inline heater very loud- normal?

[Nano]

Anyone using hydor inline heaters? If so have you noticed any noise like a loud long annoying buzz that comes from it when it kicks on and can be heard from outside the house. I'm guessing this isnt normal so i've shut it off and tossed in a ebo for now. Any way to fix this? Its sitting upright as it should& is plumbed correctly. Did I get a bumb heater? Or is this just a price I pay for having an inline?

Any help is appreciated- if you have a suggestion for either a better inline or stealthy in tank heater please let me know.

Thanks everyone