Would you guys buy one of this cable

[gmgraves]

Apparently there is an interaction between the type of power cord and the power transformer.

IIRC, John Swenson stated that the chosen values of his snubber components on the secondary side of the transformer, (before the rectifier diodes) results in far less variance of SQ due to the use of different power cords. Transformer resonances come into play here IIRC.

 

 

Apparently, there is not. Work the math. And even if there was, the component doesn't care. All it's looking for is the correct DC voltages it needs to operate. While it's possible for noise from a dirty AC line to get past the component's transformer and into the signal, a mere power cord isn't going to help with that. You need a good line filter if you have dirty AC.

[gmgraves]

I tried a couple of "audiophile" power cords (~$150) on my power amp and could not hear a difference. I sold them, went back to generic Tripp Lite 14AWG SJT cords (~$10 from Amazon), which sound exactly the same. So, while YMMV, my opinion is based on my own experience. I'm not interested in mocking anyone, just trying to save someone else the price of an education.

 

 

You got just the result that science predicts you should get.

[sandyk]

No, I would pass on those. Fake alarm.

 

Quality termination is important and the outlet comments I agree with too. This is more to do with avoiding those tiny little sparks when there is not a tight fit. But those Hubbell hospital grade ones are cheap.

 

For me shielding is important too as I do not want the EMI field of the power cord to interfere with audio / video signal cables. I use a simple Tri-Field EMI meter to check. Around $100-150 is about max I would spend for quality, which still seems pricy. But get one from a reputable dealer, or roll your own if interested.

 

Power boards are an even bigger problem than mains wall sockets, and outlets can become loose and cause problems. Shielding of the mains cable can be quite important, especially if you are unable to put a suitable distance between the mains and signal cables.

[sandyk]

Apparently, there is not. Work the math. And even if there was, the component doesn't care. All it's looking for is the correct DC voltages it needs to operate. While it's possible for noise from a dirty AC line to get past the component's transformer and into the signal, a mere power cord isn't going to help with that. You need a good line filter if you have dirty AC.

George

I said nothing about RF/EMI getting into the amplifier .Correctly chosen Snubbers help to prevent interaction between the rectifier diodes, transformer and the mains cable, which greatly reduces wideband RF/EMI garbage getting back into the mains and also helps to prevent transformer resonances .

If you want the full explanation, I suggest that you PM John Swenson.

 

Alex

[sandyk]

You got just the result that science predicts you should get.

 

INCOMPLETE SCIENCE ! Much depends on the power supply area of the device itself.

[jiminlogansquare]

I have posed this question elsewhere and have never received a satisfactory response; but what the hey, it's Valentine's Day, and I'm feeling giddy.

 

The Question: How do you know whether your power is dirty?

 

Corollary Question1: What *exactly* is dirty power; how does it differ from clean power?

 

Corollary Question 2: How does one test for dirty power -- i.e., how is it measured and how would I evaluate my AC to make sure it is not dirty (or *too* dirty)?

 

I would like an objective way of testing to see whether I have dirty power before investing in a power conditioner to cure that problem. A waste of money if I don't have the problem, and even if I got a satisfaction guarantee, buying/installing/testing/removing and shipping back is always a hassle and a disappointment.

 

(Pro Tip: Among those answers I have received elsewhere that were fundamentally unsatisfactory, the worst and most common was "You need to just install [x] and listen to see whether it makes a difference!" Nope. See above. If power cannot be objectively evaluated as dirty or clean, then I am not inclined to screw around investing time, money and frustration on it. If dirty power is a real thing, must be measurable; right? We are talking about some pretty basic electrical/physics stuff, not heady psychoacoustics; right?)

 

Thanks in advance.

[sandyk]

Dirty power must be measurable; right?]

 

It can be readily seen through a suitably isolated (for safety reasons) C.R.O or the later Digital Oscilloscopes.

[jiminlogansquare]

Thanks for providing the first straight answer I have ever received to that question. If you or anyone else can point me to an article or a how-to on this, I would be in your debt.

 

And, could I hire an electrician to come in and run the appropriate test (and help me understand the results)?

[sandyk]

Thanks for providing the first straight answer I have ever received to that question. If you or anyone else can point me to an article or a how-to on this, I would be in your debt.

If you have access to a CRO you can get a rough idea just by using a cheap power transformer to look at the mains waveform. e.g.115 or 230 VAC primary winding as appropriate, to say 6V. You must use a transformer with separate windings.

