I read in the OCD manual that it can be run at 9 volts or 18 volts. Says that the 18 will make it louder and a few other changes. I can imagine the benefits because I know when I had an EMG loaded guitar and did an 18 volt mod on it, it really opened it up. However my power supply only has one 18v connection and its already in use. How many of you guys use em with 18? For those who have tried both, is it really beneficial at 18? Negligible? Not as good? What did you find? If its really a great change, Ill have to find a way to make it work..Thanks