Audio Systems: car stereo and speakers DC power, computer power supply, dc power supply

Question
I have a Sony XR-7077 FM/AM Cassette Car stereo that i want to turn into a workshop radio/stereo. Also four speakers that i want use. I also have the installation/connections and operation manuals. Recently tried to power it up with 12V DC at 8 amps from a computer power supply. All items on the stereo worked including an Automatic music search that finds music breaks on tapes. The speakers even played a beep associated with button pushing on the stereo. However no sound from a tape or tuned radio station came out of the speakers. This is the question - why not? Was the power supply unsuitable? if not can you suggest another economical DC power supply to run a car stereo from house AC power for this type of workshop installation? Thanks.

Answer
You know what? there was no reason for the bad feedback, yes I did read your entire post.
That's it I've had enough of this crap.