Alex

[jiminlogansquare]

Alex, thanks. This is helpful. What exactly would I want to look for if I (or an electrician) performed that test? And can you tell me how the term "dirty power" (or "dirty AC") is defined by the experts? In the past, all I have gotten is something akin to the hand-waving responses of "juice cleansers" when I ask them specifically what they mean when they refer to "toxins."

[sandyk]

Alex, thanks. This is helpful. What exactly would I want to look for if I (or an electrician) performed that test? And can you tell me how the term "dirty power" (or "dirty AC") is defined by the experts? In the past, all I have gotten is something akin to the hand-waving responses of "juice cleansers" when I ask them specifically what they mean when they refer to "toxins."

 

If you know what a pure sine wave looks like, you may see gross distortion of one half of the waveform if the pollution is severe. Using the proper isolation methods instead of a simple transformer, you would also see plenty of HF rubbish if the mains are polluted at your place.

I am not qualified to give you deeper advice in this area, but quite a few qualified E.E. members should be able to do so.

I doubt that your typical electrician would have suitable expertise in this area.

 

Alex

[alfe]

Alex, thanks. This is helpful. What exactly would I want to look for if I (or an electrician) performed that test? And can you tell me how the term "dirty power" (or "dirty AC") is defined by the experts? In the past, all I have gotten is something akin to the hand-waving responses of "juice cleansers" when I ask them specifically what they mean when they refer to "toxins."

 

Power Line Noise

[tranz]

Thanks for providing the first straight answer I have ever received to that question. If you or anyone else can point me to an article or a how-to on this, I would be in your debt.

 

And, could I hire an electrician to come in and run the appropriate test (and help me understand the results)?

 

This website (eevblog) has a wealth of info and how to videos:

 

 

http://www.eevblog.com/forum/blog/eevblog-594-how-to-measure-power-supply-ripple-noise/

 

You can get a second hand Tektronix scope for a few hundred. But it is a bit of a learning curve.

 

An easier method is using this gadget:

 

http://www.audioprism.com/noisesniffer.html

 

This will, within a second, tell you if a power filter (also recommended) actually works, or how much noise a wallwart is throwing back into your AC circuit. It really helps pin point areas of improvement on your audio AC circuit.

[Paul R]

Apparently, there is not. Work the math. And even if there was, the component doesn't care. All it's looking for is the correct DC voltages it needs to operate. While it's possible for noise from a dirty AC line to get past the component's transformer and into the signal, a mere power cord isn't going to help with that. You need a good line filter if you have dirty AC.

 

 

Flat wrong there George, no apparently about it. John is right on this.

[wakibaki]

Power line noise is just another largely imaginary boogeyman that you can spend a lot of money on to protect yourself against despite the fact that you don't need it.

 

There's no reliable evidence RF that noise on power lines in any amounts normally experienced is audible at the outputs of audio systems. Loads of stories about the improvement people heard when the power conditioner was introduced, but very often no evidence of the presence of excessive noise in the first place.

 

If you are putting out noise in excessive amounts the police will come and shut you down. Conducted emissions are controlled by law in almost all countries. It's not like there's some kind of wild free-for-all going on.

 

It was determined some time ago that if electrical noise in the environment continued to rise that radio communications would become impossible. For this reason EMC compliance has been enforced almost worldwide. As a consequence noise has been controlled and radio communications continue to be possible. QED.

[Jabs1542]

Sort of but not quite.

 

Is the noise level so bad that things won't operate - of course not. But is there enough noise level to affect the sound of your system when to are squeezing the highest levels of quality you can muster - possibly.

 

I went from a power strip (no noise isolation) to a Monster Power power conditioning device and picked up a noticeable improvement. I have now replaced that with a PS Audio Perfect Wave power conditioner and picked up another audible improvement. The Perfect Wave has a slick digital oscilloscope built into it that can show you the wave going in, the wave going out, and the difference between the two. My home power has a little noise at the peaks of the sine wave and I guess it was enough to cause my source and control devices to work a little harder.

 

Note that I'm generally pretty skeptical over this stuff but I certainly heard a difference.

[davide256]

Why wait for Ebay... you can walk into a hardware store and buy the same quality based on what the pictures show of the cut cable end.

[davide256]

BTW power cables do matter, you don't have to spend an arm and a leg. Shunyata seems to get the most nods for entry level power cables. Expect more solidity in the bass from a power cable investment, I stocked up on the PS Audio Jewel cables when they were discontinued. The entry level Pangea cables tend to come loose from the wall socket. Didn't like the entry level Wireworld on any piece of gear, caused dynamic compression.

