Electronic Problems

I went to auto zone and Advance Auto Parts tonight and talked to the guys there about it. The guy at auto zone wasnt much help, but i did borrow their voltometer thingy to test my wiring and sure enough it was getting power. I was stumped at that point why the cd player still wouldnt turn on if the power was working and teh ground was good, so i went to advance auto parts and talked to a guy there that knew what he was talking about. He had me hook up the cd player to the battery to make sure it was good. I told him i had tried it before but he told me to connect the igntion wire and the 12v wires together and then put the ground on. I didnt htink it would make a difference, but the cd player turned on. So i know that its a problem with the constant 12v flow. After a little tinkering i also figured out that the clock and the 12v flow into the battery go together, so i just hooked them both up to the 12v ignition wire for now, and everything is working. So heres my last question: Would i be able to run a regular wire from my positive battery terminal inside the car and have that as my constant 12v flow? Sorry for such a long post! thanks for the help guys