I think Lugnut is correct...if the camera doesn't have macro mode, you might need to be 2-3 feet away for it to focus. If it has macro mode, turn it on and see how close you can get.
Is there a focus lock? If so, you might also want to try focusing on something that's the same distance away and then aim at the amp instead. Your camera might have trouble focusing on something that's all black (maybe?? It's just a guess. One of my cameras is like that with gray).
Is there a focus lock? If so, you might also want to try focusing on something that's the same distance away and then aim at the amp instead. Your camera might have trouble focusing on something that's all black (maybe?? It's just a guess. One of my cameras is like that with gray).