Power Conditioners and Cords

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#227
Walt and I worked on the development of his Super Regulators. We also worked on power supply design and I wrote my article on the measured RFI coming from different rectifier diodes. This is all in past issues of The Audio Amateur. I have been a friend of John Curl's for over 30yrs and we have shared audio knowledge.
 
#228
Didn't Jan Didden also work on super regulators? Just wondering since we don't have the article and if you still care about Mr. Fahey comments, maybe someone else will have a copy of the article or recall it? OTOH if you don't care about what Fahey says, then maybe no need.
 
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#232
Rick Miller said:
I task you with finding the magazine "The Audio Amateur" issue one 1994, page 26. I am not required to provide you with any information, if you want it go look for it. You are so negative, I am about thru with dealing with you.
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Why task ME with finding anything?
It is you who makes or backs extraordinary claims, then it´s you who provide clear direct proof, Logic 101.

Besides, nice try offering unavailable/unobtanium "data" as "proof"

Hi Brent,
I came across your site http://theaudioamateur.com/.

Do you realize that the entire content of the site is in violation of the copyright?
Ed Dell sold the Audio Amateur assets which include the copyright to The Audio Amateur magazine, I am the current owner. Here is a snippet of the contract as proof.

Please remove ALL the content related to "the Audio Amateur" magazine including any issue PDFs, JPEGs, and any other image or text reproductions of the magazine content.
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#233
Markw4 said:
PMA used to put on listening tests here that relied on Foobar ABX. PMA eventually trained himself to reliably pass ABX, but in the process of doing so he found that the criticisms of people tested with ABX were true. It requires a lot of sustained concentration to pass, which makes it difficult even when there is an audible difference (unless perhaps the difference is so gross as to be unmistakable in any state of mind and or degree of fatigue). Also, ABX in particular tends to be biased towards false negatives. Again that may arise from lack of sustained concentration and increasing fatigue. In other words what is easily audible once or twice starts to get much more difficult after 20, 50, or 100 trials. It starts to scramble the brain. But those kinds numbers are needed to generate statistics.

So, at the least it appears that ABX is more complicated than the simple model many people seem to expect, to the effect that it should be easy if there is a true audible difference.

Also, ABX is not the only blind perceptual protocol. There are some better ones with higher sensitivity, such as A/B. Any of the protocols can be done DBT. That's not the issue.
A lot more could be said on the subject, but its been discussed many times over a period of decades. No need to repeat it all here.
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ABX test has yet to be proven useful for most audio things. How does it help me sell or design anything? How does it help me enjoy anything? The reality that I believe is we simply can't make unassociated recalls auditorly. The thing is the associations don't have to be ones that nullify the blind in an ABX test. There hopefully are ways to do it so that we don't get nulls until the difference in measurements far exceed normal patterns of reputation in audio among even the most objectionist.

Markw4 said:
Doing a Bode plot implies looking at frequency response. That may or may not be all there is to it. In other words, looking at frequency response and finding little or no change does not necessarily mean all possible measurable explanations have been considered.

As DF96 (RIP) pointed before out noise can sometimes noise can sound like increased detail. Sometimes removing the noise may then leave a more dull type of sound.

In addition, Bruno Putzey measured a type of semi-signal-correlated noise from ferrite inductors that some people can hear.

Only point is that frequency response may not be everything one might want to take a look at to find some measurable change that correlates with reported perceptual changes.
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I don't think I've heard any affect of a ferrite clamp on a transport. But I can tell you I threw all of them in a box and don't open it or gave it away, I forget. Why? Because no matter what the measurements said I couldn't stand to listen to the music with them on. Whatever combination could work, I didn't find it. Maybe I could try harder, but it's like eating food I hate and trying to cook it in different ways over and over... when I could just eat something I like.

Markw4 said:
Question: Did the equipment tested use power inlet modules with internal ferrite filters? If so, how did you test without ferrites?

If you did test without any ferrites, then we might go on to talk about the other problems with the measurements. Thanks
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Good questions. Also why look only in the frequency range that the ferrites themselves don't usually work? They may have been using considerably more stable audio equipment than you find out in the field of the hobby... That's an ongoing issue with people that like to measure stuff, is they're often working with appliances that don't reflect the industry.

Markw4 said:
What makes you think the power company has low impedance at high frequencies? There are a series of power transformers that may be or may not be low impedance at high frequencies. And low impedance in what sense, differentially between line and neutral, line to ground, or neutral to ground?

Also, sounds you are talking about what we call diode commutation ringing of audio device power transformer leakage reactances. There is also distortion IR distortion of line voltage caused by peak rectified current flow. Those are two different things. That doesn't even start to get into what happens with SMPS, vaccum cleaner motors, etc.

