Sterophile new approach to cable measurements

[jneutron]

Are all input/output jacks isolated from the chassis? No. Unplug the leads and the loop goes away.

I do not understand your point here. I was speaking about a fully connected system. Please explain..

You may see his paper as full of holes but his practical experience is valid and his methods work.

As I stated:

In general, a very good and very practical paper, regardless of the holes I see

So as you can see, I certainly recommend the paper..

Re: Pin 1 issues- the common cure is lifting it or using anisolation transformer. A less common cure is using a good isolation transformer.

Bill addresses this also. Remember, his company makes isolation transformers. In one of his papers he remarks about somebody including lifting switches within amplifiers only to realize that doing so violated code. I think it was Bill, but it has been years since I read that..

Cheers, John

 

[highfigh]

And it was taken as you wrote it. Do not read anything nefarious in my segmentation of your sentence..I did this simply as they were independent entities to me and I split them to address them clearly and cleanly. I never intend to split to alter the perceived content of a poster...if you think that, you are incorrect and I apologize for the way it looked.

My own personal experience on the subject. I see their depth of experience, their background, their ad copy, their product line, and I do not see a match to a real understanding of it beyond simple hum.

My own personal experience on the subjects. I live with and deal with NEC, with UL approval (and lack of it), with ground loops in environments you would not believe, and I work to eliminate the loops and the sensitivities to such loops as part of my job. In seeing their "output", I do not see that which I would expect.

Very strange situation here...you blast their "output" with a knee jerk reaction (for lack of a better word on my part) but want to give them the benefit of the doubt with respect to technology...and I knee jerk them on their level of technology but give their "output" the benefit of the doubt..

This is very funny to me, as we both in essence are of the same mind..

Their output indicated only the one consultant. Quite honestly, I did not find any qualifications when I searched that guy for credentials. If I were a customer, that would concern me..

I remain skeptical of their findings as you do, but since there are certainly physics paths still there as error drivers, I remain open to the possibility that they may in the future present everything for peer review.

The chances of them finding the right guy is rather low. If they were to look up Tom Van Doren, their chances would be 100%. What impressed me about Tom was, over the course of two days, he made only two errors in technical presentation, and both errors were not significant for the topic at the time of presentation.

Cheers, John

Where it was split makes a difference- if you had split it at the comma, it wouldn't read the same, but OK.

I gave up on audio magazines in the early '80s, when I read the article about using a green magic marker on the edge of CDs to make the bass tighter. I read trade mags and if they include manufacturer written material, I take it with a grain of salt unless I see something that reinforces it. I blasted their output but it's so easy to find information and people who actually know how the technical details work that I can't imagine them not checking into these things.

The fact that he's in Rolla, MO helps me to make this point- that's not exactly the hub of American technology but he still makes his mark in that area.

If they don't research anything, it's even more disgraceful. Your conclusions come from reading their copy, but not talking with them, just like mine. Funny thing, neither of us trusts them.

"with ground loops in environments you would not believe:- why say that? I have seen some pretty complex systems and equipment, and I don't mean stereos in peoples' homes. Also, most of my friends are engineers of one kind or another.

 

[highfigh]

Understood.

If you go back to my post, you will see the following:


I repeat, we are discussing aftermarket power cords. To the best of my knowledge, there are no two prong aftermarket power cords...for the uninitiated, two prong cords can meet code if the unit is double insulated, like lots of simple power tools, toasters, clocks, radios, lamps.. But make sure the unit is listed and approved by an NRTL.

It would be great if someone posted the existance of any two prong aftermarket cords, I'd be interested in looking at them..


Cheers, John

"To the best of my knowledge, there are no two prong aftermarket power cords"

C-17 and C-18 cords have no third pin. The image is of the rear of a Denon AVR-5308CI receiver.

 

[jneutron]

"To the best of my knowledge, there are no two prong aftermarket power cords"

C-17 and C-18 cords have no third pin.

Who sells them? Any link? Do they meet code? Are they listed NRTL?

Understand, the lack of a bonded safety ground on a unit certainly doesn't eliminate ground loop sensitivity. It does however, alter the frequency transfer characteristics of the sensitivity. In cases such as that, the only thing we'd hear as a result of line noise would be clicks and buzz. Once the haversines get involved, the higher odd order harmonics would show up... But again, the system audible output confounds discovery, and FFT analysis may not show the interchannel phase shifts in a reasonable fashion.



Thanks, John

ps.. a google of "C-17" produced the boeing Globemaster III. I never realized they used a two prong line cord for that airplane. That's a honkin long extension cord, eh??

 

[gene]

Is there any chance of you, as an engineer, challenging them to prove their claims and publishing the findings? Maybe this could take place at CES or CEDIA, in a controlled environment, with people who are familiar with critical listening as observers. If their claims are to be believed, they should be willing to prove it to more people in a short time. If it works, great. If not, they should have the cajones to print it in their rag.

I doubt they'd be willing to do it, though.

To do that would only give them what they want. More attention! You can't reason with people like this just like you can't reason with someone who denies evolution, LOL

 

[highfigh]

I do not understand your point here. I was speaking about a fully connected system. Please explain..

As I stated:


So as you can see, I certainly recommend the paper..


Bill addresses this also. Remember, his company makes isolation transformers. In one of his papers he remarks about somebody including lifting switches within amplifiers only to realize that doing so violated code. I think it was Bill, but it has been years since I read that..

Cheers, John

I did car audio for a while and at CES (mid '80s), Bill spoke about noise problems and ground loops in car audio systems and when I went to CEDIA in '05, he spoke again. Same info, somewhat different issue (DC ground lifts affecting the audio), same basic problem. Too bad the others I went with had no clue about what he was saying.

The lifting switch wasn't for the power connections, it was for the mic/line inputs but the code situation sounds familiar.

As you posted, "Star grounding" has to do with zero potential difference, as opposed to a physical appearance. I have seen and read that many people are confused by this and I think more should be devoted to this topic.

 

[highfigh]

To do that would only give them what they want. More attention! You can't reason with people like this just like you can't reason with someone who denies evolution, LOL

As long as their claims are debunked, they can have all the attention they want. I have no problem with that as long as the truth comes out of it. Too many questions exist to leave this alone.

Maybe the test could be repeated in a dark alley in a bad part of town.

 

[jneutron]

The lifting switch wasn't for the power connections, it was for the mic/line inputs but the code situation sounds familiar.

That is what I was referring to, the lift switch pulls pin 1 off ground. Not to code...

As you posted, "Star grounding" has to do with zero potential difference, as opposed to a physical appearance. I have seen and read that many people are confused by this and I think more should be devoted to this topic.

Actually, if you use a little imagination, star grounding does kinda fit the physical appearance.

My concern is always the fact that all it takes is one lousy star ground wire bandying about some hf garbage willy-nilly to spoil the neighborhood. Then the assumption that all the other wires are seeing the same potential is incorrect.

At the absolute best, there can only be 3 physical connections to a point that can be considered orthogonal..and that is a specific physical geometry with the 3 wires as axis of a 3-d coordinate system..think of a cube balanced on a point, the three edges leave the point at 90 degrees to each other, so none of the edges create magnetic fields which are intercepted by the other two.

Sometimes one has to be creative...

Hey, you didn't answer my question. Are there aftermarket vendors who sell two prong upgrade cords? What are C-17 and C-18?

and ps...yes, the topic can be confusing to the uninitiated.

Cheers, John

 

[highfigh]

That is what I was referring to, the lift switch pulls pin 1 off ground. Not to code...

Actually, if you use a little imagination, star grounding does kinda fit the physical appearance.

My concern is always the fact that all it takes is one lousy star ground wire bandying about some hf garbage willy-nilly to spoil the neighborhood. Then the assumption that all the other wires are seeing the same potential is incorrect.

At the absolute best, there can only be 3 physical connections to a point that can be considered orthogonal..and that is a specific physical geometry with the 3 wires as axis of a 3-d coordinate system..think of a cube balanced on a point, the three edges leave the point at 90 degrees to each other, so none of the edges create magnetic fields which are intercepted by the other two.

Sometimes one has to be creative...

Hey, you didn't answer my question. Are there aftermarket vendors who sell two prong upgrade cords? What are C-17 and C-18?

and ps...yes, the topic can be confusing to the uninitiated.

Cheers, John

If someone drew a star grounded system with the length of the rays as a representation of the potential, I agree. The HF issue is why I could see more shielded power cords in the future as long as the correct orientation is used WRT to electrostatic shielding. I still hate RCA cables for the inability to properly shield the signal.

The right hand and left hand rules could be used to allude to orthogonal. Also, I did 6 years of drafting and we used orthogonal projection a lot.

