I can’t imagine (but I don’t KNOW) that an NH’s capacity would be exceeded by much of any kind of noise, and that 10KHz signal may not even be in the frequency range the NH eliminates… But even if either is true, the digital trash created by the components we have plugged into a p-con’s outlets(1) still gets into all the other components plugged into that zone or outlet… That’s why I’m concerned with isolating or removing that noise… In a, say, P20, I’d have an NH plugged into each zone, just as I’ll have NHs plugged into EACH outlet (that’s feeding a component) of my BPT 3.5-Ultra Imp. balanced-power p-con.
Maybe Paul will opine for all our benefits. … 
(1) unless EACH outlet is filtered both inductively and capacitively as they are in audience’s larger p-cons.