UK uses 220v 50Hz. US 115v 60Hz. You need a transformer to stepdown the UK's 220v to 115v.
Be sure the wattage of the transformer matches or exceeds that of the unit. (Look at the back of the receiver or the manual for this info) Radio Shack might be a good place to start looking for this transformer as well as PartsExpress.com Good Luck.
While I don't like Bose, I LOVE ripping open the sub in hopes of finding the correct voltage
When we lived in Tasmania, we bought a nice little Jamo subwoofer. We got back the the USA, popped the amp off, played around for a while, and BAM! It worked, new cord end and it was good. On the end of the subs transformer, there were a bunch of wires, and we were able to find the right setup to make it work for 110v.