Balanced & Unbalanced Outputs (audio)

[Speedskater]

On unbalanced RCA interconnects and common mode problems.
This Henry Ott note covers it.
http://www.hottconsultants.com/pdf_files/Audio Interconnections.pdf

In short the big problem is 'common-impedance coupling' and the solution is a coax with a very heavy braided shield.

 

[highfigh]

You are distorting the facts. [pun intended] Balanced circuits, which are interconnected by balanced cables, use split phase signals that when terminated in a combining circuit cancel the common noise carried in the two opposite phase halves of the signal. A shield is a different thing altogether, and works on the same principal as a Faraday cage. The balanced interconnects I use (from Blue Jeans) are based on Belden 1800F cable, which includes a braided shield, so you get both a shield to reduce interference, and then common mode cancellation to reduce added transmission noise. Use balanced connections from the source through all balanced circuits to a balanced amp, and you get end-to-end common mode cancellation.

I know this- you should have determined that by the rest of my post. The whole reason for the way shielded twisted pair is used for LowZ balanced is to keep the audio signal separate from the shield and so the shield can act as you wrote- the shield blocks noise from the outside and the twisted pair cancels noise via inductive coupling and I have posted the same as you did in your last comment many times in these discussions.

If cables with XLR are used from preamp to power amp, the system still benefits from common mode noise reduction but it doesn't have the benefit of the whole signal path using them and if the cable has a drain wire and it's connected to Pin 1, it's possible to have a ground loop, which is the reason I replaced the cables in one system with unbalanced.

The cables I use are Canare L-4E6S with braided shield, partially because I live near an antenna farm for local TV and radio and my supplier had a better price for this than the Belden. I like Belden- my customers give me weird looks when I tell the kind of cable I use, but I sleep better knowing that I didn't scam someone.

 

[DubPlate]

I wagered a doughnut on the outcome of that thread as soon as it started. I went ahead and ate my doughnut because there wasn't too much doubt as to how that was going to come out.

Irv could also weigh in with the guy who bought $4,000 worth of gear and did not know how to plug any of it in and ended up not using $1K of it and having to go back and buy more gear. Or, well, I suppose that's enough for one day.

If Irv is an engineer, then perhaps he can appreciate this life metaphor regarding problem solving. When examining a problem, there are glass half full guys and glass half empty guys. An engineers response is typically "the glass is neither half empty or half full. The glass is twice as big as it needs to be".

badda bump.

Ouch!

 

[Speedskater]

In a correctly wired balanced interconnect system, XLR pin #1 is only the shield and it's connected directly to the chassis. It is not part of the audio signal. There should be no hum caused by connecting the shield (XLR pin #1) to the chassis. This was tested way back in 1994/95 when they were developing the standard, AES48.

 

[HTfreak2004]

It's possible to add better quality wires to a system and make it worse. Not because the wire is to blame but because the rest of the component internals aren't supporting the quality. Basically I mean you can take a system that is maxed out quality wise for it's fair market value and try to add speakers that are built with better components and end up with poor quality sound. Reason being you can make a poor quality speaker sound it's best with quality equipment however the opposite is true when you mate well built quality speakers with poor quality equipment. Everything in the chain must support the other or the weakest link spoils the show. The source recording must be the highest quality, the reading player must be capable of reading it and minimizing any of its own imperfections upon the source material. The wire of choice for power and clean dedicated power should be used. The interconnects should all support the least amount of signal loss and have the least potential to pick up external feedback from other power sources. The list goes on and on. Choosing to add quality wires to improve sound quality shouldn't be over looked. But was is a high quality wire? An expensive one? No. It is a wire that supports the other components in your system level of wiring. The same materials with the same electrical properties and characteristic behaviours. You cannot mask a weak link in the chain when it's under Load and that is the same with the wires within a HT setup. Every wire counts. I know that is way to microscopic to view a system but it is unrealistic. I would like to add one last point to this rant. Some days your system will blow you away and other days it will make you second guess why you chose it. That's because you listen to to much audio in to many settings and that is way to much material to really know what is causing the like or dislike. Then when you listen to it again on your own system it sounds all together different again. Take your setup put it in another room or move it a bit in the room it's in a again a new experience with the same source material. No system can play all source materials in one setting correctly. Same with wires. They are meant for certain setups and not all and a lot are no better than the other brands and even more are garbage!


