Tube PHONO preamp interference - RFI, EMI, bad grounding?

From all the tests you have done, and the results, I believe that your noise is RF interference entering through your inputs and being amplified by the Ear as though it were an audio signal. I suggest getting some shorting plugs (cheap on Amazon) to verify this - just get two of those and connect them at the inputs (not the outputs!). Then listen to the amp. I suspect you will then have no noise at all (which is as it should be). If you have no noise, then that is how the sound is coming to the amp - not through the tubes, or the power, etc. The fact that you do not hear this noise when not in your apartment, and the fact that the noise reduces when you grab the cables makes me think this. 

Some equipment used to come with shorting plugs way back when (my old Luxman R1050 had two phono inputs which came with these as they (shock!) amplified noise from my wifi router when not in use. 

If this experiment has no noise, then not sure what you can do - either get rid of the source generating the RF (hard to do if it is not in your apartment), or perhaps the Ear has an RF filter (ceramic capacitor or an RF choke)  on the input and it has failed. I seem to recall my old NAD preamps had these soldered inside on the inputs for this very purpose. The Ear may not have this at all, but it would be good to pop the lid and check - your Ear may have some kind of input filter and they have failed or their solder joints have failed and they are longer connected to ground? 

@ejb14 

Ok, I'll get them as fast as possible. I actually got this recommendation a while ago but I have been trying so many things I have forgotten. Thank you. 

I have tried to find out how the wifi noise sounds like. Are you able to record it? Is it any similiar to what I have posted? (the noise sample on the top of this thread)

If the stoppers help, I'm thinking the RCA cables would have to be placed in a copper sleeve, maybe even two copper sleeves. I'd solder a grounding cable to the sleeves and ground it to either the phono preamp or to a screw on the ARC linestage. 

(I'm only suggesting this from my previous experiment with an aluminum foil - I had wrapped the input cables in several layers of the foil. The result wasn't perfect but it was ok just to see how the phono stage actually sounds in my setup.)

I'll also borrow some cheap integrated amp and a small speaker. There's a socket on the first floor of my apartment building so I'll test it on the hallway. If it won't pick up the noise then I'll do the same on the top floor. That should give me a hint where it's coming from. 

Just to be sure - sometimes "stopper" will not have a signal pin (like the AudiioQuest stopper is just an RCA cover with no center pin), but for this test you want shorting plugs with the center pin. You want the signal shorted to the ground so there is no signal on the input (which is also why I said don't put them on the outputs - they will blow the amp on the outputs). 

I no longer have the luxman, and not sure if my current preamp is susceptible -(solid state Sutherland PH3D). I will see if I can try something.

@filipm 

I go back to my original statement. Flawed design or broken. It should not due this. If this happens on both channels, then it is a flawed design. A small capacitor between the signal input and signal ground (or case ground) and the noise will probably disappear.  Cables may make a difference .... or not.

Aluminum foil is fine for identifying the source of radiation but if it works you’ll need a more practical long term solution, like possibly tube shields or other.