This is the way I think of it and I maybe wrong so please add if I am way off base::
The electricity I receive at my humble abode is generated over 100 miles away. It goes through step up and step down transformers before it reaches my house. From there it flows through 25 year old 6 to 12 gauge wire until it finally reaches my outlet. How on gods green earth can a 6 foot cable running into my amplifier make a difference?
Thanks..