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[Bucknekked]

It's possible to add better quality wires to a system and make it worse. Not because the wire is to blame but because the rest of the component internals aren't supporting the quality. Basically I mean you can take a system that is maxed out quality wise for it's fair market value and try to add speakers that are built with better components and end up with poor quality sound.

Same with wires. They are meant for certain setups and not all and a lot are no better than the other brands and even more are garbage!

OK, being a newb to the forum and someone that primarily is here for the audio help, I was prepared to leave this thread alone. Its kinda taken a weird turn. But, that first sentence in your post just defies basic physics. I will let the audio engineers (real ones) chime in with the physics of why its simply not true, but geez louiz, I have never heard of anyone lousing up the sound of a system by adding better quality cables.

Fair market value is not an audio term I am familiar with. I wonder if there is an NRC test for FMV? I know I have an excel formulae for it I use all the time. Just didn't know it applied to audio.

That last sentence also defies my understanding of physics. You got me on the wires are meant for certain setups. I was not aware of that property. I have much to learn as a grasshopper in this great wide open field of audio.

 

[Irvrobinson]

It's possible to add better quality wires to a system and make it worse. Not because the wire is to blame but because the rest of the component internals aren't supporting the quality. Basically I mean you can take a system that is maxed out quality wise for it's fair market value and try to add speakers that are built with better components and end up with poor quality sound. Reason being you can make a poor quality speaker sound it's best with quality equipment however the opposite is true when you mate well built quality speakers with poor quality equipment. Everything in the chain must support the other or the weakest link spoils the show. The source recording must be the highest quality, the reading player must be capable of reading it and minimizing any of its own imperfections upon the source material. The wire of choice for power and clean dedicated power should be used. The interconnects should all support the least amount of signal loss and have the least potential to pick up external feedback from other power sources. The list goes on and on. Choosing to add quality wires to improve sound quality shouldn't be over looked. But was is a high quality wire? An expensive one? No. It is a wire that supports the other components in your system level of wiring. The same materials with the same electrical properties and characteristic behaviours. You cannot mask a weak link in the chain when it's under Load and that is the same with the wires within a HT setup. Every wire counts. I know that is way to microscopic to view a system but it is unrealistic. I would like to add one last point to this rant. Some days your system will blow you away and other days it will make you second guess why you chose it. That's because you listen to to much audio in to many settings and that is way to much material to really know what is causing the like or dislike. Then when you listen to it again on your own system it sounds all together different again. Take your setup put it in another room or move it a bit in the room it's in a again a new experience with the same source material. No system can play all source materials in one setting correctly. Same with wires. They are meant for certain setups and not all and a lot are no better than the other brands and even more are garbage!


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You typed all of this nonsense into an iPhone? That's impressive. The content, not so much.

 

[HTfreak2004]

If you use a wire that exposes flaws like a good system does with a crappy recording then you get my point on the quality wire making a poorly built systems flaws more audibly noticeable. Think about this for a moment. Most listeners are used to loud with distortion and when they hear the same volume played cleanly it sounds quieter. Distortion is hard on our ears and our Audio Equipment it also adds to a false perception of loud. If you can mask it under a wire rather than expose it it's less obvious. But once you expose its presence it's very distracting and annoyingly. So yes quality down the chain brings out the weakness further up the chain if you know what to listen for and have had some experience with your system for a few months. Every component in your system is electrical and is linked to one another through electrical connections internal and external. From personal experience I would suggest starting with wires under 50 dollars gain experience try some others and see what you learn but once you hit the performance ceiling of your system you won't know if you are getting the value you paid in the more expensive not necessarily higher quality wire. Always check the resistance and shielding properties of your wires and try to learn about the internal wiring of your components. You spent the money you should know what your getting instead of just the features!


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[vsound5150]

It's possible to add better quality wires to a system and make it worse. Not because the wire is to blame but because the rest of the component internals aren't supporting the quality.

Another grasshopper newb here (not you, me). On several occasions I've had old electronics eventually fail after installing a new replacement part. It was one of those head scratching moments and the only thought was similar to what you said mix matching old and new.

Long ago a co-worker let me borrow various low and high quality cables and "tip toes" to take home and test and see if I could hear the difference. When I returned the cables and told him I could hear the difference and what cables were my favorite, he couldn't stop laughing because it was the lower end cables I preferred. Maybe my audio equipment was junk (actually it was) compared to his. He was a huge audiophile but not me I was happy just playing a CD back in those days.

