Replacing the stock 2 conductor power cable on my Nakamichi 582 cassette deck?

I am thinking of replacing the stock 2 conductor power cord that came hard wired on my Nakamichi 582 cassette deck.
So here is my question.
Should I just replace with a much heavier gauge of cable and leave in the 2 conductor non grounded as OEM supplied configuration.
or should I replace with a 3 conductor and add a ground and if so where would be best to add it at the cassette deck end? Or would that be a move that may actually induce some type of ground loop/hum?
Thank you and Merry Christmas!