Rear Amp location

I have a 96 A4 with the bose delta stereo system. I understand there is two amps, one built into the receiver (??? yes or no ???) and one for the rear two speakers. Where is the amp for the rear, I cannot seem to find it. is it in the front or rear of the vehicle? thanks

Mine's a 98, so I don't know if it's the same, but mine's tucked up in the trunk near the rear driver's side speaker.

Is there a front amp or is it built into the receiver?

I haven't seen a front one anywhere, but then again, I haven't really looked. It could be in the reciever. I do know for sure that there's a back one though.