How does power cord affect a digital frontend?

I agree that short of a big power amp being severely choked with a puny cord, digital gear and / or highly advanced preamps seem to be the most sensitive to changes in AC power delivery.

I changed power cords on my Philips SACD 1000 and noticed what i thought was a huge difference. After changing the cords, my Brother looked at me with a smile on his face and said "you know we're not hearing that. It's all psycho-acoustics, right?". Swapping back and forth between the two power cords and charting the system's frequency response using test tones verified that there were not only audible differences, but measurable differences.

The weirdest thing about this is that the only real difference between the two cables is how the ground is implimented. Other than that, the two cables use the same identical geometry and materials. Due to the differences in ground wire configuration, this results in an impedance change along the entire length of the cable. Given the fact that the SACD 1000 has NO ground at the IEC jack from the factory, it is not electrically connected to ground. Just altering the impedance of the AC cord was enough to alter the frequency response of the player. This tells me that this player is WAY under-designed in the power supply. But then again, what digital gear isn't ? Sean
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Ok, it's clear that if a design of the power supply is flawed, it may be easely affected by anything. But what about manufacturers that are proud about their power supply design, such as MF, Simaudio, and others? It seems that under normal circumstances properly designed power supply is supposed to be quite immune to AC quality...

Dmitrydr, I have never heard a component that was not affected by power cords. I have tried a lot of power cords and a lot of components. There is an argument that a correctly designed power supply will be immune to AC cords, but I have yet to hear that.

KF

Dmitrydr, I agree with Tok2000. I think what you say is true in theory, but that there are no well designed power supplies.

My theory is that with a CDP the primary gains of a good power cord are to prevent noise from being injected back into the 120v system of your house by the CD player. I have an old old CD player. When it is playing interference shows up on my TV. If I put a couple of ferrite rings on the power cord the interference goes away.