[W9TR]

Originally Posted by Still-One

I copied this from a response I read. I think this sums it nicely.

The claim here is not that the digital bits on the cable (via the Ethernet frames -> IP frames -> TCP packets) are being altered. The claim, especially in regards to ground loops, is that the ethernet cable is connecting the ground of power going into the switch and the ground of the power going into the device. Thus, you have a system that has “2 grounds”. It is then further claimed that these ground loops, using the hardware given, produce a notable hum or degradation of quality in the D->A conversion, or even later in the chain in analog.

Jim,

This could be true, and it makes sense, but unfortunately it is not true. It was written by someone who does not understand how Ethernet works. So it is, for lack of a better word, bullshit.

The quoted post was 1/2 right - there are logical ways Ethernet components can impact the sound, but ground loops are not one of them.

The IEEE spec for the Ethernet cable to device physical interface calls for transformer isolating the Ethernet cable from the device internal grounds. Each of the 4 twisted pairs in an Ethernet cable is transformer isolated, differential, and floating. Just like the balanced audio interfaces we know and love.

So there are no ground loops in Ethernet cables by definition, unless those cables do not meet the Ethernet spec.

There ARE ways that Ethernet switches, cables, and devices can make an audible difference in what we hear. There are opportunities for EMI, RFI, and noise to travel across Ethernet cables and get injected into the electronics they are connected to via the surge and lightning protection components that are an integral part of the Ethernet spec. The transformers themselves also have inter-winding capacitance that will couple noise into the associated electronics. This EMI, RFI and noise will have an unpredictable impact on the attached audio gear.

There are a number of companies claiming to solve or mitigate these issues with purpose built cables and switches. They are on to something, as are the audiophiles who hear a difference between different switches and cables.

I would never say that Ethernet cables and switches can not make a difference in the sound we hear, because there are very valid reasons that they can make a difference.

Tom