A $9 volt meter will easily tell you, and could be useful for other things in the future.

But you might look to see if the shell has a lock screw holding it in place, or itself screws loose from the plug (my balanced cables from Bluejeans are TRS).

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris