| AudioREVIEW's Forum Archives - Cables & Interconnects |
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|   Jneutron , please come clean on the Power Cord issue. | Tony_Montana
Nov 3, 2003 8:16 PM | | Hey Zorro
This was your response to Woodman's post that PoweCords don't make alot of differences on how an amplifier sound:
<a href="/crforum?14@@.efa002d/39">jneutron "Sure doesn't take much to get a COOL IT" 11/1/03 4:20pm</a>
You wrote in your post:
"So, it is not the distance, it's the loop formed by the wall outlet/pre cord/IC/amp cord, and the current haversines and audio currents imposed on the amp cord, to be loop intercepted at the amp input end..along with the PC twist pitch..the source cord pitch, the insulation thickness of each (spacing conductors), and the resistivity of the loop along with how it's parsed...it's an interesting problem..but certainly a testable one..not requiring magic or unproven suppositions.." Jn
To tell you the truth, I didn't understand half that paragraph you wrote, and the other half is still murky :)
My main question is wouldn't the power supply filtering break the loop that you are talking about, and how would using a better PC effect the over all sound quality of an amplifier?
And please comment in not too technical terms. I want to undrestand it :) |
| Hi tony | jneutron
Nov 4, 2003 5:18 AM | | At home, I have a 5.1 surround system. With that is a powered subwoofer..When I turn on the hall light (nearby), there is a loud pop from the sub. When the forced air blower turns on, again, a loud pop.
This is not because of the supply inadequacy of the sub, that design in good enough....the pop is coming in with the IC..
My sub forms a ground loop with the outlet and receiver... each has a chassis ground connected to the wall outlet ground, and the IC completes the loop. disconnect the IC, the pop goes away..unplug the receiver, same thing..
So, the loop is picking up the transient currents on the circuit..because of the IC and powercord completing the loop.
Now, what parameters determine the level of that pop? The loop formed has a total resistance, and the amount of pop there is proportional to the shield resistance part of that loop. The lower the shield resistance, the lower the level..The pc does the same, but the other way..the lower it's ground resistance, the higher the pop.
The loop is responsible for the level also, make the loop bigger, the pop gets bigger..smaller, pop goes down.
Sometimes, the pickup is so big that people are forced to remove the safety ground to stop it..(not recommended ever).
So far, all I've talked about is external things causing the noise..what about a large power amp..when it draws, it uses the line also..it is possible that the setup can be sensitive to that current and make a hum out of it, but if it's the power amp that is causing the hum...well, the hum is big only when the amp is working hard..in other words, the audio signal will mask (for the most part) the hum the loop is picking up.
You might hear it if you have a cd that makes a 60 or 120 hz signal, as it would make the signal beat (although it may be masked because of relative level. Or, you could use a spectrum analyzer to look for it on the output.
Various power cord constructions can change the sensitivity of the system to the current from the power amp, because of the ground size, the ground contact resistance, and even the way the hot/neutral are twisted around it. People would perceive that change (assuming of course, that the system has that sensitivity).
So, the PC can make a difference, but not because of magic, and not because it's making it past the power supply. This can be tested for. It just requires testing the system with all the normal components in place and running hard. (when you plug in a source generator and a spectrum analyzer to the system, you open the loop up, and the sensitivity goes away..so each component may read very good.
In my mobile apps, I make sure the front end source rack is plugged into the same outlet as the amp it is driving..that at least gets rid of external sensitivities. My applications do not care if the system is picking up some hum from the amp draw, but I could see critical listening finding it..
Oh, almost forgot..if the power amp allows any signal remnants into the line, because of loop coupling within the supply, that will end up as ic shield currents, getting into the input..In mil apps, they sometimes specify the amount of "bleed" into the line that is allowed..I don't think home audio has the same requirements. But if that happens, again, the PC, IC, and even how the cords are draped will have an effect.
Cheers, John |
| But John, in spite of all your well informed babble... | RADAR O_Riley
Nov 4, 2003 5:24 PM | | ... the fact remains that 99.9999% of all the audiophile hype and mythology surrounding power cords is absolute bullshit, and you know it. You play very funny games for such a smart fellow, IMHO. You sound more like your buddy Jon than any real engineer I've ever met. ;-)
R.O. |
| Now, now - let's play nice. | pctower
Nov 4, 2003 5:50 PM | | b ... the fact remains that 99.9999% of all the audiophile hype and mythology surrounding power cords is absolute bullshit, and you know it.
