Ripping program can effectively renew old scratched CD making it sound better - like new. Even CD-R made from such rip will likely sound better than original CD.Not correct sorry, I can hear the difference between the original and the burnt copy I make for the car.
Also if you search there is a lab test disc you can buy I think it was the Pierre Varney double disc test disc suit, that has all the usual cd bench test tracks, but it also has a piece of music on it and then the same piece but 10 x generation copy. And you can clearly hear the degradation on the 10th copy.
Cheers George