Brownsfan's comment +1.
The importance of those benefits of upgraded power cords that are technically explainable (low resistance, good shielding against both noise pickup and noise radiation, noise cancelling geometry, perhaps minimization of resistance to abrupt changes in demand for current) are clearly dependent on the designs of the particular components in the system. Many are also dependent on the AC line voltage and AC noise conditions at the particular location.
Also, most or all of those particular benefits are readily obtainable at prices that are relatively low by audiophile standards, as well as at higher prices.
And to the extent that power cord upgrades may provide benefits that are speculative and/or not technically explainable, what basis is there to assume that what is being paid for in the upper parts of the price spectrum is not overkill, that provides no benefit relative to lower priced alternatives?
Finally, keep in mind that an ideal component power supply design, were there such a thing, would have zero sensitivity to reasonable variations in the characteristics of the incoming AC, and would feed zero noise back into the AC line. Perhaps it is too much to expect, but it seems to me that a more expensive component design should approach that ideal more closely than a less expensive component that performs a similar function. And therefore it should be less in need, not more in need, of the benefits that an expensive cord might provide.
IMO. Regards,
-- Al
