Help me w/my stereo!

[DrtyRat]

I have a pioneer stereo in my car. A while back I got an itch and decided I wanted to put an old punch amp, that I had sitting around, in my car for a little bit of extra sound. I hooked everything up and when I turned it on the speakers were crackling and the music was very low. I decided to take it all out, b/c I figured the amp was bad. So I ran all new speaker wire from the radio to the speakers. When I turned the radio on, there was no sound. The radio display shows everything is operational (antenna, volume, etc..) but I hear nothing, not even static. I decided to call it quits and left it as it was until I had some time to spend on it. When I ran the new speaker wire I connected the speaker wires directly to the stereo's harness. I figured maybe I screwed something up, even though its pretty straight foward.
Yesterday I decided to give it another go. I removed the harness, disconnected the speaker wire from it, resoldered(sp?) it back so that I could use the stock speaker wires again. I reconnected the back speakers to the stock wires, and then turned the radio on....same thing, no sound, display shows everything functional. I'm all out of ideas. This is not something too difficult to do(so I thought). Anyone w/any input on this? What else have I missed?
BTW....
-battery was disconnected
-I checked the little 10a fuse within the radio and its fine
-stock amps have already been taken out
-everything worked fine before the amp was installed.
I'm not a music junkie or anything but I'm tired of not having anything to hear but my exhaust and my odd noises coming from an 14yr old car.