Why do digital coax cables matter?

Dcbingaman wrote:

'Fortunately, HDMI 1.3+ provides for this and is generally superior to any SPDIF interface, (even with million dollar cables), for this reason. Buy an Oppo BDP-95 and a DAC with an HDMI 1.3 input (Meridian HD621), and you won't have to worry about jitter.'

You must listen to different HDMI stuff than me. On my NAD M51 SPDF and USB easily bests HDMI. And when fed with an Off-Ramp which has jitter below 10ps you can easily hear the improvement over any other method. HDMI is far from jitter free - not by a long shot.

I hasten to add it probably has nothing to do with the interface per-se but what's feeding it via the interface.

Also anyone one who thinks there is any method available today where you don't have to worry about jitter they are whistling dixie. Even on sources with jitter below 10ps like the Audiophello 2 and Off-Ramp you can easily hear the difference.

I have a Playback Designs DAC that they advertise as jitter immune. Even on that DAC you can hear the difference when fed with a low jitter source like an Off-Ramp - although it is not as great as with other DAC's - but it is still there.

Thanks
Bill

Rower - if you are getting bit errors, the eye pattern is so bad that jitter is the least of your concerns.

"reclocking the data at the DAC is the key to superior reproduction"

You would think so, but unless you can synchronize the source to the DAC using word-clock, it is not the best solution. Very few sources have this capability.

You will achieve much lower jitter making the source jitter low and feeding it to a DAC without internal reclocking. This is because all of the techniques for asynchronous reclocking for jitter reduction in DACs are inferior, both PLL and ASRC.

Steve N.
Empirical Audio

...http://www.stereophile.com/reference/1093jitter/...

This is a pretty good description of what is going on. It is an older article but still relevant to many points.

Was just reading about how 1.5m is the best length for a digital cable. Something to do w/ reflections. I read somewhere else that all interconnects can benefit from being 1.5m. Somehow that doesn't sound right to me. So, is it true- will 1.5m RCA interconnects going from my DAC to my pre amp sound better than the 2 ft length I am currently using? Thanks

Mrblackcrow 8-26-2017
I read somewhere else that all interconnects can benefit from being 1.5m. Somehow that doesn’t sound right to me. So, is it true- will 1.5m RCA interconnects going from my DAC to my pre amp sound better than the 2 ft length I am currently using?

You are correct about that not sounding right. The 1.5 meter length recommendation that is often seen for digital cables has no relevance whatsoever to cables conducting analog audio signals. In general, in the case of analog audio cables the shorter the better, if it makes any difference at all.

Also, regarding S/PDIF and AES/EBU digital cables, as you can see in some of the earlier posts in this thread the optimal length is dependent on a great many component and cable dependent variables, some of which are not usually specified (e.g., risetimes and falltimes of the output of the signal source). So 1.5 meters should be considered as having the best odds of being optimal for a digital cable (unless a very short length is practicable, such as 6 or 8 inches), but other lengths may be better in some cases, and there may be some cases where it won’t matter very much if at all.

Regards,
-- Al