Audio Systems: Radio problem, cadillac seville, antenna wire

Question
I just bought a 91' Cadillac Seville with the Delco Bose gold system in it and when I turn on the the radio I get a high pitched noise. We tried switching the radio out for one the same model out of a junk yard and the same noise was there. I went to a web page that said something about the amps in by the speakers being replaced. I just wanted a second person advise on the matter before I spend the money on parts I don't need. Also the person who owned the car before me had an after market in it and it work fine then. I just don't get it. Thanks for any help you can give.
    Michelle


Answer
the unit at front is not a radio,if there is  no ANTENNA PLUG it is not a radio only tape player with controls

you have to find the radio and replace it
it looks l ike this one but in your case it needs to be BOSE

http://cgi.ebay.com/ebaymotors/GM-CHEVY-88-94-TRUCK-RADIO-RECEIVER-BOX-AM-FM-AMP...

you  can find this in the midle of the dash closeto the glovebox
some other vehicles have it in the trunk

best way to find is by following the antenna wire from the antenna

good luck