Have a look at this (short) presentation/demo form Shunyata Research:
Shunyata make great claim to the idea that their mains cables are all about the science and can be proved to be effective. At the core of the demo Is a bit of true measurement. They measure the impedance of a (particularly) thin power lead and then a thick one (I mean more copper, not just more insulation) - the thicker cable is shown to have a much lower impedance. Now there is no magic or revelation to this and that bit is absolutely true and is scientific ‘fact’. It’s what comes after, all the conclusions drawn, that are questionable. In this vid Shunyata do something very common in the audio world. They take one element of accepted scientific fact and then extrapolate a whole bunch of unsupported ‘reasoning’ and product justification. What Shunyata don’t touch on is whether the lower impedance of the thicker cable* is relevant - can the component it is suppling make use of this aspect; unless it is a large Class A amp drawing lots of current the answer is likely no.
* Any thicker cable would have produced the same result - no need for it to be a Shunyata one.
