[rds]

Ground is a common return path or voltage reference. What is so hard to understand about that?
Electromagnetic waves really can be 'sent' and 'returned'.

"A signal propagates down a cable as a transverse electromagnetic wave between two conductors"

People who deal with electronics generally know this, but refer to it in that way and they'll probably just look at you funny, sort of like if you go to a car dealership and ask to see their 4 wheeled self-propelled motor vehicles.

In your statement you actually concede that a signal is 'sent' in that it leaves at some point in time and arrives somewhere else at a later point in time. The semantics of your argument are sort of like when you leave somewhere in the world travel around and get back to where you started at what point are you returning and not leaving? Most people would say just after the half way point. Same logic applies to signal cables.

 

[Steve Eddy]

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Originally Posted by rds /img/forum/go_quote.gif Ground is a common return path or voltage reference. What is so hard to understand about that?

I wasn't speaking of difficulty to understand, I was speaking of too little understanding which can lead to misunderstanding such as the case here, as well as others for example the notion that "ground" is some magic, one-way portal that noise drains into, or notions as to what constitutes the "signal path."

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Electromagnetic waves really can be 'sent' and 'returned'.

Care to give an example of that which doesn't involve reflection or energy storage?

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In your statement you actually concede that a signal is 'sent' in that it leaves at some point in time and arrives somewhere else at a later point in time.

Yes. It leaves at one end of the cable and arrives at the other end of the cable at a later point in time.

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The semantics of your argument are sort of like when you leave somewhere in the world travel around and get back to where you started at what point are you returning and not leaving? Most people would say just after the half way point. Same logic applies to signal cables.

Except where signal on a cable is concerned, you don't end up where you started. You start out at one end of the cable, and arrive at the other end of the cable, hopefully never to return.

k

 

[fishski13]

come you two, enough already...we get the point, pedantic semantics aside.

think electron flow and current, and all is proper and good.

 

[Steve Eddy]

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Originally Posted by fishski13 /img/forum/go_quote.gif think electron flow and current, and all is proper and good.

Sure, as long as your signal source is cylindrical, has an electrode at each and and says "Eveready" on it.

But ok, I'll shut up.

k

 

[qusp]

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Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif Personally, one is free to do whatever they want for whatever reasons they want. But when it comes to understanding what's actually going on, that's another matter entirely. And from a cable's point of view, there's absolutely no distinction whatsoever between being driven from an unbalanced source or a balanced source. k

why is that?? I cable doesnt have a point of view at all if you wanna argue semantics

and sure the signal does travel up the signal AND return or rather it exists between the potential for these signal poesl (not actually between the conductors), but for there to be a signal, there needs to be a ground potential to begin with, in single ended circuits the ground isnt active like in balanced, meaning the resulting signal itself (however you want to describe or visualize that) doesnt have the same strength/efficiency as if ground were actively opposed to signal, so I try and help it out some, whether thats just being superstitious or whatever, thats the way I handle SE cables. please explain then if there is no distinction, then why is it most single ended connectors are built with a larger/thicker terminal for ground (RCA, mini, 1/4", BNC, sennhieser), while XLR, USB (just a couple) have all terminals the same size?? its obvious why balanced requires the same size for the opposing poles ie the common mode; but why are SE designed like that then?? and why many circuit designs call for a thick wire to join ground planes in multiboard layouts?? why not just the same gauge as the signal traces or power wires?? is it coincidence?? coaxial connectors I can kinda understand with regard to shielding. but I dont think that is the whole reason and it doesnt cover the rest

 

[dbfreak]

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Originally Posted by stew1234 /img/forum/go_quote.gif I'm wondering if it will make any difference sonically if I use some nice copper wire I have for L/R channels and some lesser wire for ground on a single ended headphone output? I'm also wondering about RCA outs. I could see how the ground channel on a headphone out might have an impact but it seems to me it doesn't matter on an RCA out long as it grounds the signal.

I see it as purchasing the latest Milwaukee 18V Lion 1/2 Hammer Drill and using Black and Decker drill bits to get the job done.

 

[Steve Eddy]

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Originally Posted by qusp /img/forum/go_quote.gif why is that?? I cable doesnt have a point of view at all if you wanna argue semantics and sure the signal does travel up the signal AND return or rather it exists between the potential for these signal poesl (not actually between the conductors)...

