Panasonic cordless phone kx tg3031b

Hi there, wondering if you could shed some light. I have the above cordless phone. It was supplied without a power adapter so i purchased the appropriate adpater. The base unit required a 9V 500mA. Purchased

The unit works fine apart from there is an annoying clickingsound and line noise. The phone line has been checked out ok. One other point is that it is a US model and i am using it in New ZEaland. Is there any major conflict?

Thanks for your help