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

- I'm not using any switching power supply anymore with the dac nor with the streamer. 

- The problem with the phono preamp was there since I bought it, about three months ago. I have tried unplugging everything, even a freezer.

- Plugging in the DAC didn't do anything which basically means if I use a different turntable, it's won't solve the issue. 

- Ferrite cores are on the list, I'll definitely try the 100K grid stopper.

- Yes, I'm using a streamer but it was unplugged of course. Both the DAC and the streamer are powered from Allo Shanti linear PS. 

- Switching the phones off didn't help.

One more important thing to mention is the interference can be also received by the line stage - ARC LS16. I noticed it when I was switching tubes. It only happened when I opened the top mesh though. I'll try again now before I move the preamps to the opposite side of the room. That would confirm the signal is being caught from the air, right? 

- I have tried to bring the phono preamp closer to the wifi router, It doesn't seem to have any effect. I'll try again and share the changes. 

The strength of the signal depends on the height level of the the preamp. The higher I hold it, the stronger it is. I doesn't change above 1,5m/5ft but it changes with every inch closer to the floor below 3ft. 

I think it's the input of the preamp that is sensitive. It's even more sensitive with RCA cables plugged in. It's interesting that even with the input exposed the signal changes when I squeeze the output cables together, still, it never goes off completely. That's basically all I'm sure of right now. 

Thanks for the help, I really appreciate it. 

Agree, that the DAC plugged into the Phono would appear to be like a TT at first glance, however, completely different grounding protocol, and completely different sensitivity to the outside world and interference. 
 

Which EAR-834P model is it?

have you tried eliminating the ground, period.

MP 200 is poly alloy cartridge and in theory is like a moving iron cartridge. I had a similar issue and eliminated the ground and the pulsations and noise went away. This was with a tube phono section from Audio Hungary. Went SS now with SPL.

If it is louder near the floor, could it be the source of interference is in your downstairs neighbor’s apartment? How many floors in your building? 

Another thought, it might be worth investing or borrowing test gear that would allow you to positively identify what type of interference it is. For instance, if @theaudioamp is correct about it being a demodulation, perhaps an oscilloscope trace could prove that. just a thought. 

For Noromance, I would agree with your idea. Just because I recently;y got a new TV (air) antenna that had a built-in filter for WiFi frequencies. IT cleared up a lot of degrading interference. I would also suggest that Philipm looks at his neighborhood to see if anyone has recently added an Illegal CB radio amp or even a HAM operator putting up something new. HAMS are almost ALWAYS agreeable to helping you find a resolution to any interference from their Radio station. EVEN if their equipment abides with the FCC laws. In days gone by the Phono cart itself was one of the biggest offenders acting like an antenna. I also liked the Ferrite rings idea. THat has stopped many offending signals. I have them everywhere and even MY OWN HAM equipment does not get in the way of quality sound from my stereo. If the tinfoil ides had some effect, THat is the first thing I would replace with High-grade shielded Cartridge wires. I really liked the answers here. Not so many people talking stupid or trash, but helpful responses. I will probably get blocked for saying something nice about the site.