08-12-12: JeffatusI'm hesitant to contradict Al's opinion, since he's eminently qualified in these kinds of technical matters, while I am not.
I have my computer hard drive connected to the router via cat6 cable, non shielded. That run is about 10 feet. Then I have a 50 foot run, cat6 unshielded, from the router to the DAC.
It sounds like a relatively inexpensive experiment to try the shielded runs, but what about the router? I just keep thinking about all of the money I have spent for high end gear and their fancy connectors, etc. and want to know if a $120 router will be my weak link.
Having said that, I suspect it's possible that your router is degrading SQ. I would consider two experiments...
1. Replace your unshielded Cat 6 with either shielded Cat 6 or Cat 7 (always shielded by specification). Cost = about $25.
2. Remove your router from the system, run a direct ethernet line (preferably shielded) between your computer and your dac, and see if it sounds better. If it does, but you need the router for functionality, you can either...
(a) use the router wirelessly, so that there is no hard line between it and the computer, or...
(b) add a simple ethernet switch downstream from your router. So the arrangement would be...
computer -> 1' Cat 6/7 to ethernet switch...
...ethernet switch -> 10' Cat 6/7 to router
...ethernet switch -> 60' Cat 6/7 to dac
If you added all new cables and an ethernet switch, cost = around $65.
As I mentioned above, I experienecd significant improvements in SQ when I went from unshielded Cat 5 to shielded Cat 6 and then more improvements going from Cat 6 to Cat 7.
As for the router, in my current arrangement, I have two ethernet switches in the configuration, so that when I listen to music, I can kill the power (with a simple rocker switch) to the ethernet switch closest to the router, which severs the hard line between the router and the audio system.
You may just wonder why I don't just shut off the router. The reason is that I don't want to interrupt the other wireless devices in the house from communicating with it, and I don't want to wait for a long reboot when it turns back on. With the ethernet "kill switch," the reboot is about 5 seconds and there are no settings to be lost/changed, so it's idiotproof. Good thing for me.
Bryon