Power Conditioner recommendations...

Oh, boy. I didn't mean to get this involved. I just wanted to make a comment that they do not thwart all noise.

It has to do with the inductance within the magnetic fields (inductive coupling), a shared ground (even though hot and neutral are physically not a closed circuit), Capacitive coupling from conductors placed close together, allowing signals to "leak" from one to the other. Much of that has to do with layout and design, the frequency and voltage changes. Then there is your typical EMI/RFI which can be transferred across physical gaps, just like with a physical connection, and then there are the regenerator itself that may have limitations (some only go up to certain frequencies) and additional filtering is needed or added. Heck, the regenerator itself may even add noise.

While regenerators, isolation transformers and galvanic isolation devices can provide up to a significant change, depending on the noise that's present on the line to begin with, that does not mean that they automatically isolate all noise coming from the outlet and your homes electrical system. It's not like they are a Faraday cage for every type of electromagnetic noise, and even if it were? You would still have the physical ground connection to wreak havoc.

That's about as far as I'd like to get into it, there is more but this is the gist. This subject can get deeeeeep into the weeds. I didn't even touch leakage, vibration noise or a host of other things that can affect how one of these devices can transfer or even introduce noise into the system. What they can do (as mentioned before) is make a near perfect to perfect sine wave. But that's not all there is that we need to be thinking about when it comes to getting clean electrical for audio. There is much more to audio than a simple sine wave.

Plus, if you are streaming? HA! You just opened up/connected yet another can of noise (even with galvanic or optical isolation)....but I ain't goin' there. That's way too deep.

Hopefully, this answers your query. I am not sure about the differences or effectiveness between the units aforementioned.

Tom

skipshot12 wrote: »

Truly a rabbit hole right there.

No doubt.

Tom

Got my Puritan psm 156 at a great price, not looking anymore.

nooshinjohn
nooshinjohn Posts: 25,848
November 7
The name Richard Gray has popped up a bunch in this thread... worth a look? I find them to be well under the price tag of others in this group.

Absolutely worth a look.
The "Richard Gray Substation" products are the ones with an internal transformer. Awesome gear.
There may be another Richard Gray with a TX but can't remember the name of it
I think the other Richard Gray power power products are filters & surge protection.

Personally, I prefer the power products that can change/adjust & stabilize the output voltage.
There are other ways to adjust and stabilize voltage but I prefer it be done via a transformer.

That air gap in the TX is as if you had a transformer at your house, from the power company, that only you are on. Not literally the same but.... semantics.
Gap's different, build shape is different, not submerged in oil but, it's what we called a dry pack transformer.

I would say that a Toroidal TX, in the power conditioners that use one, could be referred to as a Dry Pack TX?
I'm just a dumb-asst retired lineman and think we'd need an electrical engineer to actually verify that statement....

"Investigated".

I have to laugh at that one. Sorry bro' but it is what it is.

Jesus...still a rebel?

LOL.

Tom

Active Power Factor Correction (PFC)

For higher power applications, active power factor correction (PFC) circuits are often integrated into the AC-DC stage. PFC circuits not only improve the power factor but also regulate the DC bus voltage and can actively reduce harmonic currents drawn from the AC source. By shaping the input current to be sinusoidal and in phase with the input voltage, PFC circuits inherently mitigate some forms of noise from the source (Power Electronics Handbook).
DC-AC Conversion (Inversion)

The second stage is DC-AC inversion, where the DC voltage is converted back into an AC voltage. This is typically achieved using power electronic switches (e.g., MOSFETs, IGBTs) in a switching topology.
Pulse Width Modulation (PWM) Inverters

Modern inverters primarily use pulse width modulation (PWM) techniques to generate an AC output. In PWM, the DC voltage is switched on and off rapidly, and the width of the pulses is varied to create an average voltage that approximates a sine wave. The switching frequency of the inverter is typically much higher than the desired output AC frequency (Power Electronics: Converters, Applications, and Design).
Output Filtering

The output of a PWM inverter is not a pure sine wave; it contains high-frequency switching harmonics. To produce a clean sinusoidal output, an output filter (typically an LC filter) is essential. This filter attenuates the high-frequency switching components, leaving a nearly sinusoidal AC voltage (Power Electronics Handbook).


