Do I need a power cable - if so what brand?

Take a look at Audio Art Cable power cords - only one that made a noticable difference in my system at a reasonable price

While I believe that those who may have contrary opinions are sincere, and many among them are astute judges of sound quality, for whatever reason I believe that opinions that power cords can make a significant difference in sound quality are utterly mistaken. I assume in saying so that your contacts are clean, plugs and jacks make secure contact, and wire gauge is adequate (all of which can be assured with some contact cleaner and a $5 power cord).

With probably hundreds of feet of wiring inside and outside of the house to the power company's transformer on a nearby pole (that steps down 10kV or so to 115V), and miles of wiring on the other side of that transformer to the power sub-station, what difference will the construction of 6 feet or so of wiring from the ac outlet to your system make? And even if it does make a difference, by what mechanism would the use of exotic and expensive materials in the cord correlate with improved sound quality? Putting it another way, are the differences essentially happenstance, which would mean that a cheaper cord might be just as likely to outperform a ridiculously expensive cord as vice versa?

I should add, to put my comments in perspective, that I have two degrees in electrical engineering and several decades of experience as an electrical design engineer, and more than 25 years experience as a high-end audiophile (Levinson, SOTA, Grace, Grado, various tube and solid state amps, Pentagram speakers, etc.).

Regarding power line conditioners, I'd imagine that their effectiveness or lack thereof would be dependent on the design of the power supply sections of your preamp and amp, and on the quality of the ac coming into your house. Which would mean that trial and error is the only way to tell.

Hah, I leave AudiogoN for two and a half years and return to find that the same arguments are still going strong.

Over the years, we've had EEs and physicists arguing both sides of this topic without resolve. It's funny when two physicists resort to insulting each others credentials.

SOMETIMES I notice a difference in power cords. The ones that have worked well for me are the original, affordable Virtual Dynamics Power series and the DIY VH Audio Flavor 4.

Boy, I missed this hobby!!!

In my 45 years in audio I have heard arguments like Almarg's many times. Better quality resistors cannot make a difference. Why would you put good wiring inside a speaker? How can a dedicated line do any good if the current has already traveled miles over transmission lines? This is usually called the objectivist position, if you cannot give a good reason for what you hear then you can't be hearing it. It is , however, not to be confused with science; it is a philosophical position unless you can prove that there could not be a difference. When I hear a difference between any item of equipment I always keep in mind that I may be deluding myself but generally when I hear a difference there is a difference. If Almarg is right then dedicated lines are a waste of time.

I can readily envision that in many homes dedicated lines for the stereo system may be helpful, notwithstanding my comments about power cords not making a difference. For instance, if other devices such as heaters or refrigerators are pulling large currents through lines in the house that are also supplying the stereo system, the system would see less voltage than if fed via dedicated wiring. The miles of wiring outside the house are typically much larger gauge than those within the walls, and are designed to support much larger currents without significant voltage drop. Also, dedicated lines could conceivably help isolate the system from rfi produced by those other devices.

In general, the better the design and quality of the power supply circuits within the system's electronic components, the less sensitive I would expect those components to be to dedicated vs. non-dedicated lines and ac line conditioning.