 

[HTfreak2004]

It's sad but true! Why don't HD TVs have s video or composite video? That's not a wire that supports HD. Just like a audio interconnect must support the audio and speaker wire must allow the current to flow with as little resistance as possible. Once the wire cannot support the current the resistance goes up and the sound quality goes down but if you allow more current to flow to good speakers say with less resistance wire it will allow you to hear more detail or more weaknesses in your components. So thanks for lending your experience with that!


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[MR.MAGOO]

Thanks for all the great feedback to my question. In a nutshell, I don't need to worry about major signal loss or RFI interference if I'm running speaker wires over 35 feet using unbalanced method? (12awg normal speaker wire).

 

[highfigh]

In a correctly wired balanced interconnect system, XLR pin #1 is only the shield and it's connected directly to the chassis. It is not part of the audio signal. There should be no hum caused by connecting the shield (XLR pin #1) to the chassis. This was tested way back in 1994/95 when they were developing the standard, AES48.

I would hardly consider 1994/95 to be 'way back'- that's very recent history WRT A/V equipment and the 'Pin 1 Problem' had been discussed and formalized for a long time before that paper came out. Also, that statement makes me feel old. Now get off my lawn!

However, if the shell of an XLR is connected to Pin 1, hum can and does occur. That's the reason for the switch that lifts a ground on some equipment. That wasn't a slight hum, either.

 

[highfigh]

It's possible to add better quality wires to a system and make it worse. Not because the wire is to blame but because the rest of the component internals aren't supporting the quality. Basically I mean you can take a system that is maxed out quality wise for it's fair market value and try to add speakers that are built with better components and end up with poor quality sound. Reason being you can make a poor quality speaker sound it's best with quality equipment however the opposite is true when you mate well built quality speakers with poor quality equipment. Everything in the chain must support the other or the weakest link spoils the show. The source recording must be the highest quality, the reading player must be capable of reading it and minimizing any of its own imperfections upon the source material. The wire of choice for power and clean dedicated power should be used. The interconnects should all support the least amount of signal loss and have the least potential to pick up external feedback from other power sources. The list goes on and on. Choosing to add quality wires to improve sound quality shouldn't be over looked. But was is a high quality wire? An expensive one? No. It is a wire that supports the other components in your system level of wiring. The same materials with the same electrical properties and characteristic behaviours. You cannot mask a weak link in the chain when it's under Load and that is the same with the wires within a HT setup. Every wire counts. I know that is way to microscopic to view a system but it is unrealistic. I would like to add one last point to this rant. Some days your system will blow you away and other days it will make you second guess why you chose it. That's because you listen to to much audio in to many settings and that is way to much material to really know what is causing the like or dislike. Then when you listen to it again on your own system it sounds all together different again. Take your setup put it in another room or move it a bit in the room it's in a again a new experience with the same source material. No system can play all source materials in one setting correctly. Same with wires. They are meant for certain setups and not all and a lot are no better than the other brands and even more are garbage!


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Nothing that's designed to operate in an audio or video system should come from a source device that can't be handled by the next piece in the signal path and no cable should introduce ANYTHING to the signal. Can a highly resistive/capacitive cable be used for a specific purpose? Absolutely, but if fidelity is the goal of the system, the ideal is "straight wire with gain" and that's impossible.

If the cable doesn't have inordinate resistive and capacitive characteristics, they shouldn't make much of a difference.

I would bet that if someone's system sounds great one day and doesn't on other days, it's because they were exposed to excessive noise levels, atmospheric changes, sinus problems or something like that, not because of some variation in their system. If any part of a system varies so much that it produces worse sound, it has a problem.

 

[slipperybidness]

Perhaps mechanical engineers are like that, but analog electrical engineers never want to fully deplete their loss budget, so they would see the extra space in the glass as headroom.

A scientist will tell you, it's half full of water and half full of air

But, I do like that "headroom" analogy!

 

[HTfreak2004]

I believe the point your trying to make isn't what my point was addressing. You said that no cable should introduce anything to the signal and I said the cable must support the higher quality component further up the audio chain. If it doesn't then you lose quality and if it is better than what's further up the chain towards source it may expose imperfections if you are used to another cable. I also said there is a lot of crap cables that won't be better than other cables such that you would notice any improvements. Besides more ppl don't usually know what is their weak link in the chain anyway. By the time they figure it out most of the time they usually are disappointed that the solution doesn't offer much change in quality. If you believe that source recordings are not the determining factor in whether you can make a high fidelity system sing to the heavens or raise the demons your sadly mistaken. And secondly if you believe that you can support the best player with lower quality parts down the chain to the speakers then go out and by some tapes and VHS movies and an MP3 player because it's not going to matter then your already convinced. As the saying goes: a man convinced against his will is of the same opinion still which are by the way a nickel a dozen because a dime would be to generous!


