Analyzing the power from the outlet

You can do this rather easily using a modern Oscilloscope. You will need to play with the resolution, try several different Hz, from 100 Hz to several thousand per division. This is easy to see. I am an electrical engineer and this is a simple thing to do. Depending on your area, congestion and the type of loads, power can be very dirty. Your electric company generally is not too concerned about this. Simply Google "Measure noise on AC line."

Besides providing a stable voltage, a regenerator will also reduce or eliminate noise and distortion that is present on the incoming AC, since it is what generates the AC that is provided to the components it is powering. Essentially it consists of an oscillator generating a 60 Hz signal (or 50 Hz in some countries) driving a high powered amplifier which in turn supplies that amplified 60 or 50 Hz signal to the connected components, and a power supply which converts the AC from the wall outlet to the DC which powers its own oscillator and amplifier.

But I understood the amplifiers require internal oscillators to operate? Why do you need to add an external oscillator?

The bandwidth limitations of the power transformer will significantly reduce the frequency components of the noise that are above a certain frequency. Noise on the incoming AC will also be reduced by filter capacitors and decoupling capacitors that will be present at various circuit locations in the design. It will also be reduced by voltage regulator circuits that are generally used in audio components, other than in the high power stages of most power amplifiers and integrated amplifiers. Finally, it will be reduced by what is known as the power supply rejection ratio of the amplification and other circuit stages which process the audio signal.

If all this processing is in the amplifier, why would it matter what you do to the power before it arrives at the amplifier? Maybe I'm missing something. But it seems to me that this is the design challenge of building amps. In theory, amplifying a signal is straightforward -- you buy an opamp and insert it into the signal path. But, addressing the departure from theory is what adds the complexity and $1000s to the price an amplifier. The designer building circuits into the amp that mitigate the problems created by the power supply. How could you market an amp that only functioned with a pristine power supply?

But I understood the amplifiers require internal oscillators to operate? Why do you need to add an external oscillator?

An oscillator is something that generates a signal. An amplifier is something which boosts some combination of the voltage, current, and power of a signal. What I was describing was a power regenerator, which takes in AC power from the wall outlet, and sends out "regenerated" AC to the components that are plugged into it. Power is regenerated in the regenerator by amplifying a signal generated by a 60 Hz oscillator which it contains. As I indicated, the regenerator's amplifier and oscillator are powered by DC which its own power supply creates from the AC it receives from the wall outlet.

If all this processing is in the amplifier, why would it matter what you do to the power before it arrives at the amplifier?

No design can reject noise and distortion on the AC it receives to an infinite degree. A substantial body of empirical and anecdotal evidence exists suggesting that designs at pretty much all price points can benefit sonically if the AC they receive is relatively clean.

Regards,
-- Al

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