We recently had a new substation installed in the village and a lot of the overhead cables updated/replaced. since then i have noticed that the power supply for my pre-amp has become noisy and replaced quite a few light bulbs. I didn't think about the mains voltage until i recently bought a headphone amp and it was humming like a b......d. I contacted the manufacturer of the headphone amplifier who after some debate suggested that i had my mains voltage checked by a fully qualified electrician which i did. It was discovered that my mains voltage is running at 247 volts which is getting on towards the top end of the recommended voltage. I contacted the appropriate agency to discuss the matter and was told that it was in the range and therefore nothing could be done to lower the voltage by them to my property. With this in mind i contacted the electrician who informed me that the only thing he could suggest was wiring in an Optimisier on my distribution board in the garage. This would cost about £500 which is a lot of money. Any suggestions chaps?