Analyzing the power from the outlet

Hello Al
Thank you for the response. I know you are a highly accomplished designer so I appreciate your sharing your insights.

Ok. So that's a regenerator. If I understand it, you are recapitulating a perfect sin wave.
-- an amplitude of 120 RMS and a frequency of 60 hz.

But, when people here talk about power conditioners, they are not necessarily talking about regenerating the ac signal. They are talking about other things such as power filters (Shunyata). Is a power filter actually a regenerator? Do they filter the noise off the power by regenerating the wave form and the side effect of the regeneration is to remove the high frequency noise?

Or is a power filter a different device?

Finally, there is the business about the balanced power devices. As I understand this, it switches from 120-to-ground to 60-to-60 and then subtracts the common mode noise. But, again, isn't that the basis of the front end of an amplifier. Isn't the first component in the amp a transformer or differential amplifier subtracting common mode? And doesn't an amplifier transformer switch from 120-to-ground to 60-to-60?

CJK, a power filter/conditioner puts the incoming AC through a relatively simple circuit which provides some degree of noise reduction. It may also include a provision for surge protection. It does not “regenerate” power.

As can be surmised from the description I provided earlier, a power regenerator capable of supplying sufficient power for a typical audio system will cost a substantial amount of money. Many (although certainly not all) conditioners are available for much lower prices than most regenerators, or at least regenerators that are well designed and have substantial power capability.

Your question about balanced power is a good one. Yes, the outputs of the power transformer in an audio component will often be balanced relative to ground. (Although keep in mind that the power transformer will often provide multiple outputs, at various voltages, some of which may be balanced and some not, for various reasons). However a main goal, and perhaps the main goal, of balanced power is to minimize noise on the AC safety ground. AC safety ground is connected to the chassis of the component, and much of the noise injected onto the chassis will inevitably find its way to the circuit ground/signal ground of the component. In some components circuit ground and chassis are even connected directly together, and in many others they are connected together through a low impedance.

The component’s power transformer cannot help with respect to noise coupling through that path, because it is not in that path. And in fact it can itself contribute to coupling of power line noise onto the component’s grounds, via stray capacitances that will inevitably exist within it.

Also, btw, a major source of the noise that balanced power can help reduce will be the components themselves. See this paper for a somewhat simplified overview, and this one for greater detail.

On another note, glad to see you’ve made some progress with the problem being discussed in your other thread.

Regards,
-- Al

There's a series of threads on Polk Forums, where one of the members, a college professor, ran a series of measurements on power line noise and line conditioner/tweaks. AFAIK, its the most extensive type of evaluation conducted by a product owner on any forum.

http://www.polkaudio.com/forums/showthread.php?71333-Studies-On-Residential-Power-Line-Noise-Part-1

http://www.polkaudio.com/forums/showthread.php?71382-Studies-On-Residential-Power-Line-Noise-Part-2

http://www.polkaudio.com/forums/showthread.php?71545-Studies-On-Residential-Power-Line-Noise-Part-3-PS-Audio-Power-Plant-Premier

http://www.polkaudio.com/forums/showthread.php?72539-Studies-On-Residential-Power-Line-Noise-Part-4-PS-Audio-Premier-SC-Power-Cord

http://www.polkaudio.com/forums/showthread.php?75093-Studies-On-Residential-Power-Line-Noise-Part-5-PS-Audio-Power-Port-Premier

http://www.polkaudio.com/forums/showthread.php?79010-Studies-On-Residential-Power-Line-Noise-Part-6-PS-Audio-Soloist-Special-Edition

http://www.polkaudio.com/forums/showthread.php?82496-Studies-On-Residential-Power-Line-Noise-Part-7-HiFi-Tuning-and-Isoclean-Fuses

http://www.polkaudio.com/forums/showthread.php?83644-Studies-On-Residential-Power-Line-Noise-Part-8-Audio-Grade-Fuses-For-Home-Theater

Here are a few things that proper power conditioning can correct:

The most important is the 5th harmonic. Fluke instruments printed a white paper on this subject some 20 years ago. The 5th harmonic (300Hz in the US) can cause power transformers to become noisy, power rectifiers to radiate noise, and certain types of AC motors to possibly spin backwards.

DC on the line can cause saturation of toroidal transformer cores and should be blocked else the transformer can become quite noisy. A second harmonic on the line can do the same thing.

High frequency noise can cause problems in digital gear but otherwise is not likely to do much to analog gear if the power supplies are properly designed.

Any skeptical engineers out there? If so, consider the fact that the best power conditioners were made by companies that directed their product at the commercial/industrial market. Elgar is one of those companies. If clean power did not help, companies like Elgar would not exist. If there is skepticism, it exists out of ignorance, which is easily curable.

Great inputs from Ralph (Atmasphere), as usual.

Gbart, thanks also for calling attention to the papers presenting the many measurements. I haven't taken the time to read most of them yet, but FWIW I would suggest to those who do read them that whatever conclusions are reached by the author be carefully scrutinized, and not just accepted at face value. I say that because not long ago, in connection with a thread here on fuse directionality, I did thoroughly review Part 7 of those papers, relating to fuses. My comments on it were presented here.

Regards,
-- Al