Balanced vs. Unbalanced Inputs


I am trying to upgrade to a differentially balanced phono stage to compliment my Pass XP-22 pre and Pass X250.8 amp so as to minimize long cable artifacts and benefit from CMR. I do understand the it is the circuitry and not the input connection that determines wether a signal is balanced or not. I am looking at both a Pass XP-27 and AR Phono 3SE as possible options. Both have RCA inputs plus a ground post only. No XLR inputs. 

As far as my understanding goes, a balanced cable must have 2 signal conductors, a hot (+) and a cold (-) PLUS a ground for EACH channel. So, I sent an email to Pass Labs as follows:  

 ".... I want to confirm that there are TWO signal conductors PLUS a ground for each channel. Specifically, on each of     the RCA inputs, do the center pins and the shields carry the hot (+) and cold (-) signals respectively while the grounding wire/grounding post becomes the tone arm/turntable chassis ground connection common to BOTH channels? "

This was the response:
     "No. RCA shield and ground lug are contiguous connections."

But on the pass website is the following:
     "In order to minimize ground loop issues Pass Labs never manufactures equipment with signal ground and chassis ground contiguous."

When I email Linn about their pseudo balanced  LP12 T cable they responded with:
     "All Linn arm cables are terminated with a 5 pin DIN connector with the center pin being arm ground, which on an LP12 is also used as the chassis ground.  This is separate from the left and right channel grounds and hots which are on the other 4 pins."

Again, there is no (+) signal to be superimposed with an inverted (-) signal separate from ground for CMR. I Do have a technical background but I am not well versed on circuit design so please forgive my ignorance. I did get some very helpful advice from a member here, however, the further I inquired with the manufacturers the more confusing it became. As of now I am wary about emailing AR for fear of even more confusion. If anyone has any advice on how to proceed I would really appreciate it. Thank you all so much.

Bruce
brskie
RCA connectors can't carry a balanced signal. You need to use cables with XLR connectors to support balanced. 
If your looking for confusion you came to the right place.. Get a hold of PASS and talk to them.. Call Nelson Pass get his number at First Watt and ask HIM.. It’s been a few years, he has always been available for his products in one form or another.. I’ve seen him weigh in on a few DIY treads just to help out..

You know horses mouth stuff..

Regards
This was the response:
     "No. RCA shield and ground lug are contiguous connections."
In an unbalanced (RCA) cable there are only 2 wires, a signal and a ground (which acts as the return signal). The cable has a shield wrapped around the conductors, which can pick up interference which results in noise.

In balanced cables there are 3 wires in the cable, 2 for signal and one ground. There is a shield wrapped around them. The two signal wires carry a sine wave which is 180 degrees out of phase from each other. When this cable is connected to a fully balanced component, the 2 signals are put back in phase.



But on the pass website is the following:
"In order to minimize ground loop issues Pass Labs never manufactures equipment with signal ground and chassis ground contiguous."

This statement is unrelated to the balanced vs. single-ended (unbalanced) operation. Pass is referring to the grounding of a component. The signal ground is the end point for the cable that is plugged into the component, whether it is balanced or unbalanced. The designer grounds this wire to a designated area inside the unit.
He refers to chassis ground which is more commonly known as safety ground or earth ground. This is the wire that travels all the way back to the ground in the service panel where it connects to the neutral wire.
Safety ground is attached to the metal chassis and runs down the power cord (the 3rd prong on the PC connector) 
for safety reasons such as a shock to the body since current is flowing through the components and cables.
In a proper design, such as a Pass amp, the signal ground and the safety ground never meet.



I looked at the Pass phonostage and it is designed for an unbalanced connection from the turntable. Your LP12 is single-ended. The ground screw on all phonostages is for the ground wire from the TT to prevent noise and hum. There are balanced outputs to go to your preamp.
I checked the AR and it is the same unbalanced design. Outputs are SE and balanced. Again, the LP12 is not balanced, it is single-ended like 90% of turntables.


@lowrider57 
Thanks so much. Therefore, according to your response and my research, each of these phono stages must somehow convert an unbalanced incoming signal into a balanced outgoing signal internally. This is what was so confusing to me. I thought that the balanced 4 pin signal from a cartridge had to remain balanced throughout the electronics. I didn't know it could be converted to unbalanced at the tonearm DIN connection and then back to balanced again inside the phono stage.
Again, thank you for your very helpful response.

