another thought, would polarization even make a difference? either side of the line is at +120v or -120v (+170v, - 170v peak) depending on what part of the ac cycle is happening.
Of course, it absolutely would make a difference. First, you need to understand electricity and how AC is delivered to your home. If your equipment was connected to 240V, and the neutral was not connected, your unit would be connected to TWO hot leads. So regardless of which lead you touch, you are fried extra crispy. But your unit is NOT connected to 240v (is it?), but 120 and on 120V, your set is only connected to ONE hot lead. The other lead is a neutral wire, which is actually bonded to ground (earth) at the main panel. In other words, the neutral wire and ground wire will be on almost equal potential. I say "almost" equal because there is some miniscule resistance at every connection, and therefore, the potentials might vary by some miniscule amount, but if everything is properly connected, then the difference is negligible for all practical purposes. Effectively, this means that if you were to accidentally touch the hot lead of a 2-wire AC cord, you are fried and likely kaput. But if you were to accidentally touch the other neutral lead of a 2-wire AC cord, then you are actually touching ground. While you are into testing, why don't you do this: Insert one meter probe into the round ground hole of your AC outlet. Then insert the other meter probe into one of the flat blade slots, then the other slot. You will notice 120v potential from one of the slots, and 0v or some other small number from the other slot. Remember, that the secondary of your boombox is tied to "one" of those AC receptacle slots through that 2.2 mΩ resistor. So does it make a difference which way the plug is plugged into the outlet? YES. You make it sound like when the AC swings from the +/- parts of the cycle, that the "hot" leads will reverse. It does not. While the electricity does indeed flow the opposite direction, the neutral lead will always be neutral and not "hot".