Is This Possible (Or Worth the Trouble)

I have a '93 Camry, great shape. The head unit stereo still works, but the CD player does not, so I'll be replacing it. The car came with the premium sound system which meant that there is a dedicated amp under the passenger seat, which still works. This is not a regular amp, but one dedicated to the head unit. However, I have been informed that it can be reused with an aftermarket head unit, if it is wired correctly. To your knowledge, is this correct, and if so, where might I get a correct schematic for such a conversion? A usually good source: installdr.com sheds no light on this one. thanks