I've never seen John even come close to trying to defend hype or mythology.
b You sound more like your buddy Jon than any real engineer I've ever met. ;-)
John has been far more precise than anyone else I've seen in describing in detail where he disagrees with Jon and where he agrees, all supported by in-depth technical analysis.
In this case, John had responded to an unconidtional statement about power cords in a thread below, and up here he was asked to state his position. He did so in a very straight-forward way and without in any way endorsing any claim of any cable company.
So what's the big deal? |
| It's the silly games he plays. Read the post again. (nt) | RADAR O_Riley
Nov 4, 2003 6:24 PM | | (nt)= no text. |
| I'm afraid I'm not seeing the "silly games" you speak of. | jneutron
Nov 5, 2003 7:06 AM | | I went back and re-read my post several times..and still, I have no idea what you are talking about..as far as I can tell, everything I have stated is known e/m theory and known experience, and meets the first rule of a hypothesis, which is testability..
Would you please elaborate?
Cheers, John |
| Do you understand your topic? ... | RADAR O_Riley
Nov 5, 2003 8:54 PM | | ... If you understand it, and I know that you do, you can explain it in terms others won't stumble over. You love to baffle with BS as much as your buddy Jon. The only difference is that you're BS is based in reality while his is all in his mind. If you don't realize that you're just playing games with others and trying to impress them with your superior intelligence you are most likely missing something. I don't think anyone else other than Phil has failed to notice, but of course I stand to be corrected if that's wrong.
You make the simple complex to impress others. That's a game John, a very silly game IMNO.
Are you going to now claim that the time you spend talking to Jon is something that you actually expect to be productive? If that isn't a game, a silly game, then you're seriously expecting to learn something form the Cult Crazies. If that's the case, that's probably where you should be posting. I am no longer impressed by your posturing..
I see no reason for you to be concerned about what I think of your posts and games. They're yours to play as you see fit.
R.O. |
| Absolutely.. | jneutron
Nov 6, 2003 6:26 AM | | As you point out (or, at least you have tried to), the topic and error mechanism I have pointed out, are rather subtle..
Your desire to attribute to me the type of game playing crap you have posted here in the past (remember the Jon Risch is insane BS you kept on hammering us with?), is simply an indicator of the type of attitude you choose to bring to the table here..
You are correct, in that I am not concerned with what you think in that regard..I would, however, be concerned if you actually decided to discuss the topic in this thread..
ROR: ""You make the simple complex to impress others. That's a game John, a very silly game IMNO.""
If that were indeed the case, then your criticism would be valid.. You have, however, misread the whole ball of wax, here..
ROR: ""I am no longer impressed by your posturing..""
You have shown that you are the one posturing here..
I'm trying to discuss how cables may affect sound..If you hae anything to add to the thread, I'd be happy to read it.. Otherwise, what is your purpose here..
Your posting is reminiscent of John Curl posts..within the entire thing, nothing technical was discussed..just slamming..
I have seen better from you..
You seem to have a lot to learn from Tony and others..If they don't understand, whether it is their lack of knowledge, my lack of understanding, or my ineptness at explaining...they ask questions, or point out my errors..why did you react the way you did?
Cheers, John |
| Oh...I just now put it together | jneutron
Nov 6, 2003 7:52 AM | | You consider Jon Risch to be your sworn mortal enemy..
And you now vent because I have the nerve to even discuss any topic with him over at AA.
It is now clear to me..you are attacking me because I do not take up your cause..
Well, Radar...you are entitled to your opinion..you are entitled to your wars..you are always free to do as you wish..
But do not expect me to smash anyone simply because you do not like them.. I have had disputes with him, but I take them on a one at a time basis when necessary. From what I recall, you have a long history with him, so your feelings may indeed be justified..
But now you take it out on others..
Cheers, John |
| Do you understand your topic? ... | pctower
Nov 6, 2003 6:53 AM | | b I don't think anyone else other than Phil has failed to notice, but of course I stand to be corrected if that's wrong.
In marriage counseling (my 26 years and counting is testament to my familiarity with that subject), that's known as employing an army. Rather than allow your own words to stand on their own, you bring in an entire "army" on your side by claiming that "everyone else" agrees with you.
You have employed that same tactic in dealing with me. |
| Now, now - let's play fair. | skeptic
Nov 5, 2003 6:40 AM | | "I've never seen John even come close to trying to defend hype or mythology."
