Getting him in my ARC PH3se phono pre

I found some 8 foot rca’s and pulled the TT to the middle of the room. The hum was the same. 

 Not sure it’s the cartridge honestly. The hum does not increase or decrease when you move the arm towards the spindle. It hums even with the the arm just sitting In the cradle and the motor isn’t even turned on.  In fact the hum is constant and whether or not you touch the cartridge, or move the wires, or anything like that, it doesn’t change the hum. 
The only thing that has changed it is when I took a power cord and plugged the stereo in from across the house In another outlet.  The hum was greatly reduced. Almost to the point I’m not being an issue at all. That tells me it might have something to do with dirty power or something similar.
But I cannot rule out the cartridge 100%. Because if I just unplug the interconnect cables from the phono preamp I get no hum whatsoever.   It’s only when the interconnects are connected from the turntable to the phono preamp does the hum present itself. 

Ok. I tried all Components from the same outlet to no avail. Still got the hum. 
However i think I’ve determined it’s tied to the cartridge - I think. 
It’s a brand new Grado Sonata 3 - Timbre series. Couple things - I know Grado’s are known for their “hum”, but in this case I get hum when there is no record playing and the motor is off and the tone arm is at rest - rest of the system is on. If I unplug the IC from the TT to the phono pre the hum stops.

there is no change in hum when the record is playing, needle up or needle down, close or further away from the spindle. 
I’ve also moved the TT around and away from the phono pre to no avail.  I was only able to move the TT about 2 feet away from phono pre, amp, and preamp, so I’m not sure that’s far enough. 
i tried laying tin foil over the cart to see if it would shield it, but it did not. Though I’m not sure that’s an effective way to test. 
This cart’s output is 1mv where my previous was 2.5mv, so I don’t really know if it’s this cart specifically or the all carts since I have to turn it up much louder to get to the same dB level. But my gut says it did.  

Not sure if there is a “fix” for this, but I REALLY like this cart so I’d hate to send it back. It only hum audibly at a bit over halfway up, which men’s i only really her it in the quite sections. 

I have done the ground wires to no avail. In fact I have run a ground wire from all the components and tried all kinds of combos. Nothing changes the hum.

i have a Hum X cheater plug and that did nothing either. 

The turntable is two feet away from the other gear. 
I don’t know if this means anything but on the opposite side of the wall the TT is located is the kitchen, and more specifically the oven/range. It’s a gas range but modern so all electronically controlled. Anything could emit from that?

also what I don’t get, is I could have nothing but the table and the cart attached to the arm, no motor, no motor even installed, and I get the hum. 
The Phono unit is dead silent until I connect the tone arm dongle to the VPI “box” the rca’s are in. That what makes me think it’s the cart, I just don’t know what it’s picking up. 

I can run all the electronics through a 1000w isolation transformer and I can lift the ground to the transformer and I still get the hum with no noticeable hum reduction.  I thought isolation transformers were supposed to eliminate ground issues. 

However, I ran a 50’ power cord from across the house to another outlet and it reduced the hum at least 50%. So it appears the house electricity is causing the issue in some  circuits. 

I did a bit of research in the RAM tubes and ordered the set. 
Yes the PH3se is a great phono and a keeper for me. I don’t know what it’s equal is today but it does sound great. 

Ok guys. I’ve been sheltered up for the last day due to Laura - I’m about an hour and a half away Lake Charles. 
I’m very lucky after the last week, puts my problems of humming in perspective for sure. 

I will look into the latest suggestions once I uncover all the equipment and plug everything back in. 

Ok. Update. 
It’s not the TT, cart, stand, motor, and it’s not the phono preamp (since I changed phono pre and it still did it).

i just hooked up a different TT with a different cart set on the concrete floor, and ran it to the same preamp / amp and I’m STILL getting the pumping. 
So it must have something to do with the amp or preamp. 
They are both tube components, so what could be happening here? They are both old in the tooth, but what’s odd is they don’t do it with the CD player, just when the TT.

The directly above post should have gone to my other post. 
Please disregard