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In Reply to: Twisted pair works bigtime in 'unbalanced' signal transfer. (long) posted by cheap-Jack on April 30, 2007 at 09:08:12:
Jack, your discussion of shielding misses my point that *unshielded* twisted pairs are not nearly as effective as we might hope in an unbalanced system. You are correct that twisting send and return conductors minimizes the loop area, thus minimizing inductive coupling, but it does nothing for capacitive coupling in an *unbalanced* system.A balanced system is one where both conductors see the same impedance to ground. They both pick up the same noise in the same phase; the noise is all common mode. When those two conductors are applied to a differential amplifier (or a transformer with an ungrounded primary) the common mode noise is rejected or 'canceled.'
If one of the wires is connected directly to ground it picks up virtually no noise while the signal carrying wire picks up plenty. In this case the noise is not common mode. It is differential mode and cannot be distinguished from the 'good' signal. It gets amplified right along with the music.
You are correct that balanced lines have a long history. My understanding (could be wrong) is that it started with telephone lines. They have always been unshielded twisted pairs. They have always been balanced and originally made use of transformers at both ends of the line. When was the last time you heard any 60Hz hum on your telephone even though the signal traveled dozens or hundreds or thousands of miles over unshielded wire sharing the same poles with power lines? If the system were not balanced you would probably hear nothing but hum. (Ok, phone systems are also bandwidth limited; they don't go down to 60Hz anyway, but still.)
"Since you've brought up the link of UTP. All LAN cables, e.g. Cat5e or Cat6 are U are UTPs - Unshielded Twisted Pairs."
Exactly. And the computer networks for which they are intended are balanced systems. If they were unbalanced they would not work without shielding. In fact, they probably wouldn't work very well even with shielding. Certainly they wouldn't work with many lines bundled together; each would require its own shield.
At the risk of being tedious, I'll repeat it one more time: noise suppression with unshielded twisted pairs is seen in balanced systems, but is almost entirely lost in unbalanced systems like a single ended amplifier.
Follow Ups:
I think we missed the memo. It appears the laws of physics do not apply to audiophools. Heck I am guilty at times. I even admit to twisting wires and an occasional kiwame:)Hmmm....is an IDE hard drive's data stream un-balanced? Maybe we need a ribbon cable with a ground between signal conductors (we can't use coax...too Jones'y). Why is it so many are trying everything and anything other than proven solutions from other areas? Sure it is cool to be different but pissing into the wind doesn't float my boat.
I guess my tolerance level for ripple reducing diodes and low DCR and multiple runs of 10-gauge wire for a 12au7 drawing less than 1ma is dwindling. I won't mention fruit.
Perhaps a 6 pack of Guinness stout and Bass ale along with some stimulating conversation will fortify me.
Russ, if we ever find ourselves within range, I'll gladly accept your beer, and buy more until my money runs out.I'm not sure about the IDE hard drive. Long ago I did put a scope probe on the data bus of a PC for fun. I was amazed at the amount of noise and wondered how the hell the thing could possibly work at all.
As for audiofoolishness, I've tried plenty of stuff that would make some experts giggle. I am a believer in the laws of physics. That they are 'out there,' immutable and knowable. I also understand that being knowable and being known are two entirely different things. OK, that's too deep. Let's just say that ripple reducing diodes are not high on my list of things to try... :)
Nahhh.....heck that is a given in my book.Long ago I saw a pic with a cat in a box with a vial of deadly gas on a string under an open flame. Moral was if you took a look and the string was intact and cat alive it proved squat cuz next second cat could be dead. Once dead he was always dead but alive was temporary.
I see knowledge and "truth" in the same way. Something to be used for what it is until it becomes "dead" due to new info. And we ain't even got to politics and religion yet:) Better get another round!
Heck I got an early start. Retirement party for a guy I worked closely with for the past 22 years. I will sorely miss being able to bounce ideas off his thick, but solid and conservative head. A guy that in regular life I wouldn't normally get to know but in the work setting the mutual respect lead to a friendship I will miss. Okay now That is too deep!
I know exactly what you mean. Some of the best and most interesting conversations I've had are with people that hold a completely different position. But, it is absolutely essential that they can at least understand what you are saying and provide reasonable, intelligent rebuttal.Many years ago I regularly hitchhiked between Buffalo and Rochester, NY. It was not uncommon to get picked up by a Jehovah's Witness. Talking with them was fun for only about 3 minutes ....
Hi.I never dispute about the effectiveness of a balanced signal transfer system. You started it which is out of the topic.
If you want to discuss further on a balance system, why not start a new thread & I would be more than happy to entertain you. Is it the appropriate way to voice out your points, which are technically valid?
