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  3. 169085-1635

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

Showing 2 responses by kijanki

kijanki's avatar
kijanki
4,394 posts
 
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).
kijanki's avatar
kijanki
4,394 posts
 
Yes, demand has to be created.  Presence of the voltage in closed circuit creates current, hence magnetic field around the wire.  Load creates electric filed between the wires.  Electric and magnetic fields are always perpendicular.  They are like XY plane with vector Z (Poynting vector) showing direction of energy flow.  With AC both electric and magnetic fields change direction simultaneously, but Poynting vector (direction) stays the same.  Current itself is just a flow of electric charge.  Same amount of electric charge that leaves the source - comes back.  Energy is delivered on the outside of the wire.
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