Look into a universal ac adapter: Amazon.com: Universal AC Adapter 15V 16V 18V 18.5V 19V 19.5V 20V 22V 24V 70W: Computers & Accessories
This will give you the ability to lower the incoming voltage and reduce the flow without having to replace your powerhead. These are also cheaper then getting a new one shipping from Hong Kong when yours breaks as I have gone through both of the originals they sent me (not quite sure why).
^solution^