Using cat 8 cables from router to streamer messed up sound

If you have multiple cat8 cables in the system, reduce to one at a time to see if the issue is with one cable.

 

I use UTP cable just to avoid ground loop and that’s the only reason I avoid Shielded Ethernet cable + my streamer came with instruction to use UTP cable anyways

 

Cat 8 is primarily intended for 40 Gb/s over copper, with suitably expensive equipment that supports that. Most home users probably only use 1G, possibly 2.5G connections. Cat8 is not needed for that, and shielding on any category of cable adds potential complication so should only be used when you know it is required.

 

I use CAT 8 for everything, everywhere. No shielding issues - but it's stiff as hell. I upgrade router / mesh often, so I use cable with the headroom for what may be coming.