Looks like you just need to feed it 9V.
A 9.6V RC car battery and a home made cable would be easy to make. All of the parts are available at Radio Shack.
IIRC ,it needs 9VAC. AC voltage is hard to get in the field. My guess is the AC is rectified and voltage-doubled inside to get approx +/-15VDC.
I've got an Maudio Duo and it works like that.
By the way, if you're willing to crack it open, I'd like to see the insides. No idea of how good this thing is. It is an economical option for an *installed* setup where you have AC power. That's where i use my Duo now.
Richard