No, the signal does indeed exist between the conductors, in the form of an electromagnetic field.

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...but for there to be a signal, there needs to be a ground potential to begin with, in single ended circuits the ground isnt active like in balanced, meaning the resulting signal itself (however you want to describe or visualize that) doesnt have the same strength/efficiency as if ground were actively opposed to signal...

That's incorrect.

1 volt across an unbalanced output is no different than 1 volt across a balanced output. They have exactly the same strength and efficiency. There is absolutely no difference whatsoever.

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...so I try and help it out some, whether thats just being superstitious or whatever, thats the way I handle SE cables.

There is nothing to help out as there is nothing that needs any help.

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...please explain then if there is no distinction, then why is it most single ended connectors are built with a larger/thicker terminal for ground (RCA, mini, 1/4", BNC, sennhieser), while XLR, USB (just a couple) have all terminals the same size??

It's simply a matter of design.

RCAs and BNCs were designed for coaxial type cables where you have a center conductor surrounded by a second conductor which also serves as a shield. RCA and BNC plugs preserve this coaxial nature.

1/4" and mini are also referred to as "phone plugs." That's because that style of plug was invented over 130 years ago for use in telephone switchboards. That the ground sleeve is longer than the others has to do with its mechanical design, not its electrical behavior.

As for the Sennheiser plugs, the pins are differently sized for polarization purposes.

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and why many circuit designs call for a thick wire to join ground planes in multiboard layouts?? why not just the same gauge as the signal traces or power wires?? is it coincidence??

Depending on the layout of the circuit, you could use the same gauge as the signal or power wires.

In a circuit, "ground" is a single node that may be shared by different portions of the circuit. However they may not all terminate at the same physical point (i.e. star ground). Which means that one portion of the circuit may be tied to a trace which might have other currents flowing through it.

And because of Ohm's Law for voltage (E = I x R), the resistance of that trace determines how much voltage will be dropped across it for a given amount of current flowing through it. The lower the resistance (as can be achieved with a wider trace or thicker wire), the lower the voltage drop across it and the less noise that can be picked up by the circuit.

k

 

[qusp]

lol, you just want to argue, then why are balanced signals always referred to as having more swing?? a signal that has an actively driven opposing signal of the same strength is not stronger than one that simply has a neutral ground referenced wire?? its certainly louder, to the point that when switching from balanced signal to SE on my sound card (to my active monitors) given the same source material the signal strength is louder. if I take one conductor of a balanced signal; lets say the positive one; and combine that with a ground wire for a single ended signal, the resulting signal is only half the strength.

oh hang on, I see what your on about, you are saying its the signal that is stronger, not the cable.... jeez you are being picky if thats the case

sure there is a field in between, but its still more of a potential field as well, if you put your hand in between 2 signal/power carrying wires (properly insulated) you do not get zapped... do you?? but the signal still exists. that was my point on the potential. the field still passes through your hand though, granted. and what about the situation where you have a device powered or a signal supplied with 2 wires arriving at the device from opposite sides; so at no point is there an 'in between'. still works then; perhaps a little noisy, but still functional

I remembered the phone plug (safety) explanation afterwards; i'll concede that for sure and I already conceded that BNC and RCA could very well be so the signal was surrounded by ground as a means of shielding.

i've noticed a theme in your posts where you go around arguing with people; why is that??

 

[Juaquin]

Remember what they say about arguing on the internet...


The bottom line is that Koyaan wants everyone to think of signals in a different way than most of us learned and convention would dictate. That's fine, but most of us are just going to keep doing it the way we're comfortable with. If he'd like to start a crusade, he's welcome to do that. Don't bother arguing with him about it because it's clear that he's quite strong in his belief (or he just likes arguing), and that's fine.

 

[Mannevond]

How about dropping the semantics and get down to designing something that works

 

[murrays]

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Originally Posted by qusp /img/forum/go_quote.gif lol, you just want to argue, then why are balanced signals always referred to as having more swing??

Not always. Only when driven by a topology where the 2 output nodes are driven at equal magnitude and opposite polarities. That causes the voltage to be double that of a topology where one node is driven and the other is passive (single-ended).