Bruce
lowrider57
... the Pass phonostage and it is designed for an unbalanced connection from the turntable ...
No, this is mistaken. You’re confused - its use of RCA connectors doesn’t mean the inputs are unbalanced.
Your LP12 is single-ended.
Again, you’re confused. A turntable by itself is neither balanced nor unbalanced.
I checked the AR and it is the same unbalanced design. Outputs are SE and balanced.
No, the ARC Ref Phono is a fully balanced, differential design.

A phono cartridge is inherently balanced; that is, it has separate positive and negative for each channel. If these are fed to a fully differential phono preamp such as the ARC, then you are balanced from phono cartridge to the phono preamp’s balanced outputs. The turntable really has nothing to do with it.
Again, the LP12 is not balanced, it is single-ended like 90% of turntables.
Completely mistaken.
Technically a phono cartridge is "floating" which means it's neither balanced or single ended. It can be wired either way but the reason there are so few balanced turntables/phono stages is that there is diminishing return on splitting the signal to make it balanced, particularly when the signal from a cartridge is already so weak. 

This is all theoretical. Best thing to do is take a listen of you can and see if you hear a difference. Me experience is not but yours may be different. For other compnents like a DAC there is often marked benefit. Just not usually from a TT.


rmdmoore
Technically a phono cartridge is "floating" which means it’s neither balanced or single ended. It can be wired either way ...
I am surprised that there remains so much confusion on this. A phono cartridge is inherently balanced. That it can be wired unbalanced doesn’t negate that. (Of course, if you connect it to a single-ended phono stage, then you're giving up the potential benefits of the cartridge's balanced construction.)
... the reason there are so few balanced turntables/phono stages is that there is diminishing return on splitting the signal to make it balanced, particularly when the signal from a cartridge is already so weak.
No, I think manufacturing cost explains why we don’t see more balanced phono stages. Keeping a phono cartridge balanced offers multiple advantages, not the least of which is CMR, which is of particular value given the low signal level of the phono cartridge output.

There is no such thing as a "balanced" or "unbalanced" turntable unless, arguably, you’re referring to a turntable with a built-in phono stage.
@cleeds
 So this is the crux of my delima. Since the AR Phono 3SE is a fully differential phono stage, and, since it ONLY has RCA inputs and a ground post then:
      On each of the RCA inputs, do the center pins and the shields carry the hot (+) and cold (-) signals respectively while the grounding wire/grounding post becomes the tone arm/turntable chassis ground connection common to BOTH channels?

This is the only way I can logically assume that the input to the ARC phono stage occurs since there are only 2 connections on an RCA to begin with. Unlike an XLR that has 3 connections.
So then, does Linn's email response:
   
"All Linn arm cables are terminated with a 5 pin DIN connector with the center pin being arm ground, which on an LP12 is also used as the chassis ground.  This is separate from the left and right channel grounds and hots which are on the other 4 pins."

mean that the signal going from the DIN to the phono stage IS balanced? Or, do I have to assume that I would not be able to use a factory Linn tonearm cable and have to arrange for some kind of bespoke wiring in my arm so as to feed the ARC phono stage a balanced signal to begin with???
I can see why there is so much confusion around this topic of balanced/unbalanced signals with the unwillingness of audio companies to follow a strict set of standards.
Thank you for taking the time to respond. I really do appreciate it very much @cleeds 

brskie
... Since the AR Phono 3SE is a fully differential phono stage, and, since it ONLY has RCA inputs and a ground post then:
      On each of the RCA inputs, do the center pins and the shields carry the hot (+) and cold (-) signals respectively ...
Yes.
... while the grounding wire/grounding post becomes the tone arm/turntable chassis ground connection common to BOTH channels?
No. The ground is independent and not common to either channel.
@cleeds 
So I just have to figure out my tonearm wiring to get the balanced signal into the ARC RCAs.
Thank you again for so freely giving your help.

