serengetiplains said:
Error in logical thinking, sorry. The different signatures ARE possible. Whether these are AUDIBLE remains to be seen. Not many (probably no) people say that it is impossible that it is audible. They just say: "show me!". So far, no evidence. Don't put words in the critic's mouth that they didn't say.
You conclude from the fact that it is POSSIBLE, that it is true. Wrong thinking.
Jan Didden
Hi Jan,
Right. I think it depends heavily on the situation at hand. Extremes are always bad.
If you have a high impedance system, the cable may be more important and audible. Likewise a long cable run. Enviroment can play a big role here as well.
-Chris
Right. I think it depends heavily on the situation at hand. Extremes are always bad.
If you have a high impedance system, the cable may be more important and audible. Likewise a long cable run. Enviroment can play a big role here as well.
-Chris
As I suspected, you have made the assumption that if there is a ground loop, you will hear it via line frequency noise..hermanv said:
A ground loop is a physical construct. It is NOT the noise, it is the construct.
Go back and look at the list of 4 items which result from ground loops. Second thought, I'll paste them..
1. Steady state hum.
2. Music power modulated hum.
3. External noise pickup, like sub pops.
4. Alteration of audio phase by induced voltages at input.
While I will concede that 2 and 3 are probably in reverse order, nontheless, all 4 items are a consequence of a ground loop. The fact that you may be unaware of number 4 and 2 does not mean they do not exist, and are of no importance.
In tracking down work related issues, all of these have bit me in the tail..of course, for me at work, it was not music that was the signal of interest, but rather, a computer controlled BALANCED power supply control signal (actually, many different computers and supplies.)
As it turns out, while my work related loops are humongous in comparison to anything home or even in a stadium, the issues are exactly the same.
And, in the course of my own hobby, I've even had oscillation as a result of chassis and shield related audio currents as a result of loops..Star grounds have their issues.
I am quite familiar with that large body of knowledge on ground loops within the engineering community. Unfortunately, it falls quite short of my requirements, although it is certainly an excellent start. I am hoping that what is required in my work arena for success (and we are quite successful) can be a valuable contribution to the knowledge that you guys here already have. (measuring a microvolt in a 30 kiloamp, liquid helium, 10 tesla environment is a daunting task..big toys, so to speak...)
hermanv said:
Again, it is not just hum.
I have never said there is. Hopefully, I won't accidentally state something that could be construed that way..if it seemed that way, I apologize..hermanv said:
hermanv said:
It is distinctly possible you did not see anything because you were not looking in the right place.
It is trivially easy to totally blast away "dielectric involvement", skin effect, burn in, grain boundary, 5 nines, solder alloy, plating, all the usual "garbage explanations" using entirely proven scientific understandings..but that, I believe, is rather counterproductive. This is exactly what you are doing, saying the ground loop is not it...I find it rather funny that a cable "believer" is trying to use scientific knowledge to diss a "nasty naysayer" like me (historical label...don't ask..😀 )
As I told Jan, some of the stuff I'm talking about seems rather counter-intuitive... For example, in the case of my 100 foot unbalanced rig, how did I get rid of the hum and noise?? Simple, I tie wrapped the unbalanced line feed and mike input cable to the 100 foot long extension cord every foot. No twist, no gap... against it..and, covered the thing with that mesh stuff to make sure it was snugly against it..Oh, and one very important item....I had to make sure the pitch of the line cord was not an integral of the pitch of the mike cord, that would have enhanced coupling, as the differential pair within a mike cord will heavily couple if the twist pitches are matched.
The first inch or so between the AC cords and the the shields is the most important..moving the ground farther from the AC cord INCREASES the loop integral, not decreases. Once your a foot away, moving it doesn't change it at all, and you are at the mercy of the denominator in the transfer function I posted.. You are not looking in the right place..
hermanv said:
It is relevant because nobody has ever produced consistent tests which would explain what you are trying to get us to believe. That is because an IN situ evaluation is what you should be doing.
hermanv said:
I will never deny you your opinion..sorry if I came across that way.
