Mercury PT Wire Question

[heymymy]

Hi, I'm new here...  I have a tone clone Mercury Magnetics 5f6a PT here and I'm using for a scratch build Bassman.
My question is, on the schematic for the PT the two black wires one says 0v and one says 120v, I've never seen this before
on a schematic, so what I'm asking is, does it matter which is which?  On the Hoffman 5f6a layout it says there should be a white and a black wire, are they interchangeable, and if not, how do I measure which is which.

Thanks everybody!

[sluckey]

It doesn't matter. Just pretend that one of your black wires is white.

[heymymy]

awesome, thank you!