Are my CAT5 and router my weak link?

???=less digital cable and system noise since they both produce jitter. Also less analog cables pickup. One thing to remember is that speed of Ethernet cable directly doesn't effect anything since data has no timing. Effect is indirect by radiating noise.

Jeffatus, Time jitter is the only thing that affects sound of digital transmission. Wireless or Ethernet data is just that - a data. It means it is being sent in packets without timing. Bad Ethernet cable or wireless router can cause disruption is data delivery resulting in dropouts but cannot change the sound.

If I understand it correctly Ethernet cable connects computer to wireless router. If that's the case then it is in some distance from the DAC that has built in wireless receiver eliminating capacitive coupling and leaving electromagnetic radiation to consider. This radiation is practically eliminated, not only by very tight (>2twists/cm) twist on CAT6 cable, but also the fact that signal is balanced. Radiation is limited to common mode noise coming from the system (perhaps power supplies). This noise (whatever the source is) has to be strong and at least 30MHz to make effective (1/10 wave) receiving antenna of typical 1m interconnect. At this frequency skin effect is very strong and interconnect's shield is working very well (Noise from crude computer switchers is in the frequency approx. 100kHz and has no chance to be received by 1m antenna). Of course it would be wise to keep this Ethernet CAT6 cable as short as possible and far from the DAC.

Bryon, Your case might be different. Perhaps Ethernet cable was in close proximity to analog wiring (interconnect or speaker) or I'm just plain wrong about it (I was wrong once in 1960). Audio is not exact science and I'm just trying to understand. Maybe balanced drivers are never exactly symmetrical and there is some high frequency component. It is possible that computer you used produced high frequency common mode noise. I hope Al will help with this.

Mapman, I Agree 100%. Not only that computers are noisy but also can and should serve its main function and therefore its location might be remote (mine is across the room). I use my computer during music playback because I know that it cannot change timing on the DAC side. For the same reason I use free Itunes, cheap computer, not a lot of memory, standard external hard disk etc. SIMPLICITY.

Al, Thank you. I often tend to think in absolute terms while boundaries in reality are not that sharp. Tubeking sugested that shielding might compromise twist density making it worse instead of better. It is easy enough to compare since Ethernet cables are not expensive. I would use shortest possible cable as far as possible (since field drops rapidly (inverse square) with the distance. I would also avoid setting router at full power in close proximity if there is no need for that (no dropouts).

Do shielded cables require special connectors? I thought that plug has 8 pins (4 twisted pairs) with no room for the ground. Ground would have to somehow clip to chassis.