It is really depends on if your system is neutral sounding or not. There is no definite answer to match each and every system. Assume your system is neutral, I use more refined IC (better grade fine silver and copper type) between the CD and preamp. I use less refined but bigger bandwidth ( thicker gauge silver and copper) cable between the preamp and amp.
If your system is on the warm and thick sounding, I would use more refined cable on the preamp to amp side and vise versa.
If your system is on the warm and thick sounding, I would use more refined cable on the preamp to amp side and vise versa.