a short(?) primer
With power cords, the name of the game is Energy Transfer. Think of the house wiring,
even if it's a smaller AWG size than your PC, as a reservoir of energy just sitting there. If you stick a big pipe in it, you get a big flow, until the reservoir runs dry (overload) which isn't likely
Cords can have other attributes for sure (real or imagined) but E.T. is the big one.
FIRST** -- make sure your PC's, for at least your amp and DAC (or CDP), are minimum 10AWG. Everything else minimum of 12AWG. (14AWG is fine for low power stuff under 40Watts.)
SECOND -- make sure any cords used on digital gear (ANY digital gear, meaning anything with even just a digital display) DO have a floating shield (a shield connected only at the AC plug end.) This prevents the gear from TRANSMITTING digital hash (RFI) into the air.
THIRD -- Make sure that the cords on any source equipment that processes an ANALOG signal (preamps, tuners, etc.) ALSO have shielded PC's to prevent them from RECEIVING any kind of RFI from the air.
FOURTH -- There are some excellent reasons why more money buys a better power cord; but stick with conventional designs (avoid weird weaves or fancy spirals ;-) from reputable manufacturers. However, if you satisfy the three principals above, even with the cheapest models or DIY materials, you'll still be at least 80% there.
A word about OEM cords (the ones that came with your gear): Mostly they're pretty good quality, especially because they have WELDED air-tight terminations! IMO, they're usually one AWG size too small for the gear they come with, but why not transfer them to a smaller piece of gear and so on down the line?
OEM PC's have two problems: One is fixable and one isn't. If they
are shielded, it will say 'shielded' printed or embossed on the cord.
Unfortunately, for manufacturers to get UL approval on their gear, the shield on an OEM PC must be connected to ground at BOTH ENDS! This WILL keep the cord from broadcasting digital RFI, but it also creates a ground loop
, very susceptable to hum pick up. But, don't throw it away! Cut off the IEC plug and fit a new IEC plug, but
without connecting the shield to the ground pin of the new IEC plug. Voila! Floating shield! You can't improve the unshielded kind. It is what it is.
** Why do DAC's (or CDP's)
and amplifiers both require PC's with large conductor sizes you might ask? They're such different animals. For amps it's (somewhat) obvious, though it's not
just because of their larger power draw (good power supplies can store reserve power for a very short time.) Rather it has to do with the fact that even modest amps can (if they're allowed) draw amperage far in excess of the 20A wall power for just a fraction of a single (60) cycle. If the power cord doesn't restrict this, you get better dynamics (more 'headroom'.) That's why 90% of 'conditioners' are not good with amps. The other 10% are so expensive you might as well buy a power
regenerator and have the whole enchilada!
As for DAC's (or anything containing digital processing chips/circuits) cords with large conductors consistently seem to produce better sound (no one seems to know exactly why, yet!) but I
have noticed the difference when using a very clean source of power in the first place. Otherwise it doesn't seem to matter.