Defend it? He is the inventor of it.
When I exposed his countless bullshit rationales for his cable idiocy, he stopped posting here, not after I called him a Nazi mind control gestapo for his censorship at CA. I beat him on every one of his arguements.
Case in point, digital jitter. When he started this claptrap, I pointed out that the jitter caused by the mechanical wow and flutter of the disc turntable was orders of magnitude greater than his so called digital jitter caused by wires and that it didn't matter because it all got reclocked and buffered anyway. Then he went on a long diatribe about fast jitter versus slow jitter and babbled on on and on senselessly. Then he left. He knew his "hype and mythology" wouldn't go unchallenged at least here when he can't censor the truth from people smarter than he is. |
| Wrong Bubba | pctower
Nov 5, 2003 6:45 AM | | I was referring to "John" (aka jneutron), not "Jon" (aka Jon Risch). |
| Ummm..skep.. | jneutron
Nov 5, 2003 6:46 AM | | John is me...jneutron..
Jon is not me, it is Jon Risch..
You are confusing the two..
Cheers, John (aka jneutron, sully at diy)
PS..phil..maybe you should call me John E so others are not confused.. |
| WHOA! | FLZapped
Nov 5, 2003 9:46 AM | | Dude, you have two different people mixed together here!!!!
-Bruce |
| Hi Bruce.. | jneutron
Nov 5, 2003 10:03 AM | | I have you to thank for this recent flurry of rudeness heaped upon me....c'mon over, John...have a good time, John...we all miss ya, John...have a party, John (Bruce Willis in the duct, with a lighter... Diehard 1) :-)
Honestly, it all confuses me...At CA, I am called a "nefarious naysayer", with rudeness heaped upon me by Risch, Curl, Hansen, etc...While, here, I am hit with "yiddish yaysayer" (I couldn't think of a good "y" word to go with yaysayer).
Maybe Radar, Woodman, Curl, Risch, Hansen should all get together and figure out what they want to call me, so they can at least be consistent in what they wish to attribute to me..and figure out what side of the fence I'm supposed to be on..of course, "A-hole" would certainly be consistent..:-)
Woodman..perhaps a link for you to peruse would make some things a wee bit clearer..read the thread to it's end..
http://www.audioasylum.com/audio/cables/messages/84231.html
Cheers, John |
| Glad to be of service....... | FLZapped
Nov 5, 2003 10:17 AM | | Hey, I can't help if these guys got up on the wrong side of the bed.....maybe they miss JR and used you as a surrogate?
Perhaps you should change your first name to William or Ethan, so something.
So now I have some questions.
I understand you're trying to develop all these models for something you're working on where you believe skin depth problems will arise and need to impress the big-wigs with it so you can get more funding. ;~)
But in all seriousness, do they amount to a hill of (audible)beans for the average person - or even terminally ill audiophile who is deep in the throws of Audio Nervana Nervousa?
Even rf guys don't worry too much about it. Besides, being lazy(in my opinion), they developed alternate formulas which deal with the problem indirectly and simply......
Having said all that, I really think if you started a fresh thread, this would still lead to some interesting discussions. (no prediction to the accuracy of that statement, one must assume it is just a scientific wild-assed guess, got it?) Especially if it was actually related to, say, speaker cables........Not like this is an audio board or anything, of course.
So, are you guys gonna win this whole debate on string theory, or are ya gonna let CERN beat ya to it?????(Hello, left field)
Regards,
Bruce |
| Glad to be of service....... | jneutron
Nov 5, 2003 10:30 AM | | Hmmm..Ethan..
Good morning, MR. Hunt..the man you are looking at is...
Don't know if skin is audible..But it's a really cool subject, and I really, really, get into it from an e/m point of view. The fact that it is of paramount importance with superconductors is great, as that ties to what I do daily..The fact that it may or may not have any audio effects is just another facet, and keeps me very interested in it from two directions..
RF guys aren't lazy..it's just that the depths are so small compared to diameter, that the exponentials are dead nuts on.
Another thread? Yep, when I've cleaned up the software..I wrote it origionally for magnet field analysis, so all field vectors were calculated w/r to field center, giving radial and azimuthal field components, with magnitude as sqr of sum of squares.. That turned out to be a real PITA for displaying the field magnitude and direction, so I have just re-coded the field formulas to produce simple x-y magnitudes. (still trying to get yellow and green into the display), with field map lines.
