Why do AC cords make so much difference?

I've come to believe that the quality of dielectric used can have a bearing on performance, in addition to shielding and current capacity. Hence I'm a fan of well-shielded all-Teflon designs. Write me for details if you wish. Cheers.

Cables are mysterious ~! But I think I am getting close to figuring it out. There is a great deal more to why power cords effect the sound of a component than simply "cleaning" the power or filtering out all the bad stuff.

Applying power to a conductor causes the conductor to resonate. The resonant frequency of the conductor establishes a base line for the cables sonic signature. But this is only the beginning.

As I understand it (I am not an EE) with 60Hz power there are 120 pulses per second. A pulse is the time when power can flow through the power supply transformer - when the rectified secondary voltage is higher than the stored voltage in the filter capacitor.

During the pulse, a heavy magnetic field is created and collapsed quickly within the power cord. Conductive material within reach of the magnetic field will dissipate energy through circulating currents, however some materials will attempt to store some of the magnetic field energy until the next pulse (or dissipate it as heat).

By adding material to a power cord one can change the resonant frequency of the wire, dielectric properties, and the pulse itself.

For example Taking a 10' long twisted pair of copper wire and applying more force - to twist it down to 6' in length will change the resonant frequency of the wire. Shielding that wire with tight braided copper, sticking that wire inside a tube & then filling with iron powder, fiberglass, sand, crushed aluminum, sawdust, crystals, or whatever, will again change the resonant frequency, dielectric properties and the pulse.

Each combination of materials will react differently to the magnetic field created by the pulse and presto... you have a new sonic signature in your system.

hmmm, thanks bwhite, that sort of makes sense to me.

so far though, swapping PCs in my system hasn't made much difference. other cables, both interconnects and speaker cables, i hear marked differences. but not PCs.

The filtering aspects would suggest a shielded cable. I can easily hear differences with unshielded cords, so there must be other factors. If you are comparing to a cheesy 18 gauge OEM cord there is a real difference. Perhaps it is the lower inductance, dielectrics, and wire size factors in high-end cords that make them sound better.

Has anyone here measured the capacitance between primary and secondary of a toroid transformer as opposed to an EI core? You will find about ten times as much capacitance with the toroid compared to a twin bobbin EI core which allows a sneak path for all sorts of RF nasties....Some IBM folks presented a study a few years ago to the IEEE of noise on power lines in major metropolitan areas and found huge spikes at 5mhz and 50mhz rather than the 27Mhz citizen's band they were expecting....With the profusion of toroid transformers, most of them center tapped to save on diodes, the noise is put right back into the neutral through the ground.......The vehicle I use to deal with RF noise is high capacitance and low self-inductance.....