firstly... don't dc bricks usually have their own power transformer and cable... and second... i wouldn't think it would use an 18 volt input for the dc brick...

does the input to your dc brick require 18 volts?
Faded Gibson SG Special - Black ice mod
Seymour Duncan SH-5 in bridge
B-52 AT 112
Ted Weber Mass100 attenuator
EHX Small Clone
EHX Metal Muff
DIY Modded tubescreamer
Dunlop 535Q Wah
Wax Potting tutorial