Jeff, you've got it right, except that it would probably be a good idea to upgrade the router-to-switch cable, in addition to the others. Although that cable will no longer be in the signal path between the computer and DAC, it could still conceivably radiate or couple digital noise into pathways that ultimately lead to the DAC, or even to other parts of the system.
Considering the low cost that is involved, Bryon's suggestion of the switch seems worth trying, although whether or not it will make a difference for the better is anyone's guess. Among many other things, it would depend on how the characteristics of digital noise generated by the switch may differ from the characteristics of noise generated by the router; on the degree to which router-generated noise can propagate through the switch; how the risetimes and falltimes of the output signals of the router and of the switch compare; and on the sensitivity of the DAC to all of these things, if indeed it has any sensitivity to them at all.
Regards,
-- Al
Considering the low cost that is involved, Bryon's suggestion of the switch seems worth trying, although whether or not it will make a difference for the better is anyone's guess. Among many other things, it would depend on how the characteristics of digital noise generated by the switch may differ from the characteristics of noise generated by the router; on the degree to which router-generated noise can propagate through the switch; how the risetimes and falltimes of the output signals of the router and of the switch compare; and on the sensitivity of the DAC to all of these things, if indeed it has any sensitivity to them at all.
Regards,
-- Al