If you want to be really hepful, why not reply to strictly to the poster's question like I did, instead of diverting into something else?
c-J
PS: Who is missing what? Have I ever claimed unbalanced signal transfer is AS good as a balanced system? Never.
Both of my posts had a single message. In the second post I repeated the message several times and explained it as carefully as is reasonable here. Just one message. No mixed fruit. Do you know what that message is? Can you state it in a single sentence? ('Balanced is better than SE' is *NOT* the message.)Frankly, I find it a tedious waste of my time that I should have to defend myself this way. For that matter, it's a tedious waste of time for everyone that reads this thread this far.
You seem to invest a tremendous amount of effort attempting to discredit me, all with the final goal of proving that you were right all along. Your usual tactic (might be unintentional) is to wander off-point listing uncountable irrelevant facts 'quoted' from unreferenced technical papers, then finally claim that I am talking apples and oranges; that you were talking about something else all along. I've been talking about only one thing and I've stuck carefully to that. If you see a fruit salad in front of you it's because you made it yourself.
I have a dream: one day you'll read one of my posts and respond with something like "OK, I see what you mean..." I don't know if you are incapable of it (perhaps literally incapable of understanding) or simply unwilling as a matter of pride. Perhaps both. But I do not expect my dream to ever come true.
Hi.Sorry, too bad if it sounded I intended to discredit you? Give me one decent reason why I would want to play games as such.
I only want to point out you, like any readers here, should play rule of posting - in topic. It was YOU who jumped in the discussion with something else, technically irrelevant. Not ME who sticks its nose into your business with something out-of-topic.
So who seems to be making "a tremenous effort attempting to discredit" whom? You or me?
Surely you have read what Kurt just posted - up-to-the-point reply to the original poster's question re shielding or not while clarifying the balanced signal system which you tried so hard to explain?
While I seem to have owned you some kind words of appreciation on you efforts you've made to explain your points, be it right or wrong regardless, I am very happy to share with my balanced signal transfer knowledge with you in a SEPERATE thread.
NO hard feeling please.
Jack, I apologize if I was too personal. I'd rather avoid being personal if possible, but I have to be honest and say that you make it very, very difficult.As for your charge that my discussion was off topic, I find that bewildering. If it's true that you have not been trying to misdirect the jury, then it must also be true that you simply do not see the relevance of what I was saying. That is unfortunate for you.
It pains me to have to explain myself (again, still): you suggested that unshielded twisted pair works "big time" with single ended circuits. I brought balanced/differential circuits into the discussion to explain that these circuits are where twisted pairs are intended to be used, that this is where the tremendous benefit of noise suppression is found (without shielding.) It is necessary to understand how that benefit is realized in balanced/differential systems to understand why it is not realized in single ended systems.
The fact that you may be incapable of seeing the relevance is unfortunate for you, and ultimately unfortunate for the rest of us too. I'll try to avoid saying anything more personal about you, though it is very, very tempting.
'he twists and turns like a twisty turny thing' Rowan Atkinson in Blackadder the 3rd . Applies to your little 'fruitbowl' outbursts , do a search on the archive and you'll see that you use this as an arguement continually . There is a very easy way out of this , a real man with real knowledge would :Just admit they're wrong !!!!!
ps I could easily discredit you with using the phrase 'up to the point' . It is very poor gramatical use of the English language if you could pardon my poor spelling . I would have thought that a degree educated expert (which you often claim to be) could do better
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read the thread pal . no twisting ot turning , finger-pointing or fruit please . You agreed with Kurt S who accepted he had made a mistake , therefore your attack on Dave C was unfounded . So 'be up to the point' and admit your mistake , only a 100lb weakling hung like a chinese mouse wouldn't
Hi.Be my guest, your no-name coward!!
Your stinky way of positng reads pretty similar to that shitty German character who just rampaged Propeller Head Plaza out of the blue.
What moniker you wanted to change tomorrow? You German coward!!!
All the time I was talking about unbalanced signal transfer. I agreed to Kurt's statement on balanced signal transfer needs a CT as Kurt responded to Dave Cigna.
Read the textbooks about balanced signal transfer before you ever wanted to comment. Empty talks bring you nowhere.
I never mentioned differential but Dave did.
c-J
PS: Would the Bored please watch out for this insane character here.
c-J, are you in China?
To be honest with you , your behaviour is quite disturbing and rather odd . My post was only pointing out your own inadequacies with a spot of humorThe above post starts off with a bit of name calling , followed by swearing , then accusations , then another relating to my location (which is not Germany) . Then an insult . Then a threat . You got the wrong person , sort the facts out then sort your life out . I think you owe me an apology
Thanks !!!
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