Wiring harness question

[Woody182]

I'm picking up my 2004 WRX tomorrow (can't wait!!) and took my stereo out of my current car, I hooked up the old wiring harness to the old CD player and it powers up/antenna and what not but there is not sound whatsoever.
I am pretty good w/ this stuff and can't really come up with a reason why there would be no sound. I didn't have crimp caps so I electrical taped each wire. I just undid each one and resecured them and am positive they are all connected.
What could stop the entire head unit from producing sound?
Thanks in advance