When I flush the toilet in the master bath is makes a whining sound in the pipe. It does not make that when I flush the other toilets in the house. This is a new sound.

If the toilet is older, it is most likely the fill valve diaphram. Replace the whole fill valve with a new one.

Not so fast with the replacement. Let's see if there's a simple repair. Which ballcock is yours? (see image) Back to you. Tom

We're getting a low vibration hum - our ballcock is the one on the right. Can you advise?
Thanks
Tommy

You can reduce the noise by turning the angle stop until the noise stops or you can shut the water off and unscrew the top three screws and pulling the ball and stem assembly up and away. Now pry out the washer , turn it over and seat it back firmly. Before you reassemble turn the water for a second to flush out the supply. Reassemjble and test. Good luck. Tom