I agree with Tvad (and also respectfully disagree with Hbarrel) and here is a partial post I made to another thread, but first a quote:
"It's all about energy transfer." -- (from a phone conversation I had with Jim Aud of Purist Audio Design)
You may ask, why use cords with conductors that are bigger than what's in the wall? The answer is "Energy Transfer" And the more power a component consumes (amps) -- AND/OR -- a component's frequent need for "nano-bursts" of power (DACs are in this category) the more a bigger conductor size will contribute to improved sonics. OK, you say, but if my wall wiring is 12 AWG, what's the point of using a 10 AWG power cord?
Once again the answer is Energy Transfer. Let me state some obvious facts, and then try and provide an analogy: Alternating current is stored (in your wall circuits) as a potential -- it doesn't do anything until you connect a load of some sort. BUT, that potential changes direction (polarity) 60 times a second. And its strength varies 60 times a second (from 0 volts to 120 volts). In other words, it's not really a "consumable" like natural gas, that gets burned up when it comes out the other end of the pipe (that would be more like direct current, where the battery eventually runs down ;~) No, AC just "sits there" and changes back and forth 60 times a second.
OK, so here's my analogy: let's say the house circuit is a reservoir (imagine the ocean) of energy that's constantly changing in pressure (potential) and direction (polarity) -- (imagine the waves at the shore, rolling in and out.) When you plug your PC into the wall, it's like sticking a pipe into the ocean at the shoreline. The bigger that pipe is, the more accurately the potential and pressure at the other end (the component) will reflect what's going on in the ocean itself. OK, imagine the pipe gets smaller. The pressure at the other end is still the same, but if you use some of it to do some work, it'll take a second for the pressure to build back up (poor energy transfer). AND, if you add to that, the fact that the direction of the "pressure" (pushing in and pulling out) is supposed to change 60 times a second, then the smaller pipe is going to create a lag in polarity changing. That doesn't mean you're going to see 50Hz AC instead of 60Hz, it means that spots of frequency cancellation are created in the "pipe" which further keep the available potential (pressure) from being realized at the other end.
Moral of the story: Especially with 15A wall circuits (as opposed to 20A) and except for low power stuff, like TTs, phono preamps, tuners, cassette decks, CDTs (but not DACS) use the biggest sized conductor power cords you can, even sacrificing fancy shielding and insulation for conductor size if you have to.
That's been my experience so far . . . . . .
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