Xor or single ended?

That should read "rca" and "xlr"!!

A phono cartridge is actually an inherently balanced design - it has  a separate hot for left and right, separate grounds for each, and a shield. That makes phono connections ideal for balanced phono preamps, because a truly balanced (differential) phono preamp will have higher gain and lower noise than a single-ended preamp, all other things being equal. Please note that you can have a balanced phono connection using RCA connectors; it's the circuit, not the connectors, that make it balanced.

Thank you Cleeds for a clear and informative answer!

Jake

Dear azjake: cleeds gave you a good answer and the main subject there is:

"""  a truly balanced (differential) phono preamp """

if your phonopreamp is not exactly designed like that hen it does not mattes about how you connect it. Many phono stages comes with rca and xlr input connectors but in reality are not fully differential, so you can get the advantage to lower noise/distortions.
You have to ask on that issue to your phonopreamp manufacturer.

Regards and enjoy the music,
R