Here are the outlets and p-cords.. This is sort of a compromise between using NO Noise Harvesters and using many to reduce the perceived problem of cross-contamination.
From the left:
Bottom (with the gold-colored 'X'), 20-Amp inlet cable, a current-gen. Neotec 10g. with then-best, quite-expensive Furutech ends; top pair, long p-cords to main (Atma-Sphere) poweramps.. These are the new 'JBG Signature' 6X11 cords with AQ NRG1000 ends, now discontinued.*
Center column of outlets, the inexpensive 12g. extention cord supplying the two bassamps (plateamps) for the Super-7s;
Second-right column, shiny-black DH Labs Power+ 12g. cable feeding the Emotiva center-and-surrounds poweramp; and
RH column, current-gen Neotec 11g. cables feeding the 'most-digital' of my components, the Marantz '8805 pre/pro and the Oppo '203 discplayer, and two NHs.. With no NHs plugged in and both the preamp and DP turned on and 'idling', the noise measured at either unused outlet--in fact, at
any unused outlet of the P20--is about 175mV.. Plugging in one NH reduced that noise about 10mV or c. 6%.. Since I'm an if-one-is-good-two-are-better kind of guy, I plugged another NH into the unused outlet.
I also plugged two NHs into the two unused outlets of the above-mentioned extention cord, adjacent to the p-cords of the bassamps.
* The 1000-series cable ends (last RR was $200) have been replaced with the Mistral cable ends, RR $120.