yea you can if the power supply has -12v, you hook the +12 and the -12v lines and you have 24 volt.
So it's like you replace the ground with -12v, i use this to run my comair rotron so i have the red wire hooked to +12v and the black(ground) wire hooked to the -12v.
Make sure you check the max watts on the -12v line because it's usually pretty low like 6 watts.