Got my Variax Standard yesterday.
Variax models are quiet but I experienced the magnetic pick up noise, with or without the battery installed. I will have to move around within my music room to find a 'sweet spot' with lesser noise.
Later I discovered the culprit of this noise was the fluorescent bulbs of my room. The magnetic pick ups are quiet when i play without switching on those fluorescent bulbs. I will be replacing them with LED bulbs and see if it helps. Ceiling fan contributes very minor noise in my case.
You will have to experience yourself to first switch on all electrical / electronics appliances in your room (or wherever you play your guitar), switch off 1 appliance at a time until you found the culprit.
Good luck!