NETGEAR Powerline Adapter 2000 Mbps

Forced to bring my internet connection upstairs via this contraption to enable my music server to access metadata and function.  No, I cannot do it wirelessly.  

At first I thought I had witnessed nothing short of Black Magic as the signal works flawlessly with the server.  Then the reality of a 60Hz unslayable entity entered the realm.  I’m temporarally running Quad 12L active monitors.  Unplugging one monitor kills the hum completely in the remainig monitor.  Quads are on the same wall circuit as the Netgear.  Any ideas on how to slay the beast would be appreciated.  Thanks
Can you reverse the situation-unplug the other speaker and see if the hum is gone?
It sounds like one speaker may have a ground fault.