Can a better power cable make a difference if NOT plugged directly into an outlet?

Yes that is true, and it is all subject to bias for sure. I have never been one to buy into the super expensive cables. I am more a mid tier guy. 

A better way to think of this is that good power cables don't improve sound.  Bad power cables degrade sound.  an inadequate power cable won't support short (picosecond) bursts of high current needed for fast dynamics and sharp bass. 

Jerry

The way I see it, if you spend a bunch on cables it HAS to sound better right?

The way I see it, if you spend a bunch on cables it HAS to sound better right?

That's effectively claiming that everyone is subject to the fallacy of sunk costs. I think that's false.

Here's what I take as "true enough" on this issue:

Becoming an "experienced" audiophile requires

• accepting the idea that experiments do not have predetermined outcomes
• rejecting the idea that price is sufficient to make something sound good
• accepting the idea that experiments lead to mistakes from time to time and waste money
• accepting the idea that an experiment can yield no outcome or a worse outcome
• accepting the idea that one's system -- or one's system setup or power -- will be obstacles to an experiment capable of yielding audible results

So, yes -- one has to "try and see" but if one does not grasp the basic principles above, then one is actually just guessing. Perhaps that's the hardest pill to swallow around here -- that people claim to "try things out" to avoid wasting their money, but they do such a terrible job at controlling the variables that in order to save face (with themselves!) they find themselves pretending (to themselves and then to others, which just helps with the self delusion) that they hear something when they don't. An experienced audiophile would try to steer around that whole mess and just take their lumps.

Unfortunately the problems with your AC power is likely outside of your control. The power companies don't care how much interference or DC there is coming from their mains into your house. In a lot of cases they don't even maintain a solid 120 volts. I am a believer in power conditioners and use an Equi=Core 1800 MKIII, but ANY decent power conditioner is better than none. Any power cable that is capable of carrying more current is better than the typical 16 gauge lamp cord. But a power cord can only help from the socket downstream and unfortunately a lot of our power issues are upstream. A dedicated 20 amp circuit can be a big help. Just my opinion.