Bruce
RCA connectors can't carry a balanced signal. You need to use cables with XLR connectors to support balanced.
This isn't entirely true. If the sleeve connection is shielded in the interconnect cable independantly of ground, and if the ground connection is in no way allowed to contact the sleeve, then the RCA can transmit a balanced signal, with the only issue being its slightly more capable of hum pickup at the connector itself. In practice this isn't an issue unless you touch it.
Technically a phono cartridge is "floating" which means it's neither balanced or single ended. It can be wired either way but the reason there are so few balanced turntables/phono stages is that there is diminishing return on splitting the signal to make it balanced, particularly when the signal from a cartridge is already so weak. 
This statement is false. A floating inductor like a cartridge is in fact a balanced source. In order to run it single-ended, you have to do something with the grounding system, which is that weird 3rd ground wire that no other single-ended source seems to need. With a balanced source, ground is ignored (the ground wire, which is also the tonearm tube); there's no connection between the source and ground.

You don't have to 'split' the signal. In a balanced system, the floating signal is applied to the inverting and non-inverting inputs of the amplifier or preamplifier. Again, ground is ignored- its only used for shielding and there is no signal current in it.

A 5-pin DIN connector like on the Linn is a balanced connection. Pin 3 of the connectors becomes the shield of both channels and ties to pin 1 of the XLRs at the other end of the tonearm cable.

I can see why there is so much confusion around this topic of balanced/unbalanced signals with the unwillingness of audio companies to follow a strict set of standards.
@brskie  When we made the world's first balanced line preamp (for home use) back in 1989, it didn't occur to us that we should do anything other than meet the standards of balanced line operation, known as AES48. But as balanced line became a thing in high end audio, we found that almost everyone was ignoring or were unaware of the standard. So there is a *ton* of confusion about this topic. 
... while the grounding wire/grounding post becomes the tone arm/turntable chassis ground connection common to BOTH channels?
No. The ground is independent and not common to either channel. 
This is begging for clarification! The ground (shield of both channels of the interconnect cable, pin 3 of the DIN connector) is grounded to the chassis of the phono preamp. In the case of the ARC, it should not contact the sleeve of the RCA connection in any way. But obviously since its tying to chassis, its by definition common to both channels.


@atmasphere 
Hello again. In your response:
"...A 5-pin DIN connector like on the Linn is a balanced connection. Pin 3 of the connectors becomes the shield of both channels and ties to pin 1 of the XLRs at the other end of the tonearm cable..."

However, the Linn arm cable terminates with RCA not XLR.

Then you said:
... while the grounding wire/grounding post becomes the tone arm/turntable chassis ground connection common to BOTH channels?
No. The ground is independent and not common to either channel.
"This is begging for clarification! The ground (shield of both channels of the interconnect cable, pin 3 of the DIN connector) is grounded to the chassis of the phono preamp. In the case of the ARC, it should not contact the sleeve of the RCA connection in any way. But obviously since its tying to chassis, its by definition common to both channels. "

So does this mean that to send a balanced signal to the phono pre I should connect that "weird 3rd ground wire" to the ground post on the ARC, or, should I ignore it and tape over the end so it won't ground to the chassis of some component.

Thanks again Ralph for all you give to everyone in this community.

Bruce
"...A 5-pin DIN connector like on the Linn is a balanced connection. Pin 3 of the connectors becomes the shield of both channels and ties to pin 1 of the XLRs at the other end of the tonearm cable..."

However, the Linn arm cable terminates with RCA not XLR.
@brskie
Yes. Linn chose to use RCAs and bring out pin 3 as a separate connection (the ground wire). But if you run balanced, there is no ground wire because it is ground, which is pin 1 of the XLRs, which are tied to pin 3 of the DIN connector. IOW, you merely change out the interconnect cable.
The ground (shield of both channels of the interconnect cable, pin 3 of the DIN connector) is grounded to the chassis of the phono preamp. In the case of the ARC, it should not contact the sleeve of the RCA connection in any way. But obviously since its tying to chassis, its by definition common to both channels. "

So does this mean that to send a balanced signal to the phono pre I should connect that "weird 3rd ground wire" to the ground post on the ARC, or, should I ignore it and tape over the end so it won't ground to the chassis of some component.