String theory...I missed part three..damn..
Going there in January to help them test the next magnet type we delivered. Gonna hafta figure out how to stall them so we can catch up...Maybe I'll bring some special power cords over...that'll slow em...
Cheers, John |
| thought so. | FLZapped
Nov 5, 2003 12:39 PM | | Ah such fun. Well, guess I need to get back to my radio assisted computers here, although this week it's been writing field bulletins, how exciting.
-Bruce |
| Sorry I got you mixed up with somebody else (nt) | skeptic
Nov 5, 2003 11:04 AM | | |
| You need to grovel more than that..... | FLZapped
Nov 5, 2003 12:36 PM | | ...as it wasn't just anybody you mixed him up with *grin*
-Bruce |
| My thoughts in a nutshell, RADARman nt | woodman
Nov 4, 2003 5:53 PM | | |
| Hi Woodman. | RADAR O_Riley
Nov 4, 2003 6:29 PM | | Phil is having trouble understanding what was said, but I can see that it wasn't that unclear. You obviously understood.
;-)
R.O. |
| Hi Woodman. | pctower
Nov 5, 2003 6:52 AM | | b Phil is having trouble understanding what was said, but I can see that it wasn't that unclear. You obviously understood.
I'm having no problem understanding what you said. You didn't like him talking about that particular subject and rather than respond to specific points he made (as Tony Montana did in a very professional way), you chose the route of a covert attack in your references: "well informed babble" and "You sound more like your buddy Jon than any real engineer I've ever met".
I can see why you might think John doesn't sound to you like a "real engineer", as your covert personal attack is classic John Curl. Perhaps Curl is the kind of engineer your used to meeting.
BTW, you also chose to take a very specific post about a narrow issue dealing with cable and treat the poster as if he was promoting every snake oil claim that had ever been made about cables. But, then again, I'm accustomed to that type of approach from you. |
| Like I said Phil, you totally failed to understand, but ... | RADAR O_Riley
Nov 5, 2003 9:00 PM | | ... Woodman had no problem.
By the way, you not only misunderstood entirely, you are also full of crap. The FACT OF THE MATTER is that I agree with what John said, but not the way he said it. So you see Phil, you really didn't have a clue, but you still shot off your mough. A-hole Phil, that's you tonight alright. Nice job.
R.O. |
| Speaking of clueless | pctower
Nov 6, 2003 5:55 AM | | b The FACT OF THE MATTER is that I agree with what John said, but not the way he said it. So you see Phil, you really didn't have a clue, but you still shot off your mough.
I didn't say, or imply, that you disagreed with him. I said you didn't like him talking about that subject, which I think is closer to the truth than that you think he makes things too complicated. I said you could respond to his specific points. If you really wanted to be clear about your post you could have criticized him for making things too complicated and pointed out how he could have made it simpler, rather than compare him to Jon and make obtuse comments about "his funny games" and informed babble.
In my opinion you completely contradict yourself. You complaint about the deficiencies in our educational system (although Ive never heard you describe anything you are doing to help rectify those deficiencies), and you complaint about the pseudo-science that permeates the audio boards. Then when someone like John comes along and attempts to raise the typically inane discussions that occur on audio boards to a rational and informed level and takes to task those very people who are promulgating the pseudo-science you complain about, and does so point-by-point in far more detail and with far greater persistence that you ever do, you broadside him with covert criticisms, and complain that hes just playing games with others and trying to impress them with [his] superior intelligence.
So, obviously, one has to walk a very tight rope with you. Ones questions have to be very carefully and narrowly crafted or they are labeled stupid, as you have labeled mine, but on the other hand one cant display very much actual technical knowledge, or one gets accused of just trying to show off his intelligence, as you have accused John of doing.
If making things too complicated is what makes John like Jon, I'd sure like to see you point to an example of Jon making things too complicated. Seems to me Jon's problem is that he often treats unsupported speculation as truth and jumps to simple conclusions without doing that complicated kind of rational and fact-based analysis that John does.
BTW, I know what an "A-hole" is (Im very accustomed to seeing that kind of language employed on audio boards by John Curl), but what's a "mough"? |
| Hi Woodman.. | jneutron
Nov 5, 2003 9:32 AM | | It would be nice if you would also explain why you have come out gun's ablazin..
