Ethernet Cables, do they make a difference?

The ethernet cables send 1's and 0's (high or low voltage) only. They do so at about 0.8 times the speed of light. If your digital devices sends the message, 0011010110, and the digital receiver reads those numbers intact, it doesn't matter in any way what cable transmitted it.

The ethernet standard is to have no more than 1 faulty bit in 10,000,000,00 (1 part in 10^10). If the fidelity were not this high computer networks would be basically useless. Computers do not tolerate data errors. The ethernet protocol essentially guarantees complete data fidelity, If a data packet is misread, it is sent again until it is correct. With the error rate spec'd above, this would mean about one re-sent data point every hour, assuming 96 bit data depth and 40 kHz sampling (which is well beyond anything in the audio industry). The digital error rates in recording are many times higher, by the way.

In short answer, it is simply not physically possible for your ethernet cables to make a difference in sound quality.

The easiest way I can explain it is with this analogy: 

You order a CD and it comes to your house packaged in a cardboard box, you open the package and play the CD on you CDP. If the same CD was sent to your house in a nice metal box with gold flaked paint on it would the CD inside sound any different? No, of course not.

“it is simply not physically possible for your ethernet cables to make a difference in sound quality”

“If the same CD was sent to your house in a nice metal box with gold flaked paint on it would the CD inside sound any different? No, of course not”

Easily the most absurd claim and analogy so far....LMAO😄😆😂

The correct analogy is that the 1s and 0s argument is the same phoney baloney argument we got regarding the so-called perfection of the CD. I.e., “perfect sound forever.”

Another correct analogy is that the 1s and 0s argument fails for Ethernet cables for the same reason it fails for the Digital cable for an external DAC.

Finally, regarding the potential effects of RF noise on analog circuitry, the sonic character of whatever audible consequences may result from effects such as intermodulation of that noise with the audio signal, and demodulation of AM (amplitude modulation) spectral components of the noise, it seems to me could very well manifest themselves in either or both of the two categories you defined.

CAT5E UTP cabling has good noise rejection up to 30MHz and this is quoted from "The Antenna Myth" by Siemon:

The Antenna Myth

It is a common myth that screens and shields can behave as antennas because they are long lengths of metal. The fear is that screens and shields can "attract" signals that are in the environment or radiate signals that appear on the twisted-pairs. The fact is that both screens and shields and the copper balanced twisted-pairs in a UTP cable will behave as an antenna to some degree. The difference is that, as demonstrated by the simplified loop antenna model, the noise that couples onto the screen or shield is actually 100 to 1,000 times smaller in magnitude than the noise that is coupled onto an unshielded twisted-pair in the same environment. This is due to the internal pairs’ well-defined and controlled common mode impedance to the ground plane that is provided by the screen/shield. Following is an analysis of the two types of signal disturbers that can affect the noise immunity performance of balanced twisted-pair cabling: those below 30 MHz and those above 30 MHz.

At frequencies below 30 MHz, noise currents from the environment can penetrate the screen/shield and affect the twisted-pairs. However, the simplified loop antenna model shows that the magnitude of these signals is substantially smaller (and mostly attenuated due to the absorption loss of the aluminum foil), meaning that unshielded twisted-pairs in the same environment are actually subjected to much a higher electric field strength.

The good news is that the balance performance of the cable itself is sufficient up to 30 MHz to ensure minimum susceptibility to disturbance from these noise sources regardless of the presence of an overall screen/shield

Also WRT to jitter. Everytime some one brings up jitter and asynch Ethernet and the DAC output you can safely place them in the "They have no idea what they are talking about" bin.