Here are the simple steps to convert from 2 wire AC to 3 wire while keeping the original Hubbell look.
First, should you make the change? It all depends if you want someone to collect on your life insurance. A 3 wire power cord is only a big deal when there is a fault in the device and the ground wire carries the fault current to clear the fault, which is preferred to having the current go through your body or having the current go through audio wires (which probably will get hot, melt, and start a fire).
Left: Original Hubbell HBL7467 two wire flanged receptacle, NEMA ML-1R.
Right, replacement Hubbell HBL7595 three wire flanged receptacle, NEMA ML-2P.
Hubbell HBL7595 three wire flanged receptacle, Grainger 5C798, $16.58.
Hubbell HBL7593 three wire plug, Grainger 6C625, $19.25.
Kobiconn six foot 18 gauge 3 wire grounding AC power cord, Mouser 173-53101, $2.45.
2 - 4700 uF 250V AC line bypass disc ceramic capacitors, Mouser 75-125LD47-R, $.66 each
3 - Number 6 locking solder lugs, Mouser 534-7312, $.14 each.
(Prices are in 2005)