Since ARC chose to use a non-standard connection (an RCA instead of XLR; this was done so you could just plug in a regular single-ended connection and it would still work) the cable you need is a bit confusing.


At the tonearm end its a DIN connection. The cable for one channel needs to have a shield around a twisted pair. The twisted pair will carry the signal. They will tie to the RCA connector at the output. The shield ties to pin 3 of the DIN connector and will have to have a wire attached to it at the other end of the cable with a little bit of length, so it can be tied to the chassis ground post of the preamp. The other channel should be the same thing (so this makes the pin 3 connection of the DIN a bit tricky). The two wires at the output end are then tied together and a lug installed. The lug is then attached to the ground post. Care must be taken in the construction of this cable so that the shield is not able to come in contact with the sleeve of the RCA connectors and also does not tie to anything but pin 3 at the DIN end of the cable. If you have a cable made up like this it will be plug and play with no buzz issues, as long as nothing is touching the RCA connectors when they are plugged in.


We put XLR connections at the input of our phono section so that the end user would be forced to set up the cable correctly. There is no need for an RCA connection if your phono section is balanced; the only reason ARC did this was to make dealers happy so they wouldn't have to change their interconnect cable for the tonearm. The downside of this is that the most important place in the entire system to get the cable right is arguably the tonearm cable- anything that goes wrong at that point can't be made up for downstream!


The whole point of balanced cable operation is to avoid interconnect cable interaction with the sound of the system and if the tenants of the balanced system are followed, it does this very well. This means that to sound right, the cable does not have to be expensive, it simply has to be correct!

WOW
Thank you Ralph for the detail here. Now I Understand the mechanics, and I believe, the theory too. This is the clearest explanation I have found in a week of searching.
Be well, stay safe and Better New Year everyone !

Bruce
Good ol' Ralph,
Always the best information in clear understandable English.
B
Where is the empirical evidence of improvement using balanced connections?  Any?  Any at all?  Oh, that's right, because there is none.  
Turntable is RCA...what are you on about?  Hello 👋🏻 
Post removed 
The stumbling block here is that the signal "ground" (return) and the (arm, chassis) shield are different. Always.
As Moncrieff recommended 35 years ago put your single ended cables in a mesh tube attached to pin 3 and the amps chassis.
Over and out.
The whole point of balanced cable operation is to avoid interconnect cable interaction with the sound of the system and if the tenants of the balanced system are followed, it does this very well. This means that to sound right, the cable does not have to be expensive, it simply has to be correct!


Could you clarify this, because in my mind, the point of balanced is, and has always been common mode noise rejection.  Good cable construction will of course lead to consistency of noise on both cables ensuring common mode rejection.

Now w.r.t. studio balanced connections, i.e. AES compliant, that is not just about balanced, but a drive/load standard that is low enough impedance to dominate over cable parameters.


Technically a phono cartridge is "floating" which means it's neither balanced or single ended. It can be wired either way
This statement is false. A floating inductor like a cartridge is in fact a balanced source.


No, that statement is quite true. A floating source is not the same as a differential source. It would only be truly differential if you center tapped it and connected the shield to the center tap, such that coupling to the cable shield is similar for both conductors. That is not the case for a cartridge.



but the reason there are so few balanced turntables/phono stages is that there is diminishing return on splitting the signal to make it balanced, particularly when the signal from a cartridge is already so weak.


I disagree with the diminishing returns as the two channels are completely separate loops, hence if you connect them to the same ground (single ended), then you loose the benefits of independent floating loops and reduce common mode rejection.

And than, we gonna “hear “the difference  between the 2: for me RCA is more open: good balance, beautiful placement , detailed and holographic. XLR: gives also a good balance, placement:okay, but the openness is less: “flatter” compared to RCA.  Conclusion: I only used RCA. ( my system: CEC cd-player, Auralic streamer, Metronome Technologie C6 (dac), Daniël Hertz M6L ( préamp) Wavac MD 805 m ( monoblocks) and Ilumnia Magister (speakers)
Balanced vs. Unbalanced Inputs
First off you need to ascertain if they are "real" balanced outputs or "real" balanced inputs.

As many outputs are really SE, and an opamp chucked on to it to give pseudo balanced output, in this case your better to listen to the SE not the balanced.

