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Power-Cord/ Power-Conditioner testing

Holmz

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How would someone gop about testing power cords or power conditioners?
  • Maybe some broadband noise and 60 Hz on the plug end, and then look at the spectrum coming out of the amp end?
I am always sceptical of the claims, but have no reason to doubt that a choke wouldn’t alter what iOS presented to the amplifier. Irregardless of whether any of that sneaks out of the amplifier getting past its power supply.

I did see the Audioquest test here: https://www.audiosciencereview.com/...est-of-power-conditioner-by-audioquest.25467/

Should I continue to assume that the claims are in the domain of snake oil and B$?
 

escksu

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Should I continue to assume that the claims are in the domain of snake oil and B$?

Power conditioners do work. However they are not always needed. Most electronics already have built-in noise filters, some even have dc blockers.
 

escksu

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Just to show an example where power filtering is built into the equipment.

The top left part of the denon amp.





D_AVR-X1500H_slider_3_NA.jpg
 

audio2design

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Power cords are pretty much snake oil. Conditioners will provide benefit if you have a noise issue. Noise issues are system level. Ground loops, analog paths through EMI components and power lines, poor equipment design, etc. It's more about good architecture than if they check the right boxes for having parts. Often cheaper solutions, i.e. USB isolators, using balanced connections, etc.
 

jsrtheta

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How would someone gop about testing power cords or power conditioners?
  • Maybe some broadband noise and 60 Hz on the plug end, and then look at the spectrum coming out of the amp end?
I am always sceptical of the claims, but have no reason to doubt that a choke wouldn’t alter what iOS presented to the amplifier. Irregardless of whether any of that sneaks out of the amplifier getting past its power supply.

I did see the Audioquest test here: https://www.audiosciencereview.com/...est-of-power-conditioner-by-audioquest.25467/

Should I continue to assume that the claims are in the domain of snake oil and B$?

Power cords make no difference to anything except your bank balance.

As for power conditioners, I've seen user manuals for some components that assure the buyer that he/she will get no benefit from them. Myself, I was never tempted to spend money on a glorified power strip.
 
OP
Holmz

Holmz

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Power cords make no difference to anything except your bank balance.

As for power conditioners, I've seen user manuals for some components that assure the buyer that he/she will get no benefit from them. Myself, I was never tempted to spend money on a glorified power strip.

Some people I respect seem to believe that they make a difference.
I am trying to figure if they might be on some high noise situation, or if they are just really gulllible.

Since we have a few things in common, I am getting fearful that I could be gullible… but I am sceptical by nature.
 

NTomokawa

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Most electronics already have built-in noise filters, some even have dc blockers.
This is true, as far as my limited experience can tell. Some vintage equipment (built by Hewlett-Packard) even has those nice "Rifa" line suppression capacitors that love to announce their end of life by exploding violently.

but I am sceptical by nature.
A very good quality to have indeed.
 

blueone

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Some people I respect seem to believe that they make a difference.
I am trying to figure if they might be on some high noise situation, or if they are just really gulllible.

Since we have a few things in common, I am getting fearful that I could be gullible… but I am sceptical by nature.

When you say, "they make a difference", I assume you mean power conditioners? They can, but usually don't. When I lived in San Diego I had some noise issues that were audible from a couple of line-level components. I plugged the components into an AC-AC isolation transformer and the problem went away. I never understood why, because both components had their own AC/DC power supplies with transformers, so it made no sense to need the isolation transformer, but there are times that when I find a solution to an annoying problem that isn't obvious why it works I just give up and go with it. Usually that happens with automotive problems, but that time it happened with audio electronics. After we left San Diego the problem never reoccurred, and the isolation transformer sits in a closet.

Spend your money on better speakers.
 

JSmith

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Some people I respect seem to believe that they make a difference.
Please look at these review and test threads;






JSmith
 

jsrtheta

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Please look at these review and test threads;






JSmith

Best evidence.
 

audio2design

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Best evidence.

Not really.

These are non system level tests, indicative of a single setup, fairly isolated itself, feeding into an AP (with an isolated analog input).

The fact it only filters at > audio frequencies is also meaningless as bursts at high frequency can demodulate to audible frequencies.

