I'm with GRJ on this. You probably have a suitable DC-output power adapter (wall-wart) lying around...or for a few bucks on eBay...much less $ than an AC-output adapter for the same Watts of power. Most wall-warts have a coax/barrel plug - you can get an adapter (less than $1 on eBay) that converts the barrel/coax plug to screw-terminals so you don't have to cut/splice the wiring.