Audio over Cat5/5e/6 cables - Page 3

Your first statement shows you don't understand the nature of noise induced by external fields onto a conductor, how impedances, and wire geometry play a part in how this noise energy manifests itself.

I will try to help: balanced vs unbalanced - deals with impedances. differential vs single ended - deals with the nature of the signals themselves, specifically their voltages. Wire geometry - deals with EM theory of the systems interaction with itself and surrounding environment. To say that any of these things are necessarily related would be technically incorrect per the definitions of each of them regardless of existing industry trends.

No, it show that he knows why the wires are twisted together in a balanced interconnect. You, clearly, still don't get this.



You're simply incorrect in your understanding of the oldest method of transmitting audio signals.

I said a balun was a transformer, and it is.

A balun typically used to connect a dipole antenna to a 75R transmission line, will not work as an audio transformer in any useful way. This use, plus later HF variations used for data and networking are pretty much the same.

For it to work at AF, it will typically need a larger core CSA and considerably more primary inductance.

My point was that if you go into ratshack and ask for a balun, you'll get something like this.


Different brand, opened to show the insides.
http://www.user.dccnet.com/jonleblan...ips-balun3.jpg

Which will not be useful at all at AF, where you need a proper AF transformer whether or not you want to call it a balun or not. I've been doing PA for a long time and no one has ever referred to a matching transformer this way to me, whereas it's usage in RF is commonplace.

That is just one particular kind of Balun. And yes that is a Balun. But there are many MANY other types of baluns and transformers used for audio and video. Just because some schmoe at Radio Shack doesn't know what they are doesn't mean they don't exist.

Just google "audio balun" or "video balun" and you'll have hundreds of choices from endless vendors and manufacturers.

The links support my assertions. I have asked you this before with endless silence being the result but will try again anyways: Do you have anything at all more credible than something you pulled out of your a**?

Yes, as did I and many others.
You implied that a BaLun is only used for RF signals, you were corrected.


...but still don't understand.


...or thinks they can only be used at RF.

It is not ridiculous at all, and your point about bandwidths and correct usage actually proves the point I was trying to make: use the correct device for the job. An RF balun will only be useful for audio transmission over Cat cables if it is in the digital domain or on a carrier. Use a quality Jensen et al transformer designed for line level AF band transmission.

I was an RF engineer for many years and did live sound also. I only ever heard 'balun' used in RF.

Perhaps this a common US usage.

I don't bother trying to explain anything to you, because you don't have the ability to understand anything, as you've clearly demonstrated in this thread.

And there are many people here who also wouldn't know the difference and would walk out with what I showed a pic of and wonder why it doesn't work at AF.

well now you know better. as mentioned many times, a BaLun converts balanced to ubalanced, weather it's RF, audio video or power.


...and you never thought to ask someone what this acronym meant?


Apparently, you're one of them.

You aren't helping anything except making a confusing mess out of not an enormously difficult subject. Balanced vs unbalanced doesn't have anything to do with the impedance of the cabling, but the impedance of the conductors relative to ground. As I pointed out before, and which you seem to have backtracked on, is that a balanced line is not necessarily a differential line, but can be. This is probably a step too complicated for you, and it isn't hugely relevant for the noise rejection discussion. Whether the signals are symmetrically opposed or not doesn't have any impact at all on the noise rejection of a balanced line because the noise will be equal and opposite, and if the conductor impedance to ground is equal and the noise is induced equally and the conductor length are equal, the noise will cancel out, regardless of what the signal on the line is doing which is irrelevant.

There are particularly good wire geometries to use in a balanced line which achieves as close to equal noise induction on both conductors as possible, and that is paired conductors that are as close together as possible, and twisted together to hold them close together and help maintain equal noise induction into both conductors. The twist also helps maintain the cabling impedance stability which isn't really relevant for the noise induction but is relevant for the signal. A particularly horrible cable to use for a balanced line would be coaxial cable because the impedances to ground of the two conductors are totally different, as are their geometry, and because one of the conductors is designed as a shield, it will make noise rejection not work nearly at all because the noise will no longer be common to both conductors. Coax is designed and excellent for unbalanced transmission, twisted pair is designed and excellent for balanced transmission. There are also many shielded paired cables that are also excellent for unbalanced transmission, but you'll also notice that they often aren't tightly twisted if at all, because the twist isn't relevant unless you are using a balanced line.



Again, I'm not clear what you're saying here.

It's really quite simple: balanced line you use twisted pair. Twisted pair doesn't do anything for you unless its a balanced line.

Unbalanced line: you are relying on shielding, so use heavily shielded cable, either a shielded paired cable or a coax type cable.

Grow a brain, of course I knew what it meant, but you obviously like to be a smartarse and selectively quote. I have now made more than one post where I said I think the misunderstanding is because of different usage in different parts of the world.

Now there is a strong argument. lol!

OK, assuming for a moment that were true...

What is your excuse for pretending to show up here trying to be useful to the OP's plight but not explaining these potential points of confusion?

I have little doubt I know the answer to that. lol!

Wow, you're a tough one!

you posted the same thing over and over, demonstrating that you don't have much of a clue.

Okay, well just because you've never heard of something doesn't mean it doesn't exist or isn't commonly used. As already pointed out obviously an RF balun is totally inappropriate to use.

Here's just a handful of AV baluns for various uses:

http://www.etslan.com/AudioVideo.htm
http://www.intelix.com/products/balun_audio.htm
http://www.muxlab.com/products/ve_avd_s-av_balun.html


And there are countless more.

