Getting him in my ARC PH3se phono pre

I use two isolation transformer to hook up all my equipment. 
One has the phono pre, TT motor (VPI Prime) and the speed controller equipment for the TT - 250w.  The other has the preamp, and amp - 1000w. 
I’m getting a hum when I turn up the volume when listing to audio through the TT. Here are the are the conditions it’s happening under:

1. Phono pre must be on for hum to occur. If turned off hum goes away. Obviously, so must amp and preamp Be turned at the same time to hear the hum. 2. Phono pre on, but TT motor off, hum is present. So no music playing. Btw motor is controlled by Eagle and Roadrunner. 3. Phono tubes are new and in good condition. 4. The Phono unit is an older unit, but when I had it connected to another system in another room I did not have a hum problem. 
Not sure where to go from here. Especially since I’m connected to isolation transformers.