Same goes for inputs on many amplifiers they are SE input circuitry, and they again just chuck an opamp onto it so you can have balanced, again in this case the SE will sound better also.

Now for the tricky bit, you can only find this out if you know what your looking at, look inside at the input board section, or see circuit diagrams. Because no-way will they state this, in their literature

Cheers George
.
Goodness me.  Opinions here are diametrically opposed on a question that should be straightforward.  The OP says he understands now but if that is the case then he is smarter than I am.

I had believed that running phono fully balanced brings a 6dB noise floor reduction and thus is very desirable given the very low level signals involved.  Having read the thread carefully and re-read it, I no longer clear that a phono output can even be run single ended (because of the cartridge 'floating' idea expressed in two posts).  Nor yet has any view been expressed here as to the respective SQ benefits of balanced vs single-ended operation  (Possibly premature as it has not been agreed what balanced operation is or whether it is possible).

I think I would be a great idea to ask the the great phono cartridge and phono amp designers to clear this up - hopefully they might all agree.  Question: precisely how are cartridge and turntable wired to the phono amp to obtain fully balanced operation?

Also it would be highly instructive to listen to the same system wired single-ended and then fully-balanced and to take noise measurements of each.
I cannot believe the arguments phrased here because of a lack of a simple circuit diagram and a bit of simple circuit knowledge.
If you wish to know the difference between a single ended circuit and a differential circuit, AND the relative grounding difference, you need a simple CIRCUIT DIAGRAM and knowledge about how circuits and especially SHIELDED circuits work. The word "ground" should be defined MUCH better for people who are "wire nuts," i.e., those who follow WORDS (OMG!) better than circuit diagrams. de KQ2E
Nice of you @nitroxpro to advance the conversation with circuit diagrams and your advanced knowledge of simple circuits.
Where is the empirical evidence of improvement using balanced connections? Any? Any at all? Oh, that's right, because there is none.  
Actually there is and its historical. So here is the history: Before balanced lines were developed, a long distance phone call was really only good to the other side of nearly any given state, and you had to be prepared to yell at the top of your voice to be heard. When balanced lines were introduced, this made transcontinental phone calls possible with greater intelligibility. The recording industry was quick to adapt the technology (in the late 1940s and this is one of the key technologies besides the invention of the tape recorder that ushered in the age of high fidelity.
The whole point of balanced cable operation is to avoid interconnect cable interaction with the sound of the system and if the tenants of the balanced system are followed, it does this very well. This means that to sound right, the cable does not have to be expensive, it simply has to be correct!


Could you clarify this, because in my mind, the point of balanced is, and has always been common mode noise rejection. Good cable construction will of course lead to consistency of noise on both cables ensuring common mode rejection.

Now w.r.t. studio balanced connections, i.e. AES compliant, that is not just about balanced, but a drive/load standard that is low enough impedance to dominate over cable parameters.

Sure. As you can see from its historic legacy, balanced lines were used to increase intelligibility. This is exactly why it made it possible to hang a pair of microphones above an orchestra, and have the tape machine 150 feet away, receiving that mic signal without degradation. Certainly noise rejection is one aspect, but so is the rejection of ground loops (that is why the balanced line system ignores ground).

No, that statement is quite true. A floating source is not the same as a differential source. It would only be truly differential if you center tapped it and connected the shield to the center tap, such that coupling to the cable shield is similar for both conductors. That is not the case for a cartridge.

