It is possible to make bit-perfect copies with a computer, and pretty easy to prove to yourself that you did so correctly. I wouldn't worry about anything else until you go through the steps to prove or disprove this capability. My opinion is that if you're getting bit-perfect copies, you'll have no sound degradation and, by implication, if you're experiencing sound degradation, that you're doing something that causes the copy to not be bit perfect (ie, running it through the sound card).
Many disagree with this - speed of burning, type of CDR, etc. also being seen as key variables. They may be correct, but the accurate copies is what I'd check first.
Many disagree with this - speed of burning, type of CDR, etc. also being seen as key variables. They may be correct, but the accurate copies is what I'd check first.