All cable(s) are important. Your 1st replacement is the Power Cord.
Which Cables Are of Most Importance?
In a hi-end system, McIntosh, B&W, which cables will give me the most bang for the buck between IC's, speaker, power and HDMI? Which cables are most important and which are least important? Will concentrating my $$ in any one or two cables give me the most bang for the buck?