That’s a challenge, for sure.
Never heard any “noise” like that coming from my phono stage, or any other component for that matter.
Sounds like a radio that is trying to pick up a signal, that won’t tune.
And the beeps are odd.
As others have said, sounds like WiFi/router signal.
And as you’ve taken it elsewhere, and it works perfectly, it’s likely not a defective phono stage. Adding the TT increases the noise, which makes sense as the cartridge will also pu the interference.
Have you tried plugging another source, other than a TT, into the phono stage? Like your DAC (powered up, but with no signal/source of course…)
Just curious if that removes it.
Sorry for your headache, must feel like you’re chasing a ghost…
The EAR-834P box is a pretty solid brick of metal, which should help to shield the tubes from the interference?
Something is the source of that noise, I know you prefer to shield the gear, but hunting down the source might be an easier task.