I will change your opinion, based on theory and measurements, and along the way there will be informative, well meaning dialogue, all will benefit, me included..
hermanv said:
Have you pushed 100 mA AC 20 to 20Khz between the input shield and the line cord ground, input shorted, looking for output? Or, performed the test I drew?
That would be a good starting reference, no?
From what you describe as a ground loop, I believe you are not looking in the right place.hermanv said:
How many man years have been devoted to this very issue? And, where are we? Do you think perhaps you need to re-group and consider the problem from a different perspective? That is what I am doing.
I propose that which I have not seen addressed, nor understood. That is because I work in a very different field..
Cheers, John
That is my ultimate goal.ending the bickering. Course, advancing the knowledge base is also good..hermanv said:
I do not see the utility of that path, as I recall several people used AP units to do this, and produced ZERO results. In fact, John Curl started that with some tests he did using some older equipment, to no avail..hermanv said:
So that path is useless.
However, given the state of engineering when it comes to low impedance, high power systems out there...THAT is fertile ground for improvement..boy are there a lotta mistakes being made in that regard..
hermanv said:
We agree.
Cheers, John
John,
I don't follow you in all details, especially not the relationship between ground loops and delays, however, it seems the ground loops are the source of problems in your theory. One thing I am not sure if I get right then is if protective earth in the mains connection is necessary for ground loops? It seems so to me, but maybe I am missing something. Or to put it another way, in the case where units do not have protective earth, and where chassis may be connected to signal ground but are galvanically isolated from any mains leads, could there still be harmful ground loops of the type you are referring to? I certainly see we can have ground loop via the separate channel cables for the signal, but that seems not to be what yuou consider.
I don't follow you in all details, especially not the relationship between ground loops and delays, however, it seems the ground loops are the source of problems in your theory. One thing I am not sure if I get right then is if protective earth in the mains connection is necessary for ground loops? It seems so to me, but maybe I am missing something. Or to put it another way, in the case where units do not have protective earth, and where chassis may be connected to signal ground but are galvanically isolated from any mains leads, could there still be harmful ground loops of the type you are referring to? I certainly see we can have ground loop via the separate channel cables for the signal, but that seems not to be what yuou consider.
Christer said:
Detrimental feedback in the audio regime can cause the delays for imaging localization clues, as well as amplitude ones.
I struggled at first understanding why the hearing researchers were working down at the ten microsecond regime, as I couldn't figure how our hearing could relate to the implied bandwidth. But, after modelling it myself, saw how sensitive we had to be to localize sounds. What really was interesting wasn't just the absolute positioning, but the incremental positioning cues and timing. Sorry to talk about that on this thread, but the important part is the level of delay we can hear when it's relative..
I'm wrestling with HOW to measure that kind of delay with a real power amp pushing a load, as I'd prefer 1 uSec and below resolution to get any accuracy, and dummy power loads just don't pull that kinda slew rate out of an amp very well. Nor is measuring the voltage across them easy to do accurately.
Transformers will couple..remember, I'm not talking about hum, but stuff much higher in the frequency range. Where parasitics to the grounds can raise issues. Power line filters, snubbers, and the like..
Separate input channels is also interesting, but it's simple enough to just put them next to each other, that'll reduce shield to shield loop pickup. If they are just loose, any loop is suspect..
I remember seeing a two inch by 1 inch copper braid being used as interchassis ground, and was amazed by the fact that it wasn't working. to get rid of induced coupling..
As for audio stuff with no third prong...So far, everything I've seen with no ground had a zip cord style power cord. That construction is almost the worst method of getting the AC current from here to there, as it produces a very mean dipole field. Only spreading the hot/neutral apart is worse than just zip..
Of course, what's in the wall...romex?
Anybody in their right mind ever twist the romex to neutralize the dipole? Or, like I did in the past, lay it flat and staple it...
