Noisy Cistern

[iddon]

I've just replaced the syphon in a cistern as the diaphragm in the previous one was split and I assumed the trombone pipe vibrating-like noise that it made each flush was as a result of this. Having installed the replacement the noise problem appeared be sorted, however, after 4 days since installation the cistern noise is back again noisier than ever and somehow has also transferred to another cistern as well when it's flushed.
Any clues? Do I need to replace the ball Valve?

 

[seco services]

change the diaphragm in the float valve or fit a new one.

 

[iddon]

Thanks, will pick up a replacement from plumbers merchants tomorrow