digital S/PDIF cords: quality important

[steelpetals]

I should know this and I know it applies to XLR and other analog cords, but to what degree does the qulity of digital cable play in the signal route. Is it okay to run out of the digital outs of my preamp with a simple rca cable like one uses for their stereo, or do I need something better. Will it affect the overall sound. How about optical cables as well?

 

[Blue Bear Sound]

You should be using 75ohm digital cable for S/PDIF signals, and 110ohm digital cable for AES/EBU signals.

 

[steelpetals]

why is this? Do you get signal degradation if the resistance is different?

 

[Blue Bear Sound]

It's to avoid signal loss (since digital signal contain very high frequencies compared to audio) and to minimize jitter.

 

[Robert D]

Mismatching impedances in a digital transmission line can result in reflections. If you want your data to get there once, and only once, stick with 75 ohm cable. I use Apogee Wide eyed, but I think any 75 ohm cable will work just as well.
RD