Cheers, John
janneman said:
You appear to have followed with a strawman of your own Jan. I don't recall anyone saying all objectivists hold cable audibility is impossible. 'Impossibility' isn't really relevant to the discussion at hand, the existance of differences has been the core of the discussion and objectivists do indeed consistently claim there are none in a properly functioning system. So while what you say is perhaps literally true, the difference between 'impossible' and 'never happens' is logical hair splitting and not really germain to the discussion.
As these discussions continue, several people have posted links to other sites and individuals searching for an explanation to the cables sound different debate. There a re a fairly large number of web sites devoted to the topic. Some of these links lead to people who have obviously spent some real time addressing the problem and asking quetions.
Many of the links that show the most understanding and scientific approach end up with further links to a site that sells cables based on the originators "discoveries". So it seems that people who make progress in understanding the whole cable sound issue can not resist the temptation to make cables that sell for hundreds but presumably cost far less to make.
This happens often enough that it is easy to believe that there are some basic underlying physical propeties or principles that are readliy reproducable and consistent. The people who have learned what works are either reticent because they only have their own ears as proof or they now feel thay have a valuable business secret to protect.
One of these sites http://www.positive-feedback.com/Issue7/empiricalint.htm
was posted earlier (but now I can't find it to credit the poster). Here is someone who has thought it through and obviously performed some experiments. Little hard data but careful reading will reveal some information also hinted at on many other sites.
Many of the links that show the most understanding and scientific approach end up with further links to a site that sells cables based on the originators "discoveries". So it seems that people who make progress in understanding the whole cable sound issue can not resist the temptation to make cables that sell for hundreds but presumably cost far less to make.
This happens often enough that it is easy to believe that there are some basic underlying physical propeties or principles that are readliy reproducable and consistent. The people who have learned what works are either reticent because they only have their own ears as proof or they now feel thay have a valuable business secret to protect.
One of these sites http://www.positive-feedback.com/Issue7/empiricalint.htm
was posted earlier (but now I can't find it to credit the poster). Here is someone who has thought it through and obviously performed some experiments. Little hard data but careful reading will reveal some information also hinted at on many other sites.
I believe the argument is over "audibility", when we use well understood physics and math to model effects claimed to be audible and the #"s are orders of magnitude below the noise floor (insulator da, Cu, Ag metallurgy) I don't even feel the logical necessity to pull out the dbt established audibility thresholds (take your pick of room noise, recording noise, even thermal noise in some instances)
but we are expected to give full credit to subjective reports where no effort has been made to match trials to dbt established thresholds - dbt doesn’t prove no one can't hear differences below the statistically significant levels, but it does establish where we do expect differences to be heard - but we are assured that the subjective impressions are robust, specific to what the "experiment" is testing and can easily be heard through the known to be audible faults in the test setup
but we are expected to give full credit to subjective reports where no effort has been made to match trials to dbt established thresholds - dbt doesn’t prove no one can't hear differences below the statistically significant levels, but it does establish where we do expect differences to be heard - but we are assured that the subjective impressions are robust, specific to what the "experiment" is testing and can easily be heard through the known to be audible faults in the test setup
It is suprising to find that so few blind test are made.jcx said:
If I search net for it, the number of results from such tests are close to zero.
I think reason is this:
Those who do not believe you can not hear an interconnect
find such a test meaningless. Like hunting for what cant be found.
Those who do believe you can hear are a bit afraid test result would tell you cant here a thing. Results showing nothing different than you get from randomly guessing.
So here we are. Left without any really verified knowledge in this matter.
Some with one opinion and some with another opinion.
Whatever technical speculations, using whatever logic, anyone makes will not prove a thing.
🙂
This is a hobby and this forum is largely devoted to advancing that hobby. Here many of us share stories about what we did to make our systems sound better. There are posts about certain brands, there are posts about room treatment, there are posts about modifying the electronics or even building your own and there posts about cables.jcx said:
Sharing this kind of information leads to better sound for most participants. After all, one can easily buy a complete pre-packaged system at the local mass marketer. If you believe that there is nothing further to be gained why are you here?
