Battery drain on a 1998 Cadillac Seville STS

What is your question?

So I've had the car for about 3 years now and runs great. It's an older car, so I expect problems and maintenance. The battery keeps dying over 2-3 days from sitting. I took it to a dealership and they told me it was the radio. They pulled the audio fuse from the fuse box and recommended to change the radio. The car started fine, no radio. I changed the radio and connected the fuse and it died. Now could it be the amp? Please help. John