I usually tell people who are confused about star grounding, especially when it was in a vehicle, that it's not that everything needs to be grounded at the same physical location, but that they all have to measure zero resistance from the reference point. A car body is a pretty bad ground plane and connecting a head unit's ground wire to the dash harness is a sure way to end up listening through the noise to hear the music.

RE: the IEC plugs- here's a wiki link. Scroll down and you'll see C17 and C18.
http://en.wikipedia.org/wiki/IEC_connector

 

[mtrycrafts]

Is there any chance of you, as an engineer, challenging them to prove their claims and publishing the findings? Maybe this could take place at CES or CEDIA, in a controlled environment, with people who are familiar with critical listening as observers. If their claims are to be believed, they should be willing to prove it to more people in a short time. If it works, great. If not, they should have the cajones to print it in their rag.

I doubt they'd be willing to do it, though.

One of the problem is that it also needs to be under DBT protocol. That is not well accepted by many at those places

 

[highfigh]

One of the problem is that it also needs to be under DBT protocol. That is not well accepted by many at those places

Too bad. We don't like claims that can't be substantiated and they don't like DBT. They don't doDBT but we have to be subjected to their claims.

I say we tie them down and force them to do it the right way. If we need to get them liquored up, so be it.

 

[jneutron]

If someone drew a star grounded system with the length of the rays as a representation of the potential, I agree. The HF issue is why I could see more shielded power cords in the future as long as the correct orientation is used WRT to electrostatic shielding.

For this entire thread, I have not been considering electrostatic shielding.
The impedance of the system is far below 377 ohms, which is free space impedance. Because it is so far below 377 ohms, the major source of induced noise will be magnetic, not electric.
In the audio range, shield materials are almost useless. Blame skin depth for that.
What needs to be considered is the loop topology..

I still hate RCA cables for the inability to properly shield the signal.

It's not the shield, it's the loop. As long as the cable retains a cylindrical cross section, it will be impervious to all far field radiation, and it will be impervious to all near field dipole radiation. High gradient fields, such as that when it passes by an E-core transformer edge, that is a special condition which coax cannot fully shield. (it's a field map thing...)

The right hand and left hand rules could be used to allude to orthogonal.

LOL.. we use the Right hand rule for everything except e-beam particle accelerators, there we use Left hand..

Also, I did 6 years of drafting and we used orthogonal projection a lot.

That is a good data point. It lets me know how descriptive I can get...most people go "deer in the headlights" when I mention orthogonal set. A cat-5 cable for example, has 4 orthogonal twisted pairs. This is done via 4 different twist pitches. Within a chassis, orthogonality requires either twist pitch games, or right angles.

RE: the IEC plugs- here's a wiki link. Scroll down and you'll see C17 and C18.
http://en.wikipedia.org/wiki/IEC_connector

Thanks for the link.

It must be noted that one can use a c-13 in place of a c-17, but not the reverse.
A C-17 is intended for a class 2 appliance, which by definition is one with no bonded safety ground, usually two layers of insulation (double insulated), and designed such that no one internal fault can result in an external surface being energized such that fatalities can occur.

A C-13 is for the bonded grounded external surface, class 1..

Since you did not answer the question, can I assume that nobody makes an aftermarket hi-falutin C-17 cord?

Cheers, John

 

[jneutron]

One of the problem is that it also needs to be under DBT protocol. That is not well accepted by many at those places

No. Such is not the case here.

Remember, they were claiming bit error measurements. NOT audibility per se.

They of course intend for all to take the audibility improvement as a given as the error rate is lower, but you are correct in that an audibility claim would require an audibility test methodology..

Cheers, John

 

[highfigh]

Since you did not answer the question, can I assume that nobody makes an aftermarket hi-falutin C-17 cord?

Cheers, John

I hope not but I think a huge power cord with pretty braiding over it on my toaster would be cool!

I have an idea- when people come here to show new info about cable that goes against all logic, how about if we post links to actual physics and IEEE data on the subject? That way, the science can be used to make the choice of "Should I buy this cable?".

 

[jneutron]

I hope not but I think a huge power cord with pretty braiding over it on my toaster would be cool!

Ah, but it'd have to meet the temp requirements...

I have an idea- when people come here to show new info about cable that goes against all logic, how about if we post links to actual physics and IEEE data on the subject? That way, the science can be used to make the choice of "Should I buy this cable?".

