Recommendation for Digital Coax

Typically optical is of inferior quality. Generally known, I tried it a couple times and had to agree. I think it is the transducers that change from electrical to optical and back. I doubt any audio companies could make their own and probably are a commodity item not made as quality above cost.

Why not optical?

plenty of reasons, the search bar above is your friend

Well, I decided to try the cable recommended by soix. Always go with 1.5 M.

Transparent Cable is a good option 

Big +1 @ghdprentice that optical adds two additional and unnecessary conversions .

@mesch good choice and think you’ll be pleased. Make sure you pay attention to the directional arrows, which on my cable are faint and hard to see. I inadvertently installed it backwards once and my system literally sounded broken until I figured out my mistake. Ugh.  Please report back with your impressions if you would.