I have lab quality equipment, you know that Agilent, Tek, NI, Chroma, etc. that everyone assumes are designed perfect, nicely isolated etc? I am often chasing noise gremlins in test configurations due to inherent leakage currents through the equipment. A single piece on its own looks great. Throw in a few pieces of test equipment, a piece or two of target hardware, a PC/laptop with a non-isolated USB, and all bets are off. USB isolators are great by the way!

The fact a product has a transformer only provides a level of isolation. EMI caps have leakage current, switching transients cross isolation barriers, etc.

Now audio is pretty benign overall, but you can't extrapolate from effectively a test of a single piece of isolated equipment and claim it will be so for all cases with more complex systems with a lot of interconnections. It simply is not true.
 

JJB70

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Well designed equipment already conditions power and does not need external power conditioning. However there are outliers cases in areas with extremely dirty electricity supplies where external power conditioning may be necessary. In such cases I am guessing people are familiar with the issue as it is not an AV problem but a general one.
 

escksu

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That's mainly a standby and logic switch mode power supply.

Its more than that.

IF you enlarge that photo, there is a common mode choke (white circular coil). Beside it is a yellow capacitor (could be X or Y cap). It appears to have blue MOVs as well to protect against voltage spikes.. There are also junction diodes which appears to perform DC blocking.
 

escksu

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This is another photos of a consumer blu ray player. Page 4 of the document, you can see the power board. Again the common mode choke and 2 yellow caps (should be X, Y caps). the 4 tiny diodes above the caps should be DC blocking diodes.

What I want to say is that power filtering is done for most consumer electronic devices. It is important and should not be something optional. ITs also in your power brick adapters.

Power filtering is important but most devices do not need an additional power conditioner because they already have their own filtering. However, not all devices have the necessary filtering. Some skipped it on have very limited filtering to cut cost.


Also, you don't need those expensive power conditioner, its a waste of money.
 
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bladerunner6

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Some people I respect seem to believe that they make a difference.
I am trying to figure if they might be on some high noise situation, or if they are just really gulllible.

Since we have a few things in common, I am getting fearful that I could be gullible… but I am sceptical by nature.
I suggest you find different people to respect for advice on audio equipment.
 

audio2design

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Its more than that.

IF you enlarge that photo, there is a common mode choke (white circular coil). Beside it is a yellow capacitor (could be X or Y cap). It appears to have blue MOVs as well to protect against voltage spikes.. There are also junction diodes which appears to perform DC blocking.

Yes there is some very basic emi components, what looks like some y-caps from line/neutral to ground, a single common mode that's not going to cover that wide of a frequency range, some MOVs, but those diodes are most definitely not for DC blocking. That's still a standby power supply and if you look where the transformer connects it's fairly early in the circuit. The standby power of a large transformer it's too high by modern standards so a supplemental always on supply is there.
 

audio2design

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@escksu, please don't embarrass yourself by posting more pictures of stuff. Identifying diodes as DC blocking when they're doing nothing of the sort does not show that you know what you're talking about. I've spent a good part of my life designing stuff just like this. Keep in mind most of those emi components are not for keeping emi out of the product they are for keeping emi from the product out of the AC line so that they pass FCC and other worldwide standards. That's not to say that they don't help any other direction but that's not the primary purpose. Y-caps specifically are often more of a hindrance than a help for external emi.

Not sure why you linked in the laptop adapter because it also has whatever necessary emi filtering to pass FCC. You can see the mid frequency common mode inductor and the architecture of the power conversion with the large bulk capacitor on the input reduces most of the low frequency switching transients so that it's still passes FCC.

The Blu-ray player looks like the emi components you would find on almost every single stage flyback power supply to pass FCC, not to protect from external noise.
 
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Killingbeans

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Some people I respect seem to believe that they make a difference.
I am trying to figure if they might be on some high noise situation, or if they are just really gulllible.

Since we have a few things in common, I am getting fearful that I could be gullible… but I am sceptical by nature.

Power cables make zero difference.

Power conditioners might help in some nightmare situations. But as audio2design points out above, in those cases there's probably cheaper and more effective solutions to choose from.

It's a band-aid you apply in hope of fixing grievous problems with noise and/or interference. Adding it to a perfectly functioning system won't open the floodgates to a sea of manuka honey and angel singing.

And you're not gullible, just human. We all believe in some sort of BS or another. Weeding it out 100% is impossible, and relapses happen.

All you can hope for is a good sanity check at the right moment.
 
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