I present a hypothesis, based on observation and understanding, and present a model which is fully testable..No dbt's, no opinions, no snake oil...but, something that can be tested using simple equipment..and nothing that violates known EE or physics..in response to your post that "pc's never, ever, under any circumstance, will ever have an effect on a system". Never.....ever..
Since I have in fact, experienced that with my mobile rig, my HT system, and all the time in work..I worked to understand what was happening, in order to make my work and mobile systems impervious to the effect..btw..not a "magical, soundstage effect"in my case, just transient garbage.
Conjecture that a PC could in any way affect the sound "stage", or "blur", or whatever, by me, was (as I made quite clear), conjecture (you know, the audio bleed through statement), and that SHOULD that actually happen, the loop is why, and more importantly, a way can be developed to test for it.
My post was to make clear what I think, so that others could understand what I was saying, that the loop is what I'm calling the problem...
How many people have just replaced a power cord (on say, a phono preamp)and claimed "better, less filling"...only to find that when a test analyzer was connected to the preamp, nothing measureable changed..leading the tester to think "looney tunes here".. the measurement setup ignored the loop I speak of..and bench measurements wouldn't duplicate the loop, just like bench measurements of my sub by itself would show clearly that the unit is not susceptible to line transients..nor the dvd/receiver unit.
Your attitude, like Radar's, confuses me..
Please explain..
Cheers, John |
| I have never claimed it was well informed....:-). | jneutron
Nov 5, 2003 6:09 AM | | ROR: "" the fact remains that 99.9999% of all the audiophile hype and mythology surrounding power cords is absolute bullshit, and you know it.;-""
I've not stated otherwise..
ROR: ""You play very funny games for such a smart fellow, IMHO. You sound more like your buddy Jon than any real engineer I've ever met. ""
There is one significant difference..
I have tied a really visible (audible, actually) event (the loud pops my light switch gives my system) to a specific e/m theory.. How many people have heard this? I would suspect everybody on the planet..
And, my posting details a hypothesis, a real e/m explanation, what is causing it, how to eliminate it, what the ramifications can be if the effect further on down (audio bleed through into the line cord), why PSRR and line filtering doesn't stop the effect.
But, the most important thing by far: I have provided a hypothesis that is TESTABLE. I have not claimed that the effect is so subtle, that you need a "really really good system with very high resolving power".
To test my hypo, one needs to consider how to keep that "nefarious" loop intact, while trying to identify the signals I hypothesize..
My post does not include hash, blur, grain boundaries, motor generator, piezo, burn in, plating, surface finish, skin theory, lifters, stranding, or any other "interesting" things.
It is based entirely on maxwell's equations..
So, I do not understand what you were trying to convey in your post..I am confused as to whether you were just trying for humor, or if you did not understand what I explained..In either case, I apologize,,for nut getting the humor, or for an inadequate explanation..
Cheers, John |
| To test the theory | skeptic
Nov 5, 2003 8:46 AM | | Break the ground loop by removing one of the green ground wires from one but not both units. Try reconnecting and removing the green ground wire to the other unit. Try removing both green wires and see what happens. Really want to test it? Power the units on batteries using inverters or a UPS but connect both green ground wires to the house distribution as always. If your hypothesis is correct, you know what the outcomes will be.
Between my experience and my training including countless vendor seminars, I think I have encountered every form of electrical power disturbance in the known universe. Transverse and common mode noise, sags, dips, peaks, spikes, surges and harmonics, yes lots and lots of harmonics. I've installed many systems to deal with them and seen many others which were crazy. I've written installation and test procedures for isolated ground networks but in all my years niether I nor any electrician or other electrical engineer I've met ever encountered a situtaton where someone said "we had a problem but when we installed an isolated ground system and eliminated the ground loop, the problem went away." Not only are most of them installed incorrectly, but some of them were downright dangerous and in violation of NEC 250. However, I admit that signal cables coming into a building often are patched to a patch bay having ground equalization and lightening protection for the building.
BTW, beyond the Telephone standard of gound planes and ground windows, Sperry used a copper foil sheet taped to the ground floor concrete slab on grade with braided conductors for a pure signal ground. Their explanation was different from mine which was that it formed one plate of a large capacitor to earth ground (not to mention all of the grounded steel in the concrete.) Some scientists liked "eupher" or chemical well grounds with ground rods in amonia salt solutions right in the earth. Another is the ring ground burried loop for data centers, hundreds of feet long with radial ground leads brought in that are cad welded to the burried ring. Do you think they could have gotten away with just replacing the power cords instead? |
| I did so only for my sub.. | jneutron
Nov 5, 2003 8:59 AM | | As posted elsewhere on this thread..