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Originally Posted by qusp /img/forum/go_quote.gif a signal that has an actively driven opposing signal of the same strength is not stronger than one that simply has a neutral ground referenced wire?? its certainly louder, to the point that when switching from balanced signal to SE on my sound card (to my active monitors) given the same source material the signal strength is louder. if I take one conductor of a balanced signal; lets say the positive one; and combine that with a ground wire for a single ended signal, the resulting signal is only half the strength.

That is true because the voltage is doubled in the "balanced" case as compared to the "singled-ended case". This is a consequence of the circuit topology, not the actual wires being used.

Remember that true balanced signals (as used in professional audio) are used specifically to avoid the need for a signal ground. One main purpose is to avoid ground loops.

Other posters have hit the correct point: that you must consider the entire circuit, including the return. Unfortunately, the way most circuits are schematically drawn tend to hide this reality. The ground/return is mostly implicit for convenience of drawing clarity. Electrons must start at the power supply and end up back there again.

So, to the OP, yes: use the same quality wire for all signal-carrying conductors within a cable.

 

[Steve Eddy]

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Originally Posted by qusp /img/forum/go_quote.gif lol, you just want to argue...

No, I don't. I just want people to understand rather than misunderstand and come to a whole lot of erroneous conclusions because of it.

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...then why are balanced signals always referred to as having more swing??

They're only always referred to as that by those who don't know what they're talking about. They confuse the concepts of "balanced" and "bridging" and often end up conflating the two.

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a signal that has an actively driven opposing signal of the same strength is not stronger than one that simply has a neutral ground referenced wire??

1 volt is 1 volt, whether it's coming out of a balanced output or an unbalanced output.

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its certainly louder, to the point that when switching from balanced signal to SE on my sound card (to my active monitors) given the same source material the signal strength is louder.

That has nothing to do with whether or not the output of your sound card is balanced. It's simply a consequence of the particular method by which they achieve a balanced output, which in this case is by bridging together two single ended outputs.


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oh hang on, I see what your on about, you are saying its the signal that is stronger, not the cable.... jeez you are being picky if thats the case

What I've been on about has absolutely nothing to do with whether anything is stronger. What I have been on about is that the cable doesn't know balanced from single ended.

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sure there is a field in between, but its still more of a potential field as well, if you put your hand in between 2 signal/power carrying wires (properly insulated) you do not get zapped... do you??

No, you don't.

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but the signal still exists. that was my point on the potential. the field still passes through your hand though, granted

Yes, the signal still exists because the signal is the electromagnetic field which exists between the conductors.

Consider:

The signal propagates down the cable at somewhere near the speed of light. But that's not because the electrons in the conductors are shooting down the cable at that speed. The drift of the electrons is literally slower than you normally walk.

The reason the signal propagates at such a speed is because the signal is the electromagnetic field that exists between the conductors.

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i've noticed a theme in your posts where you go around arguing with people; why is that??

Simply because if I see something that's incorrect, or happens to be a pet peeve of mine, I'm not shy about speaking my mind on the matter.

k

 

[digger945]

^Do you subscribe to electron flow or conventional flow?

 

[qusp]

I edited my post; please explain why then that if there is a signal that originates from a point a ground and signal wire but they get split up and then 'arrive' at the 'destination' from opposite directions; is there still a signal 'between the conductors'?? the device will still work this way (a little noisy perhaps), but where is this signal you speak of??

 

[qusp]

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Originally Posted by murrays /img/forum/go_quote.gif Not always. Only when driven by a topology where the 2 output nodes are driven at equal magnitude and opposite polarities. That causes the voltage to be double that of a topology where one node is driven and the other is passive (single-ended). That is true because the voltage is doubled in the "balanced" case as compared to the "singled-ended case". This is a consequence of the circuit topology, not the actual wires being used.

agreed, while you were replying, I was adding something to that effect to my post

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Remember that true balanced signals (as used in professional audio) are used specifically to avoid the need for a signal ground. One main purpose is to avoid ground loops.

among others yes

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Other posters have hit the correct point: that you must consider the entire circuit, including the return. Unfortunately, the way most circuits are schematically drawn tend to hide this reality. The ground/return is mostly implicit for convenience of drawing clarity. Electrons must start at the power supply and end up back there again.

yes, which tends to go with signal flow

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So, to the OP, yes: use the same quality wire for all signal-carrying conductors within a cable.

agreed, the same or better depending on the number of signals needing to be grounded or the paranoia of the constructor