Add three prong power cord on Yamaha M-80?

[AudioNoob57]

I recently bought a "refurbished" Yamaha M-80 amp but its power cord is a spindly, 35-year old thing and its input contacts are so worn they look like they're made of wood. I'm thinking of adding a IEC power socket so I can take advantage of third party cords. The thing is, it has a separate ground contact that causes a hum when I ground it.

Shouldn't this amp need a ground? I've had a lightning strike recently that killed all my equipment and I'd like to protect against this in the future. So does adding a power socket for a three-pronged plug make sense?

 

[Verdinut]

I recently bought a "refurbished" Yamaha M-80 amp but its power cord is a spindly, 35-year old thing and its input contacts are so worn they look like they're made of wood. I'm thinking of adding a IEC power socket so I can take advantage of third party cords. The thing is, it has a separate ground contact that causes a hum when I ground it.

Shouldn't this amp need a ground? I've had a lightning strike recently that killed all my equipment and I'd like to protect against this in the future. So does adding a power socket for a three-pronged plug make sense?

It was released with a two prong plug so it doesn't need to be grounded. But should you replace the plug, if it has one of the plugs wider than the other one, then you have to get the same type of plug and make sure that you keep the same polarity, if you don't want to risk electrocution or damage to other equipment connected to it.