Are my CAT5 and router my weak link?

Eniac,
Did you notice any difference in SQ?
If so what?

Hello Al, thanks for your response. The only detail I could dig up about this devices ability to reject current leakage across the optical isolation barrier was found in an article pertaining to the European Medical Device Directive (EN6060-1) which this product is said to comply with.

If your real bored and feel like reading it I have linked to the document below which talks about the allowable current leakage given a certain air gap distance which I can only assume this device complies with. From what I saw, the European standard allows for .5mA worth of Earth leakage & a .1mA enclosure leakage under normal conditions. Double that during an "Event".

Article can be found here:
http://www.newark.com/pdfs/techarticles/xpPower/MedicalPowerSupplies.pdf

SGR, In terms of the SQ differences I heard before and after the installation of the device I'm afraid that in my setup I heard no change under normal day to day listening.

I think I could here a slight difference under critical listening sessions (more air around the performers within the soundstage) but certainly not enough to convince any DBT subject.

Please keep in mind that in my setup previously described I have already gone to great lengths to minimize the propagation of noise via the LAN cables as much as possible even before the purchase of this device. In someone else's system the SQ differences may be far greater than my own if they haven't taken all the same precautions. One example of these precautions would be that I maintain at least a 3ft gap of separation between all of my various networking equipment and non of which share the same electrical outlet. This alone helps with any one noisy device from polluting the other which could ultimately compound the amount noise radiating thru or traversing down the Ethernet conductors toward your audio system.

Eniac, thanks for providing the link, which I read through. It doesn't seem particularly relevant, though, as what it is addressing is leakage current that occurs in response to the AC line voltage, at the AC line frequency. The concern here, of course, being mainly digital noise at very high frequencies. Also, since this device does not utilize any AC power, I suspect that its qualification against the EMDD is pretty much a formality, at least with respect to leakage considerations. Finally, I note the statement that:

Reducing leakage current within a power supply usually means eliminating or limiting the value of Class Y filter capacitors from live-to-earth and neutral-to-earth. It also demands that stray capacitance to earth is minimised through careful design. Unfortunately, the overall effect of these measures tends to compromise EMC performance, although minimising stray capacitance can reduce common mode noise.

So in the kinds of designs being discussed in the paper there can be a tradeoff between minimization of AC leakage and optimization of EMC (Electro-Magnetic Compatibility, referring to the effects of radiated interference).

That said, as I indicated earlier the device does seem like something that can be beneficial in some systems, and that has no apparent downside apart from cost. Thanks again.

Regards,
-- Al