Peculiar Hum Issue on Jolida JD9 Phono Preamp

I am experiencing hum in my phono preamp after upgrading several of the internal components. The rest of my analog equipment is Teres TT, Basis Vector 4 arm, Zyx Airy 3S SB cartridge, Linar Model 10 amp. I first noticed the hum after one set of upgrades whenever I connected the arm cable to the Jolida. I reduced it to manageable levels by changing the 12AX7 tubes in the preamp to 12AU7 variants (to reduce gain) and using a lower gain setting in the Jolida.
More recently, I upgraded caps in the input section and I purchased the Granite Audio phono burn-in CD. I connected the output of my Oppo 83SE player to the Jolida and now the hum is back. I used 12AX7 tubes for the purposes of burn in as I don't want to reduce the life of my 12AU7s.
If the RCA cables are disconnected from the CD player but still connected to the Jolida, there is no hum. The Oppo does not have a ground in the AC connector.
I know I can probably get the hum down to manageable levels again when I switch to 12AU7 tubes but I would like to try to eliminate this altogether. Any suggestions as to what I can try?
Should pair it up with my Jolida amp which hums loud enough to be a spare air-raid alert. Junk.
I disconnected the HDMI cable from the OPPO player and the hum just about disappeared. I had not thought of the TV as a contributor to this issue. How can I eliminate the ground loop while keeping the HDMI cable connected? Would I have to connect the TV's AC cable to a separate circuit?
It might not be the TV. Your last experiment just gives us a direction to look into.

We need to be sure it is the TV chassis. Try hooking up the Oppo's HDMI but disconnect any other sources going into the TV. If the hum is present only when the Oppo's HDMI is hooked up than I'd try isolating the ground pin on the TV's A/C cord. If it does not hum with just the HDMI from the Oppo than hook up your other video sources one at a time until you find the culprit.
Thanks Jjrenman. The problem is definitely the TV. I'll work on isolating the ground pin on the TV cord.