If you are forced by circumstances to supply AC from one box to another where it is rectified, you should use shielded twisted pair or two separate coax cables with grounded shields for the power line to avoid radiated emissions. The wire separation forms a loop which has inductance and acts as an antenna. Twisting minimizes the loop area and each twist radiates the opposite polarity of the adjacent one so that radiated magnetic field averages to nearly zero in the far field. Shielding means that the electric field is not seen outside of the cable. You may find that you have no trouble, but you may interfere with other equipment such as wireless microphones (although these are normally UHF) or nearby electrical equipment, or your noise floor comes up a bit.
If the AC is not rectified (e.g. used only for tube heaters) then there is not as much of a problem since with a linear load, no new frequencies are created.