[gmgraves]

If you know what a pure sine wave looks like, you may see gross distortion of one half of the waveform if the pollution is severe. Using the proper isolation methods instead of a simple transformer, you would also see plenty of HF rubbish if the mains are polluted at your place.

I am not qualified to give you deeper advice in this area, but quite a few qualified E.E. members should be able to do so.

I doubt that your typical electrician would have suitable expertise in this area.

 

Alex

 

 

Powerline noise is real. Things like air conditioners, refrigerators, various computing devices can all contribute to noise on the AC. Some noise can even come in on the power line originating from sources outside the home, and yes it can get into one's audio signal (but on well designed components, it rarely does). However, noisy AC in and of itself is of no consequence. What is of consequence is whether or not this noise ends up on the audio component's DC output. If you're going to look at whether your power is clean or whether it's dirty and affecting the sound of your music, the place to look is at the output of the component's power supply. If you connect an AC coupled oscilloscope across your DC, and with it on it's most sensitive setting, see no noise, then no matter how dirty your AC is coming in to your component, be content that it's not affecting your sound. On the other hand, if you do see grunge on your DC supply to the component, be aware that an expensive line cord isn't going to help, but a good power conditioner might!

 

Alex is right. The average electrician is not equipped to test your mains for noise and it wouldn't mean anything, even if they could. Well designed components have had that aspect of the situation considered by the engineers who designed it. 50 - 60 Hz transformers, such as those used in audio components, have so much reactance at frequencies above 60 Hz, that they generally can't pass 99% of the high-frequency crap that typically comes in on a mains line. Any noise that gets into your sound is far more likely to be air-borne than AC - borne anyway.

[sandyk]

Well designed components have had that aspect of the situation considered by the engineers who designed it. 50 - 60 Hz transformers, such as those used in audio components, have so much reactance at frequencies above 60 Hz, that they generally can't pass 99% of the high-frequency crap that typically comes in on a mains line.

 

Nevertheless, John Swenson's recent designs use expensive r-core transformers because John has found that they do give a further improvement.

[One and a half]

Here's a paper outlining the most common noise makers on the AC line. Three classifications of single pulse, periodic pulse, and continuous pulse noise sources are measured.

Typically the amplitude of the noise is in mV, so for a 120V or even 230V, the effects of overvoltage are minimal, however the rate of rise of the noise with microseconds is the worrying part, enough to create an RF waveform.

 

Who among us has turned off a light switch and heard a thump, or click from the speaker? Occurs more than we want to.

 

Conducted noise such as the light switch is a pain, but readily fixed by replacing the light switch as the contacts have worn out over the years, so repairable.

 

AC Waveform distortion on the other hand affects transformers more than anything else. The frequencies that make up the distortion, have a negative influence on the flux pattern in that they oppose the flux created by the mains frequency being either 50 or 60Hz. So less of that the better, but I have seen power networks with 12% distortion and still running (albeit hot).

These lower frequencies (triplens) tend to resonate with PSUs in audio equipment as John Swenson measured and adding a different filter (a different power cable) altered these interactions.

 

We are not going to receive a perfect 0.0001% distortion sine wave with a single component, nor do we need to. Keeping out the pulse originators is the higher priority and avoiding other equipment from interfering with each other. EMC rules are often a joke, tell my wife EMC compliance exists when the microwave oven is on and cordless phone rings. It is not possible to have a conversation on that phone when the oven is working.

[gmgraves]

Nevertheless, John Swenson's recent designs use expensive r-core transformers because John has found that they do give a further improvement.

 

 

Nevertheless, I don't buy it. Sorry.

[gmgraves]

Who among us has turned off a light switch and heard a thump, or click from the speaker? Occurs more than we want to.

 

 

Are you trying to say that one of those "boutique" mains cable will solve that problem? Nothing on the amp end will solve that problem because it's a switching spike. If it annoys you, put a capacitor across the light switch.

[One and a half]

Are you trying to say that one of those "boutique" mains cable will solve that problem? Nothing on the amp end will solve that problem because it's a switching spike. If it annoys you, put a capacitor across the light switch.

 

You are reading beyond the post, I was identifying the sources of noise in a typical household.

[elcorso]

Nevertheless, John Swenson's recent designs use expensive r-core transformers because John has found that they do give a further improvement.

 

Hi Alex,

 

A lot of gear I know are under r-core transformers. The good ones are from the UK and some others are hand build for the same factory that manufactures the final product.

 

Roch