Low Voltage problem What type PLC use?

Hi,

I am living in Hong Kong where it's 220V. However, my house only got 208V. The soundstage from my hifi collapse and it lacks of power and focus all the time.

Pls kindly advise what type of power line product should be used to solve this problem? A power plant, isolated transformer, or power line conditioner?

Thanks a lot.
Eric