I am quite happy with the improvements made to the sound of my own system with exotic cables. I am not that happy with the price, like many I suspect that it can be done for less money. I have little to gain by the endless flame wars over cables except to help others to get sound as good as or better than what I hear at home or to satisfy myself by understanding what is going on, perhaps leading to better sound yet.
Most people agree that the exotic name brand equipment; the Krells, Levinsons, Lamm and a long list of others sound better than the mass market stuff. Most of these exotic brands use exotic components, especially capacitors with carefully chosen dielectrics. How can one easily accept that the expensive parts sound better in an expensive product but get all twisted up when the same careful control over material and content is applied to make the cables?
There seems to be an assumption that special materials can only be an improvement if they are enclosed inside the electronics housing but as soon as the same attention to second order effects or materials purity is applied to devices that are used to interconnect two electronic housings suddenly even the possibility of improvements become absolutely un-acceptable.
I think that many do not understand the complexities of what happens inside an electronics enclosure but feel completely confident that there can't be anything about cables they don't understand.
Do people insist on DBT tests on Mark Levinson's amplifiers made with two different sources of internal capacitors? No, people are happy to believe that Levinson might know what they're doing. We don't insist on DBT tests to prove one brand of electronics could sound better than another. (Not quite) There are some who have claimed that "all amplifiers sound the same". Just take your good 'Ol Pioneer reciever over to an audiophile's house, someone who owns Conrad Johson, Mark Levinson, Bryston, Lamm etc, etc. It shouldn't take any time at all to bury that myth.
rdf said:
... or they claim, sometimes implicitly, that any audible differences, if they exist, should be heard in DBT or can't be heard above a given noise floor etc. Those claims ride on large assumptions, which I do not now care to explore.
Jan, you might want to reread my post. Like rdf, I beg to differ on your view of what I wrote.
BTW, Hermanv, I was the person who posted the reference to the PF interview of Steve Nugent. Steve looks to have considerable experience with cable (I mean, holy geez) and, yes, he makes his own cables (GASP! ... why would a person experienced in cables make cables??). Steve's perspective, if I've properly pieced it together, is that audible differences between cables arise, as to first order differences, from RLC and, as to second order differences, from DA, winding geometry and metallurgy. Looks reasonable to me.
Reasonable indeed,
Until the $1500 power cords come to mind. And presuming these power cords, if they "do" anything at all, will "UNDO" the effects of hundreds of meters upstream of common Romex?
Until the $1500 power cords come to mind. And presuming these power cords, if they "do" anything at all, will "UNDO" the effects of hundreds of meters upstream of common Romex?
poobah said:
Free cables for all! Wait, free everything for all!
Who said anything about undoing? Not further doing better fits the discussion, especially not further doing just before EMI sensitive equipment.
hermanv said:
Hi Hermanv
People? We? Don't insist on DBT? Are you new to this forum?
Most of the contributors to this thread honestly believe there is no audible difference between reasonably specced amps. All you hear, to put it politely, is a combination of snake oils and delusion.
If amps, cd players and passive devices cannot possibly sound different, where does that leave wire? I am surprised noone has mentioned the great Randi so far.
It may be more productive to discuss cables with your butcher.
Were it not for wanting to sleep at night I would sell MuMetal wall shields.... hmmm... decorator colors... acoustically absorbing... $8000... yeah... yeah... that's the ticket.
analog_sa said:
I am not one of them. I remain, shall we say, mildly unconvinced?
Keep in mind, I've never heard a difference. But then again, I've no proof either way.
I do know that once specifications are met, they should sound the same. I do not know if all the required specifications relevent to human hearing have been established.
I grin at the thought of the dilbert strip with the garbageman who corrects dilbert's equations..he's my role model..not dilbert..analog_sa said:
Cheers, John
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