noise from cold water feed pipe into header tank?

when I open the hot water tap (any one in the house) after a few moments there is a very loud vibration through the cold water pipe as the ball valve in the header tank starts to deliver water in to re-fill the tank,I have had the washers replaced in the valve unit and have had a plumber just fit to-day an air cushion pipe to the pipework at the tank but still the problem exists. Please can you help ?

J.R. Mac
August 2009