Also tried using a hand held cd player with AA batteries..no pop with just that connected to sub either..
SK: ""Do you think they could have gotten away with just replacing the power cords instead?""
If only it were that easy..Some of the hype I've seen would claim that, though..
Cheers, John |
| I did so only for my sub.. | skeptic
Nov 5, 2003 9:16 AM | | And some of the hype claims it will cure cancer too. Or just short of it. |
| Most problems you mentioned is with IC, not PC. | Tony_Montana
Nov 4, 2003 9:09 PM | | Hey John
I see the loop [problem] you were talking about. You said that most problem causing the hum in a system is the shield problem, and I agree with that statement. In matter of fact, I talked about this problem while back:
<a href="/crforum?50@@.ef9b16a">Tony_Montana "Double shielded interconnects can reduce ground loops." 5/19/03 2:31pm</a>
<img src="http://www.epanorama.net/documents/groundloop/gndloop.gif">
.
As you can see from above picture, IC's shielding resistance causes loop resistance to rise, given grounds uneven potential that is most causes of hums. The popping sound as you mentioned is caused by transient current and sometimes it is hard to avoid it.
But now we get to murky waters :)
You wrote:"The pc does the same, but the other way..the lower it's ground resistance, the higher the pop." Jn
How can one lower pc resistance given that most audio component's pc don't have ground connection, or the ground connection is a thick 18 gauge wire which have practically zero resistance?
You also wrote:"Various power cord constructions can change the sensitivity of the system to the current from the power amp, because of the ground size, the ground contact resistance, and even the way the hot/neutral are twisted around it." Jn
Again, this looks like apply only to PCs that have three prongs. What about two prongs PC that 90% of amplifier uses. Would we run cross the same problems with two prong PC?
You also have to realize that most ground problems lies within ground frame work of the house that feed the PC. As we get further away from the node point where ground wire meet the Earth ground (usually outside the house), the potential with ground related problems rises. And I don't see how changing a PC can have any input to that problem.
I think I stop here before my post get too long :) |
| Good pic.. | jneutron
Nov 5, 2003 7:01 AM | | Thanks for the pic, tony..
A double shield by itself will not reduce the problem, as the flux trapped in the loop will hit all the same way..
In your picture, you forgot one thing..at the amp end, there is a 10K resistor from the signal to ground..
So, the shield/ground loop will distribute the voltage drop around the loop, based on the resistances of each component. But the voltage in the signal wire loop will show up only at the 10K resistor...ie. the amp input..
A balanced run will eliminate that entirely (within the cmmr capability).
The voltage distribution of the ground loop will depend on all of the wires and connections..if you use heftier everything, the loop voltage will be the same, it's just that the current will rise..if you beef up the ic ground, there will be less drop in that part, but it will not affect the signal loop at all.
My initial premise falls apart entirely if both components are only two wire. (well, almost entirely, as I've not included any capacitance issues..)
The ground loop we are talking about is just from the socket to the electronics..I'm not talking outside that small loop, to the entire house..
What I speak of here includes the pc's and ic's, so both should have some effect..whether it is large enough to do strange and audible things, I don't know..But, the beauty of it is if we understand how the mechanism should work, we can devise tests to look for it.. and confirm or deny it..it happens where I work, but that is low millivolt and microvolt applications with 30,000 amp supplies in the area..but, still, that annoying pop at home led me to think about audio issues..
It is interesting that anecdotal accounts say bryston amps don't care about power cords..Is their input section different somehow? Do they float the input shield, and apply it to a differential circuit, thereby bypassing the loop I am talking about??
Cheers, John |
| So what is the best way to reduce ground loops? | Tony_Montana
Nov 6, 2003 1:42 PM | | You said the voltage distribution of the ground loop will depend on all of the wires and connections. And that is true, especially about the connectors. Sometimes the connectors will collect dust between the contacts causing the resistance between contacts to rise. I have run cross that problem before, and buy unplugging the connector and cleaning them up do reduce loop resistance problems (it did mine).
But concentrating on power cord alone, what would be an ideal pc (as compared to stock pc) that would reduce ground loop [at least] from the socket to the electronics?
You also said;"My initial premise falls apart entirely if both components are only two wire."