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[Speedskater]

I would hardly consider 1994/95 to be 'way back'- that's very recent history WRT A/V equipment and the 'Pin 1 Problem' had been discussed and formalized for a long time before that paper came out. Also, that statement makes me feel old. Now get off my lawn!

This is incorrect!
Neil Muncy first wrote about the problem in 1994/95 (see links), but the problem persisted a decade later even after the standard AES48 (2005) was written. In audiophile equipment the problem remained after two decades!

Pin 1 Revisited Neil Muncy called our attention to the Pin 1 problem (the improper termination of the shield of audio wiring to the circuit board rather than to the shielding enclosure) in his classic 1994 paper, reprinted in the June 1995 Journal of the AES. When he wrote his paper, most commercially available audio gear had pin 1 problems. It was, indeed, difficult to find equipment without it -- even the most prestigeous consoles had serious pin 1 problems! Over the next decade, the better manufacturers redesigned their products to correct their mistake, but sadly, many have not done so.
http://www.audiosystemsgroup.com/Pin_1_Revisited.pdf
http://www.audiosystemsgroup.com/Pin_1_Revisited_Part_2.pdf

However, if the shell of an XLR is connected to Pin 1, hum can and does occur. That's the reason for the switch that lifts a ground on some equipment. That wasn't a slight hum, either.

The only reason that the shell is not connected to pin #1 AES54, is because the shell can come in contact with metal that is not at shield potential in portable cables. From an interference point of view it's better to connect the shell.

 

[lovinthehd]

Thanks for all the great feedback to my question. In a nutshell, I don't need to worry about major signal loss or RFI interference if I'm running speaker wires over 35 feet using unbalanced method? (12awg normal speaker wire).

If your question was about speaker wire, it isn't unbalanced or balanced nor is it particularly subject to RFI. Try this table or this calculator

 

[gzubeck]

Another grasshopper newb here (not you, me). On several occasions I've had old electronics eventually fail after installing a new replacement part. It was one of those head scratching moments and the only thought was similar to what you said mix matching old and new.

Long ago a co-worker let me borrow various low and high quality cables and "tip toes" to take home and test and see if I could hear the difference. When I returned the cables and told him I could hear the difference and what cables were my favorite, he couldn't stop laughing because it was the lower end cables I preferred. Maybe my audio equipment was junk (actually it was) compared to his. He was a huge audiophile but not me I was happy just playing a CD back in those days.

Cables Smables...

Either that or he had you borrow his cables to confirm his suspicions...that cables make a difference but not justify the additional cost. Dont laugh but I tried some heavy duty 10 gauge outdoor lighting cable from home depot for .97 cents a foot with what looked like pure heavy copper. Its still in my system. Im using $5 dollar audtek rca cables from parts express that im quite happy with. the rest of my system is pretty good with an emotiva a300 amp, schiit 4490 dac, and sys preamp. my digital system sounds very good.

 

[lovinthehd]

Long ago a co-worker let me borrow various low and high quality cables and "tip toes" to take home and test and see if I could hear the difference. When I returned the cables and told him I could hear the difference and what cables were my favorite, he couldn't stop laughing because it was the lower end cables I preferred. Maybe my audio equipment was junk (actually it was) compared to his. He was a huge audiophile but not me I was happy just playing a CD back in those days.

I'd have laughed at your co-worker for the cable nonsense. Hopefully you didn't buy into it. Was he particularly overweight or very tall or? (the huge audiophile part ) Definition of audiophile is one who is enthusiastic about high fidelity audio reproduction....

 

[gzubeck]

Thanks for all the great feedback to my question. In a nutshell, I don't need to worry about major signal loss or RFI interference if I'm running speaker wires over 35 feet using unbalanced method? (12awg normal speaker wire).

That might not be true...if your going to run speaker wire that long you might want shield speaker cable. also 35 feet or 11+ meters might add some inductance and resistence. the 12 gauge should be pretty good for most circumstances but I think some in wall cable is shielded. check it out first before you buy long lengths of cable first.