Sparton 5348CC Tube Radio Help

[The Senate]

Hi, first time EEVblog poster.

I recently acquired a Sparton 5348CC tube radio from the 40's. I am looking to "enhance" it with bluetooth, but preserve as much of it as possible, so I'd rather not rip it apart to add an aux input. I'm planning on replacing all the wax caps and resistors. From what I've read, the Mica caps should still be fine so I'll test them and replace them if needed. The radio has an RCA phono input jack, so I was thinking that I could get a bluetooth receiver to RCA output adapter. However, according to the schematics (which I've included) the RCA signal return line is connected to the hot chassis. I assume that this would interfere with the adapter, if not destroy it. Does anyone have any ideas on how I could go about doing this?

[PA0PBZ]

It's got a proper mains transformer (T4) so the chassis is not hot.