If Power Cords Don't Matter...


First of all, I don’t own any high-end power cords, mostly because I can’t fit them behind my rack. Second, I am not trying to stir up controversy, as you will see from my question. I understand that the people who believe power cords make no difference argue that once the power gets into the component, the AC is converted to DC and the power supply of the component takes over completely. I think I have that right for the most part. So it that’s true, and it probably is from a traditional EE standpoint, why is it that I have not heard anyone say that power conditioners make no difference? I am not aware of anyone with a decent system ever saying that a Niagara or Triton or Audience teflon conditioner didn’t affect their sound, for good or for bad. So if the EE theory is true, wouldn’t power conditioners make no difference either? I have an Audience AR6T for almost 10 years and I think it made a big difference. BTW - I am not talking about Power Plants, which deal with voltage stabilization, which is a different topic.  Obviously, if your AC voltage is way off, it's going to cause problems.  
chayro
The problem is that it is not plain resistive load for 60Hz voltage.  Typical LPS draws current in very short spikes of extremely high amplitude (5 fold or higher).  These current spikes have high harmonic content (narrow squares), making cable's frequency response very relevant.  In addition all the energy delivered to load comes on the outside of the wires in electromagnetic field.  I'm not even sure if cable should have very low inductance and capacitance to preserve harmonic content of these current spikes, or should have medium inductance and capacitance to provide some filtering of it.  Gage of the wire should also be adequate to 5 fold current.  Also, there are extremely narrow spikes created by rectifier that, when backward polarized, is too slow to respond conducting in reverse direction, to rapidly snap back.  Transformer filters some, but portion of it gets out, I'm sure. 

I'm not saying I know why power cables make a difference, but it is not as simple as I = E/R  (Indian sees Eagle over Rabbit).
Caelin Gabriel takes the view that  the component sits between two power conductors: the hot and the neutral. AC power oscillates (alternates) back and forth at a 50-60hz rate. So power does not pour into the component at all. The component’s power supply is within a complex network of wires and connectors. Due to their obvious proximity, all of the wire and connectors can and do affect the performance of the component’s power supply.

From his view the power cord is not the last 6 feet, it is the first 6 feet from the perspective of the component. The further a noise source is from a component, the less of an impact it will have on the components power supply. The high-frequency noise sources that have the greatest impact on audio and video performance are the system components themselves
Actually you’re going to have to replace all of the wiring from the power station to your house because the polarity is off by 13.438°. Sorry.
These amplifiers also use filter capacitors and or chokes in their power supplies and the quality of those components is important also.
Both make a big difference in any system on any quality of decent gear for many reasons, but the big one is natural tonality, free cords make the gear work but aftermarket cords make the gear shine.