Power supplies and cables - observations, considerations & commentary

[One and a half]

One of the main design goals of the iFi was to minimize the noise kicked back into the power grid. you shouldn't need a filter.

 

Ifi don't specify what frequencies are transmitted back to the mains. The Ifi wall wart is no angel when it comes to being quiet, if so their aircraft technology should equally work on the AC as well as the output, but there's no mention of this on the Ifi Web pages, so no need to extrapolate into imagination.

[One and a half]

All the more reason to use XLR cables. Leakage currents are lucky to be non-symmetrical.