Ground loop hum

My technics turntable developed a ground loop hum when I got a new preamp Rogue RP7 and power amp Aesthetix Atlas.  I had a ground wire connected to the turntable and grounded it to each, one after the other when the first had no effect. Neither did the second grounding. It has been suggested I ground it to both at the same time which I haven’t tried yet. Any other suggestions?  I am running the system from two dedicated 20 amp lines. Running Vandersteen Quatro wood ct speakers.  Thanks in advance.