Are you referring here to two prong pc connectors as oppose to three prong connectors? I have noticed that when alot of [audio/video] equipments are connected together and there is ground loop hum problem, the problem can be eliminated (or reduced) by lifting the ground on the equipments that have three prong connectors. But ofcourse that will raise safety related issues.
Thanks. |
| So what is the best way to reduce ground loops? | jneutron
Nov 6, 2003 7:28 PM | | Tony: ""But concentrating on power cord alone, what would be an ideal pc (as compared to stock pc) that would reduce ground loop [at least] from the socket to the electronics?""
I'm not sure yet..but if it's doing what I hypothesize, there may be something relating to relative pitch between two cords, or integral number of pitches. I'm not sure how resistance of the power cord and connections could really have a big influence, unless they swamp out a high resistance ic ground.
Tony: ""You also said;"My initial premise falls apart entirely if both components are only two wire."
Are you referring here to two prong pc connectors as oppose to three prong connectors? ""
Yes..my hypo as stated depends on the ground. If no ground, my hypo is no good.
I'm gonna build a test widget box to allow using a diff scope probe to look for it..If I do measure an effect, then I'll be able to see how it reacts, and be able to answer your question..If I see nothing, then I certainly can't answer your question using my hypo..
Cheers, John |
| You've been hanging around Jon Risch too long | skeptic
Nov 5, 2003 7:05 AM | | And you're starting to think like him too.
"My sub forms a ground loop with the outlet and receiver... each has a chassis ground connected to the wall outlet ground, and the IC completes the loop. disconnect the IC, the pop goes away..unplug the receiver, same thing."
Are you saying that if you disconnect the IC then you don't hear the pop in the main speakers? Are you saying that the pop isn't coming from rf noise generated by large inrush current elsewhere in the house and radiated directly into the unshielded preamp stages through the house wiring?
What about equipment where the signal is a floating ground and there is no connection between the chasis ground and the signal ground or dc power supply ground? What about where there isn't even a metal chasis or metal enclosure to ground at all? Are they immune to these pops?
Are you suggesting that this ground loop is created by the safety ground (green wire) or the grounded electrode (white wire neutral)? It couldn't possibly be the neutral because it would be dangerous and unacceptable to ground the signal to it. What about equipment that doesn't have a safety ground? Are you saying that there would be no pop? If ground equalizaton were a problem, the solution would be to create ground grid with a ground plane and a ground window the way telephone equipment at a CO is grounded, not to change out the wires. Given the short lengths and low resistances involved in signal grounding for a home stereo system, this seems unnecessary.
Are you suggesting that power cables can somehow surpress 60 hz hum or rf noise or pops. Certainly the rest of the distribution is not immune to it, especially if the house is wired with Romex which is unshielded. Shielding a power cable is a clear violation of its UL listing because it restricts heat dissipation and is not in conformity with the way it was rated for ampacity (unless you wire your equipment with mc or bx.) Besides, you are only shielding 3 feet of a leg which may be dozens of feet long, the remainder unshielded. Installing any kind of choke such as the ferrite beads some DIYers were using is extremely dangerous because it creates a high impedence ground which is in clear violation of NEC 250.
I am totally puzzled by your post and what you are trying to say. |
| I see you don't follow CA much...:-) | jneutron
Nov 5, 2003 7:21 AM | | SK: ""Are you saying that if you disconnect the IC then you don't hear the pop in the main speakers?""
No, the main speakers never popped..just the powered sub. and when the ic to receiver is unplugged, the pop from the sub disappears.
SK: ""Are you saying that the pop isn't coming from rf noise generated by large inrush current elsewhere in the house and radiated directly into the unshielded preamp stages through the house wiring?""
With the sub on, level unchanged, ic pulled from receiver, and either shorted or left open, the pop goes away. That removes the receiver entirely, leaving only the active sub which is still on.
SK: ""What about equipment where the signal is a floating ground and there is no connection between the chasis ground and the signal ground or dc power supply ground? What about where there isn't even a metal chasis or metal enclosure to ground at all? Are they immune to these pops?""
As I said to Tony, my premise cannot deal with ungrounded stuff, only when a ground loop is formed (capacitance may help ungrounded reception, but for now, that's beyond this discussion. But, I note..most of the pc discussion I've seen revolves around IEC cords..are IEC's required to have chassis ground to iec ground?. Safety ground should never be neutral..good point, and can never be stressed enough..
