jitter; plus a word clock, exactly as if it was transmitted via a real I2S connection.
But, the word clock - whether from a direct I2S or SPDIF, still will have source jitter. And this must be eliminated - and that is the job of my DPLL, which completely eliminates any source jitter. So there is absolutely no benefit in using I2S, so no need to go to the complexity of HDMI - the video noise would cause extra problems to worry about too.
Hi Rob, sorry for picking up on what you said a year ago, as I found this clock topic very interesting and could potentially save me a lot of money.
My current signal path is:
Synology NAS (storing my library and running Roon Core) > Ethernet > dCS Network Bridge > single SPDIF RCA out with a BNC adapter into > Chord Qutest > preamp > power amp
I have been concerning the SPDIF connection between dCS NB and Qutest, as I also read SPDIF degrades SQ because the source (in my case the dCS NB) controls the clock, not the DAC. Plus that I cannot fully utilize Roon’s RAAT framework that allows the DAC to control the clock for the entire digital signal path, as Roon can only recognize my dCS NB but not Qutest due to the SPDIF connection, not to mention that the SPDIF output from dCS NB caps at 192/24 and DSD64. Also the RCA to BNC adapter may degrade SQ too. So I feel that I have wasted the potential of both equipments and have been itching to buy the new dCS Bartók streaming DAC to replace the NB+Qutest combo.
However, based on what you said above, it seems to me that no matter how good or how bad the dCS NB handles the clock, or how bad the SPDIF connection mess it up, it doesn’t really matter as Qutest will eliminate any source jitter from the streamer anyway. Am I interpreting what you said into my setup correctly?
What would be your guess or understanding on dCS’s SPDIF implementation on the Network Bridge? Does the RCA to BNC adapter degrade SQ technically?
Putting the DAC quality aside, do you think replacing the dCS NB + Qutest combo with a 2-in-1 streaming DAC (Bartók in this case) would improve SQ? I heard the streaming section inside Bartók connects to the DAC section via I2S, which is superior to SPDIF and in that case Roon can see the DAC section too.
Also speaking out loud and this might be a very stupid question - can I custom order a pair of Coaxial cables, terminated with AES on the source end and with BNC on the DAC end, so that I can use dCS NB’s best output and Qutest’s best input, in order to eliminate the restrictions and improve SQ? Impedance mismatch could be an issue...
Thanks Rob or any experienced user who can help me understand all these!