How does power cord affect a digital frontend?

I think it does, but can anybody explain why and how?
I could guess how current demanding amp may be affected by weak power cord, but what about CDP?
From my experiences, power cords effect digital the most! They need clean, refined power and current isn't as important as it is with amps(and other high current components). Even a basic power cord designed to work on digital will get rid of some of the digititus and smooth things out- i.e. larger soundstage, greater transparency, greater image depth, texture/body, a more palpable presence- basically it makes things MUCH differnt. Most cases that different is better and then different power cords have different strong and weak spots- one may be super transparent at the expense of some body; etc....

In other words try a few and see what you hear, a lot of power cord companies offer in home trials so you have little if anything to lose.
I agree with Tireguy. I notice larger improvements on my front end equipment including the pre. and transport.
I think most tweaks are more significant on the front.
I know it does too, but I don't understand it. What exactly is going on with different powercords? What are the physics behind how a powercord effects a component. Is it simply that it gets the electricity more easily through better powercords, or does each powercord contribute to/detract from the electricity in some way that effects the sound (greater transparency, larger soundstage, etc)? Are there any guidelines for pairing powercords with components or is it trial and error?
I found even more than the powercord was the power itself & undoubtedly you have read about (or have) dedicated lines with high quality outlets. Someone once made the comment that the powercord was not the last 5' of the electrical chain but the first 5' & should be given the requisite attention. OK, I added on that last part but if the AC is not up to par, nothing you do can fix it.
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
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.

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.
The power wiring in the wall will usually have harmonics of the 60 hz from radio signals, motor back-feed, fluorescent ballasts (which add current to the neutral), and other electric fields from power users on the same grid (elevator motors and machinery in the building across town.) All this noise gets into your power supply. The ability of the PS to reject this noise varies in proportion to its cost. Also, digital switching generates noise from within the cdp, further adding to the problem. The active circuitry gains up any signal, including noise, which is passed along as distortion to the components downstream.

A good power cord will filter some of the ac noise entering the power supply. This can reduce the noise from from coupling to the active circuits via stray capacitance and being gained. It can also reduce the noise generated by the cdp from reinfecting the power wiring by filtering the EMI/RF fields both from the cdp and common mode noise that can couple onto the power cord.

I have noticed the greatest improvements in digital front end from power cords that do a good job in filtering noise, such as the MIT Z-II cords, for the above reasons - I think. Cords which do the same job of filtering for a lot more money should be looked at with hand guarding wallet, IMO.
The greatest improvement with digital gear (Sony SCD 777 ES and Esoteric DV-50) has been with the JPS labs Digital AC. (See Art Dudley's article in the April "Stereophile".) It really works. It takes about a week of continuous use to
"break-in", but the improvement is not subtle.
I don't claim that it doesn't exist, I'm just curious how it happens. I'm not really clear how presence of noise in AC line may affect digital signal. It may affect an analog stage in CDP, but if the data is being transferred via SPDIF interface, the analog stage is not really involved... I realize that digital signal may be affected by 'bad' SPDIF cable, especially if source or/and receiver are not exactly match to SPDIF specification, resulting in jitter. But how jitter may result from AC power even containing some noise, it anyways is converted to DC for a digital stage? The digital signal is "formatted" by crystal oscillator, not by 60Hz wave.
Dmitrydr, I now better understand what you are asking. I suspect that as with all conversions to dc, there are better and worse and that that cords and filters make the conversion easier.

All I can say is that on my Lindemann with a digital as well as analog ac cord, I can hear substantial difference among the cords I use on the digital as well as analog as well as an enormous improvement using the Loricraft balanced power supply.
I agree with SeanandTaylor that the laser mechanism in the CDP is a culprit in interferring with the power that feeds into the rest of the system. That is why it's best to isolate the transport from the rest of the system, and a good PC can help do this.

I am guessing, but I think the material that CDs are made with (the shiny stuff) can attract airborne RFI/EMI which can be transferred to the rest of the system as well either through the power or signal lines. I use a sheet of ERS cut into the shape of a CD to use as a CD mat and works pretty well.