SK : ""Are you suggesting that power cables can somehow surpress 60 hz hum or rf noise or pops.""
No..I've no idea where you got that idea from..my hypo would suggest that how they are bundled may make the loop more susceptible because of physical loop size, but not any magical qualities..
All your safety related statements are excellent, Skeptic..I hope everybody reads them well and follows them..
I hope I cleared some things up..
Cheers, John |
| I see you don't follow CA much...:-) | skeptic
Nov 5, 2003 7:39 AM | | I don't follow CA at all. Several years ago, I posted there for a short time under another moniker but found the place totally disfunctional and a shill for advertisers. I left before I said something that would make them throw me out.
In your particular case of IEC cords with grounded chasis, perhaps ground planes and ground windows are the way to go. Equalizaton of ground potential thoughout a network is only a problem where the distances are large, or where as in this case the gain is very high and even the smallest of disturbances is objectionable. Perhaps a computer grade isolation transformer on your equipment would work too. How about a single AC source with a star distribution scheme for your HT receiver and subwoofer amp such as all power coming from the same power outlet strip? That would at least eliminate circulating ground loops within the house as a source since the reference ground of the receiver and sub amp would float at the same voltage above true ground all the time. |
| I see you don't follow CA much...:-) | jneutron
Nov 5, 2003 8:42 AM | | All good points..
My feeling? My home theater setup is just that...a simple, little, tiny speaker, 250 dollars with receiver/dvd 5.1 system.. Not something I'll go out of my way to address..And, I'm about to move..so it's not a high priority..
Cheers, John |
| Hold on there Skeptic! | RADAR O_Riley
Nov 5, 2003 9:13 PM | | John isn't incorrect (as far as I can tell) but he likes to make things complex to impress people. That's what makes his StarTrek science look so much like Jon's nonsense. They're both so busy playing the silly game "impress others with my knowledge" that they have to work to provide simple explanations, even when they know their topic perfectly.
But when it comes to knowledge and honesty, there is NO comparison between Jon and John. Night and day, Skeptic, night and day. ;-)
Let me add a word of thanks for proving the point I tried to make in my earlier post. Even you couldn't figure out what the heck John was saying, even tough he could have been clear and direct if he'd wanted to do so. It no longer impresses me at all. Quite the contrary; It's gotten rather old and tiresome.
R.O. |
| Hi tony | mtrycrafts
Nov 5, 2003 11:10 PM | | You have a link to your picture posts you post at AA DIY about cable fields, etc, I read about recently? |
| Here we go again. | skeptic
Nov 6, 2003 8:12 AM | | I just don't understand why this isn't a dead issue already.
Here are facts;
Your amplifier, receiver, cd player or whatever appliance is connected to a vast electrical network comprising countless thousands of miles of feeders, transformers, switchyards, overhead power lines, generators, overhead neighborhood power lines, circuit breaker panels, hundreds of feet of underground feeders and house wiring, not to mention millions of devices all plugged into the network, consuming power and switching on and off all the time. The power cord between your wall outlet and your appliance is the smallest least significant part of it. If it can carry the required current without much voltage drop that is all it can do and no more. It cannot filter RF noise. It cannot compensate for voltage anomolies of any type already in the system. It cannot make up for any of the shortcomings of the rest of the network. It cannot improve the performance of your sound system one iota. Neither can the outlet.
However, if you are so brainwashed or pigheaded as to believe it can, here is a low cost alternative to buying expensive power cords that will easily better any of them.
Have a technician replace the power cord with the same type of wiring that you have in your house, Romex or BX. Have a licensed electrician remove the receptacle and hard wire to the to the network through a shutoff switch (it can be a 100 amp safety switch if you desire.) You now have the same performance from your "power cord" as you have for the rest of your house. If you can find another point to hard wire from that is closer to the circuit breaker panel than your present outlet and you reduce the overall length of the run by more than the few feet of power cord you would use to the receptacle, you have actually beaten the performance improvement you would get with a "perfect" power cord.
No, don't thank me, just send money for this consulting advice. |
| In the communication world..... | Tony_Montana
Nov 6, 2003 2:00 PM | | ...performance of equipments (especially S/N ratio) can be enhanced by connecting its ground post to true earth ground (usually 6 feet rod in the ground). That might benefit amplifier performance also since most amp have a ground post in the back. That might be the only improvement one can make as far as power enhancements are concerned. |
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