Monarch cx40 guitar-bass-keyboard combo amplifier?

hi i have a monarch cx40 guitar amplifier and i need to know if it can be wired to run on a 12v dc car battery? as a mate of mine does busking at the local market and has asked me to get it to work on a battery but how do i do it as there are 3 wires - 2 blue and one gray wire coming from the power supply inside the amp. is it possible the amp is powered by a 12v - and a 12v + rail?|||Do not connect 12 volts DC to the power cord, it will cause smoke. You need a 120 volt AC to 12 volt DC adapter. Ebay has loads of them for sale.