I agree 100%.

But if I recall correctly, Nordost didn't come here showing anything. They presented some kind of actual measurements of some kind of actual error, and stated that some kind of actual wire or cord or whatever changed the actual measurement of error rate in some kind of actual digital signal.

Of course, some kind of.. had to be used in lieu of actual data, which was not presented.

This thread was all about people here blasting the voodoo science and snake oil they perceived from a presentation given elsewhere.

Had they presented something which was inaccurate, I'd be the first in line blasting them. But they didn't.. Just fluff, no stuff.

Cheers, John

 

[jneutron]

The fact that he's in Rolla, MO (Tom Van Doren:edit me) helps me to make this point- that's not exactly the hub of American technology but he still makes his mark in that area.

Ah, but you should take his course. He presents incredibly useful information, and shows everybody things that they either did not know, were never taught, or never considered. You would be suprised how many simple rules are violated when it comes to Electromagnetic Compatibility.

His list of customers btw, includes all the big companies.

If they don't research anything, it's even more disgraceful. Your conclusions come from reading their copy, but not talking with them, just like mine. Funny thing, neither of us trusts them.

I trust them. I believe they have presented all that they know. We all agree that they did not present much.

"with ground loops in environments you would not believe:- why say that? I have seen some pretty complex systems and equipment, and I don't mean stereos in peoples' homes.

A "toy" 800 meters in diameter, uses 5 Megawatts at 500mhz, 900 switchmode supplies ranging from 5 amps 20Khz sine to 400 amps 1600 volts dc, and 360 capacitive pickup transducer quad sets with 600 volt peak and 500 mhz rep rates and 1 microvolt differential resolution from DC to about 50 Khz..

I am one of the cogs in this mess..

What I enjoy is the fact that high end audio stuff like what we speak of (ground loops), actually is just like the stuff I do for work.

Also, most of my friends are engineers of one kind or another.

Friends? What is that?

Cheers, John

 

[highfigh]

Ah, but it'd have to meet the temp requirements...


I agree 100%.

But if I recall correctly, Nordost didn't come here showing anything. They presented some kind of actual measurements of some kind of actual error, and stated that some kind of actual wire or cord or whatever changed the actual measurement of error rate in some kind of actual digital signal.

Of course, some kind of.. had to be used in lieu of actual data, which was not presented.

This thread was all about people here blasting the voodoo science and snake oil they perceived from a presentation given elsewhere.

Had they presented something which was inaccurate, I'd be the first in line blasting them. But they didn't.. Just fluff, no stuff.

Cheers, John

"Some kind of" is an extremely scientific term. Never doubt anyone who uses it in some kind of sentence.

 

[highfigh]

Ah, but you should take his course. He presents incredibly useful information, and shows everybody things that they either did not know, were never taught, or never considered. You would be suprised how many simple rules are violated when it comes to Electromagnetic Compatibility.

His list of customers btw, includes all the big companies.

I trust them. I believe they have presented all that they know. We all agree that they did not present much.


A "toy" 800 meters in diameter, uses 5 Megawatts at 500mhz, 900 switchmode supplies ranging from 5 amps 20Khz sine to 400 amps 1600 volts dc, and 360 capacitive pickup transducer quad sets with 600 volt peak and 500 mhz rep rates and 1 microvolt differential resolution from DC to about 50 Khz..

I am one of the cogs in this mess..

What I enjoy is the fact that high end audio stuff like what we speak of (ground loops), actually is just like the stuff I do for work.


Friends? What is that?

Cheers, John

Is that in Batavia?

 

[jneutron]

"Some kind of" is an extremely scientific term.

Yah, tell me about it.. The alternative word describing the level of scientific acumen presented...doesn't make it through the bot-censor..

Even one fact would have been nice. But then again, they are in the business to make money, so any perceived advantage or tech voodoo is what they need to keep food on the table.

Nobody attacks the car companies for this type of advertisements, the makeup companies..but high end audio seems to bring out the best and the worst..go figure. I think it's because many of them flaunt physics so much, it's just normal now to doubt and attack..

Never doubt anyone who uses it in some kind of sentence.

Good one..

Is that in Batavia?

No. Tis a different one.

Ah, btw...IEEE-1050 begins to discuss the issues surrounding ground loops, but not far enough. They do discuss "agressor" and "victim" circuits a tad.

Cheers, John