i have 4 computer fans at 12v. Im using AC's with 120vAC input and 12vDC output, splicing the red and black wires to the AC. is this the best way to use the power.. ( is the yellow wire needed ?) can i use a larger AC with a 48vDC output to run all four fans ? if its more than 48vDC output... would that fry the fans .. im guessing it would did i guess right? lower volts would just make the fans run weaker correct ? IF SOMEONE COULD CLARIFY I WISH U MUCH KARMA FOR THE HELP> THANKS !