The 'energy' involved doesn't necessarily have to go anywhere, no more than the voltage in a battery has to go anywhere. It can remain as potential energy. A lot of times voltage noise on the power line is not simply dissipated into a low impedance. If it was we wouldn't see so much voltage noise on the line, it would be more or less shorted out. But being shorted out doesn't mean its energy has turned to heat yet, it could turn into current noise and cause another set of problems.

The whole subject can be enormously complex. Its clear that the model you have in your head about what happens is quite over simplified, pretty much to the point of being more misleading than illuminating.
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I'd think most transformers in your neighbor hood have a good amount of leakage, not very tight regulation, etc, because otherwise they wouldn't do so well with changes in temp and would saturate a lot more. We know by code impedance to safety earth has to be 25ohm or less (which is actually really bad speaking from electrocompability aspects).

The AC environment tends not to "drain" anything, anywhere, as imagined by most. It might appear like that but the reality is the complex impedance is... complicated. Making a "short" in one location for noise may create ringing/other-stuff somewhere else (pretty typical). I'd go as far as to say our health can be affected by some poor decisions made with some appliances (audio or not) and "solutions" by EMI paranoid people. They don't know what they're doing, and they're inundating themselves with considerably more RF than necessary. (RF can influence microbiome)

Markw4 said:
If you just want to see if there is noise on the AC line, an RF spectrum analyzer, safely and carefully connected to show AC line noise, may be useful to try. Turning on or off something like a vacuum cleaner connected to the same outlet as the audio system should show pretty easily measured noise on the line (just to check that the test setup is basically working, of course, not as an expected condition while listening to music).
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To the point above, unfortunately you'd really want to have a network analyzer or many of them all around a house, and on multiple equipment pieces. You learn dick by looking at one piece of equipment, unless you are checking for something that accounts for the complex impedance. It's a little bit of a circular problem. And you can't just look at singular types of equipment because they respond to different types of non-60hz regularities (I won't call them irregularities since they go on all day, everyday).






I think the goal for equipment to be more immune to the AC power is commendable but that doesn't always mean the solution sounds good for a given circuit.

A lot (probably most) conditioners tend to knock back the sound from being "harsh" (dynamics?) because a lot of equipment and other aspects aren't that friendly sounding. But the "taming" is usually through saturation. Saturation affects the high frequencies first, audibly (people assume bass first). WHaaaAAAaa? Facts. Because how we hear bass the volume isn't very discernible without ques in the higher registry, but drooping voltage is very audible on higher frequencies that are short and lead. Any way it seems like the quality of tone and other aspects tend to suffer by willy-nilly "conditioners" for voicing a stereo. For other types of equipment these minor problems are probably inconsequential so a lot of commercial noise reducers are probably fantastic in a lab setting where you've got lots of independent regulated and/or constant current sources for parts of the appliance.

For a long time I've been a proponent of conditioning. I've got #10 GB going for AC filters right now, so I've released more than 900 of these out there. But as much as I like it, the more I have to proclaim caution from all that I've learned. It seems like many times a year I see products released doing the same old things.

Now to make everyone mad. I think power cables can sound radically different. "Why" it affects the sound is... That's harder to understand, and perhaps one day I'll release some sort of documentation but right now I have no reason to procure or produce sufficient data publicly. But what I'll tell you about is the defining moment where I was like "oh, these can affect the sound greatly, not just in subtle/imperceptible ways".

Take this with a grain of salt because I didn't tear everything apart and measure it (didn't have any gear with me nor permission). I went to a nice gentleman's house with a very nice stereo comprised of high end PS Audio pieces primarily. We swapped between the cable from the wall to the PS Audio regenerator. OMG. With one cable a song I love and know was beautiful, with the other it sounded BIZARRE and unlistenable. On another song it was the difference between a description of a baseball card on a bicycle hitting the spokes and the flicker of a movie reel (same sound, music video confirmed movie reel). Granted I'd say one cable was towards the foo-foo spectrum but it still has the basic tenants of a standard power cable (that "can't make a difference"). I also learned that the "regenerators" are not a convincing form of isolation/conditioning (from PS at least).
 
#234
Destroyer OS said:
Now to make everyone mad. I think power cables can sound radically different. "Why" it affects the sound is...
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There is no need to involve another level of mystery why different power cables could sound different with certain audio equipment. It is well known.

Audio signal is partially traveling between audio components through unshielded safety power earth wires. Depending on design, some equipment can be audibly influenced by that.
 
#235
Rick Miller said:
I task you with finding the magazine "The Audio Amateur" issue one 1994, page 26. I am not required to provide you with any information, if you want it go look for it. You are so negative, I am about thru with dealing with you.
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I pulled up the article -- "the news you failed to mention" - the diode ringing is a function of the junction capacitance of the of the diode AND the leakage inductance of the transformer. Knowing this you can design an RC snubber which tames the ringing at minimal cost. (The junction capacitance changes with applied voltage...) As posted earlier, it's a big issue in SMPS that Christophe Basso has written about for ON-Semi.