You are wrongly limiting the term Balun to mean only one specific and particular type of balun you are familiar with, but there are many many other kinds out there.

Not all baluns are created equally. All types available. Get the right balun based on your wiring to retrofit.

IMHO, just use the designated cabling/wiring for the application.

Bollocks, go back and re-read, rather that just selectively quoting. You just want to be a smartarse because of a terminology difference. I have explained why, but simply taking cheap shots seems to be about all you want to do. The term came from RF, and that is it's most common usage here in my experience.

no need to assume.


You're obviously angry that you've been schooled.
When you were corrected two pages ago, you retorted with a lot of garbage, proving that you don't know what you're talking about. You've been corrected a number of times since, yet still come back to this nonesense.

Again, no it didn't.

Below the equator, they work in reverse. They are called UNBAL's. LOL!!!

In the same way that you are incorrect to assume that a term in common usage where you are is universal everywhere else.

Look Chris, I'm tired of responding to your statements in which you try to put words in my mouth, which posted evidence would support, I never said. You clearly have some gaping holes when it comes to knowing the theory behind this stuff.

For example does this statement you made


somehow contradict mine which you felt the need to spend a paragraph addressing:


Then you said this:


Either you never read my response to your post or you like dwelling on the past but I conceded your point on this many many posts ago. Give it up already.

You really seem to be struggling hard to point me out as being the devil and yet have not supporting evidence contradicting anything about my last post other than the school of Duvetynes hand waving.


This is precisely what I'm reffering to when I suggest you don't get it. You should look at the link about UTP on wiki. Twisted pair does help in unbalanced circuits because it reduces differential noise. Maybe you should ask yourself if you've ever heard of a perfect ground before? They all have impedance which can and will be modulated by noise. Differential noise is a problem for unbalanced circuits too.

Bottom line is I have better things to do than go round and round about this stuff repeating myself. You clearly have some learning to do and don't appear to be willing to even listen to reason. The links are there, now you need to understand whats in them.

Typical and worthless as ever.

And I've kept asking you to point out what exactly you disagree with, and you can't do that, you just keep saying I don't know what I'm talking about and I can't really discern what it is you have a problem with.


That's because your statements are confusing, unclear, and I don't really know what it is your disagreement is even about.


I did, but you are incoherent, so it's difficult to figure out what the heck you mean particularly when you are confusing so many things together.


I have no idea where you get that. I'm just attempting to explain the subject, briefly.



No it doesn't. In an unbalanced circuit, one leg is ground. There is no common noise possible so there is no noise cancellation. How can it cancel out in an unbalanced circuit? The answer is that it can't, and that it doesn't, and that's why twisted pair doesn't do you a damn bit of good unless the circuit is balanced.

As for the links, I'm not sure what it is you are referring to that supports your idea that twisting the pair together somehow reduces noise by and of itself. It doesn't. It only helps if it is a balanced line. The Wikipedia article, rough as it is, does an alright job of explaining this. If you have an unbalanced line, there won't be any difference if you have an untwisted pair or a twisted pair, because the twist is only advantageous for common mode noise rejection which obviously only can occur in a balanced line.



I don't understand what you mean by this question. Do you mean too much resistance to ground? I'm not sure the relevance of what you are asking here.


Again, what? What has impedance modulated by noise? This makes no sense at all.


Okay...?


What links? What reason? You haven't even said anything that makes sense! The reason you're going around and around is because you're not constructing any kind of linear point here.

I fail to see why this topic is so difficult for you to understand. The pair twist only exists to make sure that noise is induced equally on both conductors, and the only reason this is beneficial is if it's a balanced line so it can cancel out. If it's not balanced, well then obviously is isn't going to cancel out is it! So the twist has no advantage at all! That's all I've been saying since page one, and apparently you can't accept this very simple premise. That's why you almost never see unshielded twisted pairs in anything but balanced lines, or for higher level signals where noise is not a concern.

And in the words of Stephen Lampen of Belden:

LOL...you're the 'expert'.


Good of you to finally admit it

I never thought there would be so much confusion and misinformation floating around about balanced pairs, unbalanced lines and balun systems.

First, as several folks correctly stated baluns are available to convert any signal type from audio to baseband video to RF to digital from one type of connection/transmission format to another. Unbalanced to balanced and back again.

Baluns were NEVER solely in the domain of 300 hm to 75 ohm RF antenna cabling. Baluns are nothing more than transformers with the primary and secondary windings connected differently with reference to signal ground.

One winding has one end of its coil tied to a signal common (not necessarily electrical ground) the other is the phase end which connects to the active circuitry I/O. The other winding has neither side of the coil tied directly to the signal common. The secondary coil does not NEED a common or ground reference to function.

The structure of these coils varies according to the signal source, bandwidth, impedance, frequency, and amplitude. It can be a ferrite donut or iron (steel) laminated core.

No matter what the signal source, the concept of a balun is the same.

Almost 50 years ago. Bogen sold a small balun transformer called the WMT-1. It had an RCA male cable on one side of a small metal box and screw terminals on the other. It was used to connect a Hi-z single ended (unbalanced) bridging signal from one amp, through a UTP cable to the same configuration on the other end. It worked fine for thousands of installs.

It sounds like a 50 year old, simple gadget would easily fill the bill for the OP.

I always thought "transformers" where always powered? Baluns are not powered. Of course I dont not care one bit about any of the discussion. I just know they work.

No definitely not. All a transformer is really is a pair of coils, in its simplest conception.

I figured that after reading some of the dicussion....never thought much about it, I have a very simplistic view of transformers.