CONTINUED...

Noise from the DC Link to the AC Output

Ripple and Low-Frequency Noise: Any significant ripple or low-frequency noise present on the DC link will be modulated by the inverter and appear in the AC output. While the output filter is designed to remove high-frequency switching noise, it may not be effective at attenuating low-frequency ripple originating from the DC link (Power Electronics Handbook).
High-Frequency Noise (Switching Harmonics): The primary noise generated by the inverter itself is the high-frequency switching harmonics. The output filter is specifically designed to attenuate these components, aiming to produce a clean sinusoidal output. The effectiveness of this filter is crucial in determining the quality of the output AC (Power Electronics: Converters, Applications, and Design).
EMI/RFI: The high-frequency switching of the inverter can generate significant EMI/RFI, both conducted and radiated. Output filters, shielding, and proper PCB layout are essential for mitigating this noise (Electromagnetic Compatibility Engineering).

Isolation and Attenuation Mechanisms

Several mechanisms are employed in AC-DC-AC converters to isolate and attenuate noise from the original AC source:

Input Filters: These are typically passive filters (LC or RLC) placed at the AC input to attenuate common-mode and differential-mode noise, including EMI/RFI and some transients, before they reach the rectifier (Electromagnetic Compatibility Engineering).
Active Power Factor Correction (PFC): As mentioned, active PFC circuits can actively shape the input current, reducing harmonics drawn from the source and providing a degree of isolation from source harmonics (Power Electronics Handbook).
DC Link Capacitors: Large DC link capacitors are essential for smoothing the rectified DC voltage and absorbing the pulsating current drawn by the inverter. They act as a low-pass filter, attenuating high-frequency noise on the DC link (Power Electronics: Converters, Applications, and Design).
Output Filters: LC filters at the inverter output are critical for removing the high-frequency switching harmonics generated by the inverter, ensuring a clean sinusoidal AC output (Power Electronics Handbook).
Galvanic Isolation: In some applications, a transformer is used at either the input (before rectification) or the output (after inversion) to provide galvanic isolation. This physically separates the input and output circuits, preventing the direct conduction of common-mode noise and providing a safety barrier (The Electrical Engineering Handbook). An input transformer can also help in attenuating common-mode noise and some differential-mode noise from the source.
Control Algorithms: Advanced control algorithms in the inverter can actively compensate for disturbances on the DC link and improve the quality of the output AC waveform, further reducing the impact of noise (Power Electronics: Converters, Applications, and Design).

Conclusion

In summary, a device that converts AC to DC and then DC to AC is designed to produce a clean AC output, ideally isolated from the noise of the original AC source. However, perfect isolation is an engineering ideal that is approached but never fully achieved.

Harmonics from the original AC source can propagate through the rectifier, especially if it lacks active PFC, and appear as ripple on the DC link, which can then affect the AC output. Active PFC significantly mitigates this.
Transients and EMI/RFI from the AC source can couple through the rectifier and appear on the DC link. Effective input filtering and surge protection are crucial to attenuate these.
The DC link acts as a buffer, with its capacitors absorbing much of the high-frequency noise. However, low-frequency ripple on the DC link can still be passed to the AC output.
The inverter's own switching action generates high-frequency noise, which is then attenuated by the output filter.

Therefore, while the converter significantly attenuates and transforms the noise characteristics, it is generally not entirely immune to passing some form of noise originating from the original AC source. The extent to which this occurs depends on the sophistication of the converter's design, the quality of its components, and the effectiveness of its filtering and control mechanisms. A well-designed AC-DC-AC converter with robust filtering and, potentially, galvanic isolation, can provide a very high degree of noise attenuation, but some residual noise, particularly low-frequency components or highly energetic transients, may still find its way to the output.

So, you stated that you "investigated"?

LOL

Tom

We will agree to disagree on this.

Tom

So, can you tell us otherwise?

Tom