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

If the transformer itself is humming, try tightening down on the screws that hold it to the chassis, and on the screws that hold the laminations together. Sometimes the case of the transformer can be a little bit loose and this can allow the laminations to vibrate and produce a hum. Transformers by their nature do not transmit DC, but DC can cause the transformer to be noisy. Make sure the transformer laminations are tight and that the transformer itself is firmly affixed to the chassis, and then report back whether that did any good as regards this latest problem. Of course I do not expect this to cure your problem with RFI. 

This is definitely a fascinating post (at least for me), with so much detail explored. The greatest thing that was accomplished right off the bat was the fact that the OP (filipm) was able to record and post the noise or interference that he is experiencing and hearing. When trying to troubleshoot noise and interference, *that* is worth gold all by itself. With so many suggestions already being offered and tried, I'm not sure I have anything left in my arsenal to propose. I'm going to go back over all of the tips and suggestions, and see if I can offer anything. This is definitely one of the worst cases of noise (RFI & EMI) that I've ever heard. So far, it looks like finding a fix for this particular setup is quite the challenge. I completely understand your frustration filipm, but admire your tenacity.  

>>>very late at night or very early morning, do you still have this noise? If not, then I’d suspect someone in your building is the culprit.<<<

I was just wondering if this question was ever answered? Is the noise consistent at all times of day or night?

Do you have any other phono cartridge (already mounted in a headshell) besides your Nagaoka MP200? If you do, does the noise change (in any way) when using a different phono cartridge?

As an A-B test, is there any noise difference when completely bypassing the EAR (pretending for a moment it doesn't even exist), and feeding the turntable (TT) directly into the ARC LS16 mk1 TT input (I realize the Bryston B60 does not have a TT input)? If the noise still exists, does it still exist when trying a different set of RCA cables (feeding the ARC LS16 mk1) ? I apologize if these questions/suggestions have already been put forth.

@lewm I have done that. A quarter of a turn for each transformer to be fully tied up. I could probably do a little more but I'd have to push it hard. I'm already ok with spending something extra for a service, I just hope they won't suggest anything crazy like changing all the tubes and a transformer. They also said how important it is to have matched pairs and that you won't really find them on regular online tube stores. I have found a very similiar thread also with a REF150 (non SE version), contacted the OP and I think there will be more to it than the screws. I also talked to a guy who builds tube amps and he told me I should have replaced all the tubes right a way as a prevention. Well, I think it will get resolved sooner the EAR preamp issue anyways. 

@dpop Well, I used to have an Onkyo A7 integrated with a decent phono stage, Tesla ARS840 speakers and Tesla NC450 turntable (all for about $700). Good times, no problems (just horrible acoustics) and lots of listening time with friends. :) 

Now I have built some amazing acoustic panels and clouds, hanged curtains and I'm left with a streamer, chord qutest dac and a solid state power amp. Thanks god the LS16 is working!

I have tried: different power cords, RCA interconnects, powering the EAR from a battery, pairing it with different components, changing its physical location within the room, placing it into a baking pot, shorting plugs (I think that proves it's not the turntable or cartridge issue), running a ground wire into a socket ground pin, ground wire to a apartment heating unit., lifting the ground on the EAR's power cord, turning off everything in the apartment except the audio stage. I even had my neighbors wifi routers unplugged for half a day, different times - late night, early morning.. nothing changed.

what worked: taking the EAR somewhere else, friends' places etc. (sounds lovely), covering the unit along with all the interconnects into a baking pot placed on the floor (as pictured before), holding the output interconnects with both hands (grouding it).

what I would like to try: few floors lower - same building, plugging it in in a friend's aparment in the next building, a power plant, different set of 12ax7 tubes, some kind of a filter, tube shields.

My electrician says it could be some kind of a server station near by, or a bitcoin mine. He's coming back soon to measure the grounding properly along with the DC presence. 

But really, if it was coming from the AC line, the battery would have solved it. But if it's coming from the air, how come the shorting plugs didn't work? (The result with the battery was the same noise + strong ground loop. The shorting plugs just acted as antennas, just like a regular RCA cable. And yes, I have made them properly and tested them with a DMM.)