I don't have a BSEE. I barely understand how electricity and electrical appliances function. But when I replaced the stock power cable on my McIntosh C220 preamp with an Empowered Cord by K-Works, I absolutely heard some clear, but subtle differences. The soundstage became more focused, and the level of detail retrieval improved, especially low level details. Remember, if the rest of your system is not highly resolving, you probably won't hear any difference in cables, but when your system is highly resolving, differences in cables and other connected items becomes clearly apparent. Notice that Notbananas has no system link, and did not provide a specific equipment list. Also, that "how could the last 5 feet of wire make a difference" thing is silly. Every stretch of wire has the potential to introduce extraneous noise into the attached components, so any improvement anywhere along the power-signal path has the potential to improve the performance of the attached equipment. Finally, to paraphrase Einstein: Not everything that counts can be measured, and not everything that can be measured counts.
