The mains can be very noisy in some areas,with fluctuating voltage and frequency and other gremlins.
it is always wise to fit an anti surge unit as well between your tv equipment and the mains.It isnt rare to find you mains supply howling up to 400 volts taking out almost everything in the house as well.
belkin make the best anti surge units on the market,not the cheapest,but you get what you pay for.
anti surge units come with filters built in but a purpose made filter is the best option to ensure a good clean supply of voltage for your audio visual equipment