They say a picture's worth 1000 words and since these daily posts are fewer than 100 let's use a couple of pictures to help us understand the difference between our music library played through a computer connected via USB vs. the same connected over a home network. We'll use the Roon server in these diagrams, but the first diagram could use any number of servers, including JRiver, iTunes, Etc .
Here's what a typical computer setup connected to our DAC through USB might look like.
Note a few things here. The big shape labeled "computer" is the hub where the server is and, connected to the computer, everything else. If we're using an iPad or Android tablet we're connected via WiFi through the router, etc. What's important to note is the USB fixed cable to the DAC. USB cables are electrically connected to the power and data lines of the computer - a problem for jitter, ground loops, noise from the computer into the DAC. It is this very connection that products like the USB Regen, Disruptor, Jitterbug exist to clean up.
Here is the same setup only this time, instead of going through USB, we output through Ethernet. This kind of output isn't common for servers and only a few can do it. Roon, JRiver, Minimserver, Twonky, NAS are examples of servers that can prepare their data to be sent over Ethernet.
Note the differences between the two. Ethernet connects very differently than does USB. It is this fundamental difference in the way music is transferred between one machine and the other that makes for the differences we've been talking about these last few days.