There can be issues with "Reverse PSRR" and regulator issues with crosstalk. I've read about it, but haven't experienced it.
 
#236
So the famous "mystery article" finally appeared?
And it says nothing like what was claimed here?
Why am I not surprised?

As of "solving resonances with snubbers", it was already mentioned here, many times.
But why mention a technically correct solution, which dos not help fill coffers?

Better claim fairy dust cables do Magic.

Which is actually their realm, of course.
 
#237
Here is a technical note issued by a manufacturer of diodes that talks about all of this. It has dates and names, which is why I'm citing it.

General Semiconductor QuikNoteTM No108

As for how to measure stuff other than 50/60 Hz on the AC mains, you don't need to rely on an Entech gadget that's no longer available. It's certainly easy enough to measure this now in a repeatable manner with the proper probe for isolation and an oscilloscope that has an FFT function or an actual spectrum analyzer. These two spectrum analyzers are certainly within the budget of most amateurs:

tinySA

A current probe of some kind is also needed because a lot of the unwanted signals, often generated by other audio gear in the system (!), are common mode currents.
 
#238
To make it easier, here's some current probe recipes:

EDN Probe

Vanderson Probe

Wyatt Probes

Väänänen Probe

Henry Ott, Ralph Morrison, Bill Whitlock, and Jim Brown have all published books, articles, and AES papers about common mode noise, differential mode noise, the effects of cables, the impedance of the AC mains, and much more. Much can be found with a simple internet search.

In addition, I'd point out the obvious that diodes are non-linear devices. They act as great RF detectors and mixers. When they are presented with a bunch of signals, whether from a refrigerator, a nearby AM broadcast station, a shortwave radio transmitter, undamped reverse current oscillations in a rectifier, and the rest, they will almost certainly mix all of them like a blender and add both differential and common mode signals into the system. Very few audio systems have been designed and executed like an Audio Precision test system that has superior isolation from the AC mains against both unwanted common and differential signals and similar isolation at the various guzzintas and guzzouttas, so you get what you get.
 
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#239
jackinnj said:
There can be issues with "Reverse PSRR" and regulator issues with crosstalk. I've read about it, but haven't experienced it.
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Just curious... How do you know that? Not trolling or attacking; just am interested in how you determined that you haven't experienced it.

Maybe your good audio system housecleaning practices help with this, too. It would be great to know.
 
#240
Markw4 said:
Here's my concern. I have been ranted at and had exaggerations made about me because I believe in listening. Been told measurements are the only thing that matters, etc. Listening is never reliable, on and on it goes.

In response I would say I think some people put more trust in measurements than may be warranted. Sometimes measurements are not done well. Often they are accepted without question if they support the person's confirmation bias. And so on. I will try not to rant.

In summary, I don't think measurements are necessarily automatically 'facts" nor that listening is necessarily automatically 'imaginary.' That's too polarized for me. Hopefully we don't have to make this as polarized as politics has become.
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I think there's another factor to consider with testing.

Let's assume that you have the very latest Audio Precision test system. It's almost certainly the most well researched, designed, developed, and executed measurement device in the history of electronically reproduced audio. AP has gone to great lengths to minimize the effects of AC mains noise on the power supplies. They've done what they can to minimize the effects of ingress. They have done heroic work to mitigate any common mode current loop effects. Does anybody dispute this? (Long ago, AP used to publish papers on all these topics on their website, but I don't know if they still do.)

All this effort and added cost minimizes the "Heisenberg" effects of the test system. That is, the device under test is operated in as ideal a manner as the test requires to make sure that what the results show are what the device can do in a kind of vacuum, not influenced by the test system. AP is justly proud of this and everybody should understand that this is what the tests represent.

But... That's not really complete. In actual use, the audio equipment has to operate within a system that's interconnected with not only other audio gear but also with the rest of the world, like the AC mains and whatever is attached to that. How much audio gear has been given the same consideration and execution as AP test systems have? (What would it cost??!!)

So, when was the last time you saw any sort of test of piece of audio gear that showed its immunity to common mode currents at the input? How about the rejection of signals conducted on the AC mains? How about immunity to signals outside the audio frequency spectrum? Or, on the mechanical side, the effects of vibration? And, in the reverse direction, how much unwanted signal energy is generated by the audio gear itself and passed onto other parts of the audio system?

Instrumentation engineers worry about this stuff all the time because they have to deal with it. There's been papers about this published over the years in the professional press that seemingly just gets ignored due to dogma or marketing influence.

Here is one example that probably will cause some discomfort:

Shield Current Induced Noise

If you didn't feel well and went to the physician and explained your issue, and then he measured your height, weight, blood pressure, temperature, and nothing more, all while you were lying down, and then told you that you were in perfect health, what would you think?
 
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