Why do digital coax cables matter?

We need to look at the whole system. Cable impedance is designed to 75 ohm to match everything else in the signal path. However, everyone knows nothing will be perfect, so it comes down to how close is the actual impedance to 75 ohm. How about the connectors, trace of PC board, etc. What matters is at the point where the clock information is recovered from the signal. If it is not exactly 44.1kHz, there is jitter and it causes distortion to the audio signal. Therefore, cable quality matters if everything else in the system closely matches to 75 ohm. If by accident, everything matches to 70 ohm, it will be good too, but chance for that to happen is very small.

Therefore, professional studio use master clock such that only the 1 and 0s are decoded from incoming signal and not the clock information. In that case, jitter can be minimized to just between the DAC and master clock generator. Then most effect from the cable can be eliminated. A few high end decoder manufacturers adopt this setup like Esoteric and DCS for home use. It is a much more expensive solution, but it works.

Cheers and enjoy music

Digital cables are fundamentally different than analog cables.....the cable is an electrical transmission line at 44+ kHz. The 75 ohm impedance match at each end is critical for jitter, minimizing reflections, etc. BNC connectors are made for this, but Canare makes one of the only 75 ohm RCA connectors available......I've tried 'em and they sound better. Any good video cable in between works well, but the cable pedigree is much less important than with analog cables.

They do matter just listern to your ears + trust them,
I have tested many many digital coax cables + i found the more money i spent the better they sounded to me. this INMO
Opinan is down to the design,materials + connectors been,
used. the best digi coax cable i've ever tested + still own,
it the audioquest "eagle eye" at £700GBP per mtr!, it is just the business, solided silver conductor mutli sheilding,
+ DBS battery pack, its not hog-wash it works period!!!.

Almarg wrote:
"Do you feel that the following may also be significant contributors to sonic differences between S/PDIF interconnects, at least in some systems?

6)Differences in noise-induced jitter, due to ground loop effects and/or RFI/EMI pickup, both of which may be sensitive to cable differences.

7)Differences in radiated RFI, that may affect circuitry in the system that is not directly related to the S/PDIF interface."

These are both potential contributors to jitter, although #6 is not directly related to cable quality, and # 7 is mostly a function of the receiving device IMO.

As for cable pricing, I have found that in general cables below the $500 mark for 1.5m length sound about the same. Significant improvements are not realized until one spends more than $500. This is when you start to get the more exotic constructions, conductors and dielectrics, as well as better shielding. Just my experience.

Steve N.
Empirical Audio

Mapman wrote:
"on the several occasions where I have compared different digital cables going into my DAC(s), if there was a difference, it was not enough for me to take clear notice or even care. I know that in theory different levels of jitter is the result and that jitter level matters. But does it really in practice?"

Perhaps you didn't test the right cables, or your preamp creates enough distortion, noise and compression that you dont hear the benefits because they are masked. This is fairly common when using an active preamp. I dont use a preamp, so I dont experience this masking anymore. It's a system after all, so every component and cable matters.

Steve N.