This statement is a common myth, and being a myth, is false. A center tap degrades the Common Mode Rejection Ratio, on account of the simple fact that no center tap is really centered exactly. For this reason, center taps are never used. This is true of dynamic mics, cartridges, tape heads and any other inductive source including input and output line transformers. 
And than, we gonna “hear “the difference  between the 2: for me RCA is more open: good balance, beautiful placement , detailed and holographic. XLR: gives also a good balance, placement:okay, but the openness is less: “flatter” compared to RCA.  Conclusion: I only used RCA. ( my system: CEC cd-player, Auralic streamer, Metronome Technologie C6 (dac), Daniël Hertz M6L ( préamp) Wavac MD 805 m ( monoblocks) and Ilumnia Magister (speakers)
The problem here is that in order to obtain the benefit of balanced operation, your equipment must support the standard, AES48. Having introduced balanced line operation to high end audio, I can tell you that hardly any high end audio gear supports the standard and so you hear differences, and often degradation. That's a unfortunate because the technology clearly works (which is why all your recordings use it); you'd think audiophiles would be interested in something that prevents interconnect cables from interacting with their audio system. If you've ever heard differences between cables you know what I'm talking about. Imagine all the cables sounding as good as the best you've heard: that is the benefit.
I think I would be a great idea to ask the the great phono cartridge and phono amp designers to clear this up - hopefully they might all agree. Question: precisely how are cartridge and turntable wired to the phono amp to obtain fully balanced operation?
The first balanced line phono section was made by Atma-Sphere Music Systems in 1988 and offered in the first balanced line preamp in 1989. Since the cartridge is already a balanced source, its a matter of getting the signal to the preamp without involving that signal with the ground system (the tonearm tube and turntable). To this end, the plus and minus outputs of the cartridge are tied to pins 2 and 3 of the XLR connection. The tonearm ground then becomes the shield of the interconnect cable and ties to pin 1 of the XLR at the phono input. Since the phono input is balanced, it ignores ground and looks at what is different between pins 2 and 3. In other words, the signal is **received** in the differential domain. In the old days this was done with an input transformer with its primary winding simply tied to pins 2 and 3; the ground is simply the chassis of the preamp. Of course you don't need the transformer, but then you need a differential amplifier at the input of the phono circuit. This can be done with tubes or transistors. This is how our phono preamps work and the signal is kept in the differential domain throughout the preamp.


The tricky bit is that sometimes the tonearm manufacturer does not supply the arm with a removable interconnect cable. But most do, and usually if they don't (Rega comes to mind) it is possible to convert the arm anyway. Back in the old days, turntables like BSR, Dual, Garrard and so on had the tonearm wires exit the arm beneath the plinth where there was a terminal strip that had connections for the 4 cartridge wires plus the tonearm ground. That was where the interconnect cable was attached, so even for those ancient machines its fairly easy to install a balanced line simply by replacing the interconnect cable.

Thank you for all the effort in that input @atmasphere and the benefit of your wide knowledge and experience.  It throws much needed light.  I am finding this discussion very interesting as well as informative.

A.    If I understand correctly, to summarise, you say yes most cartridge arms can be wired fully balanced.  Balanced operation reduces noise, particularly in long wiring runs.


B.   "[balanced operation] prevents interconnect cables from interacting with their audio system...Imagine all the cables sounding as good as the best you've heard: that is the benefit."

Ooooh, I can see that one is going to be controversial.  You seem to be saying SQ differences between different cables arise from running single-ended, as most audiophile systems do, and not from the cables themselves.
Is it going too far to draw some further conclusions from that statement:
1.  All well-designed cables sound (much) the same in a balanced set-up.
2.  Money spent on expensive cables is (largely) wasted in a balanced set-up.  Therefore:
3.  There are SQ differences due to cables in a single-ended set-up so expenditure on cables can be justified.  But if you choose a balanced system, this will gain at least the same SQ improvements as buying expensive cables, but without the extra cost.  Pace - I accept in principle it is more costly to build balanced amplifiers than single-ended.


C.   "your equipment must support the standard, AES48; I can tell you that hardly any high end audio gear supports the standard "

Are you saying that some amplifier hardware fitted with XLRs and said by the manufacturer to be 'fully balanced', is not fully balanced and does not support AES48?  Presumably XLRs could be put on for show without the correct wiring behind?  If this is correct, someone suitably qualified should start naming names.
This statement is a common myth, and being a myth, is false. A center tap degrades the Common Mode Rejection Ratio, on account of the simple fact that no center tap is really centered exactly. For this reason, center taps are never used. This is true of dynamic mics, cartridges, tape heads and any other inductive source including input and output line transformers.

I never said that center tap would be better for noise rejection (though it absolutely could be). You appear to have have misinterpreted my use of center tap to imply a single ended ground reference, which is not the same as connecting the shield to a center tap to balance the signal w.r.t. the shield. That it is not used in audio (not needed) does not mean it does not work. It is used in other industries because it does.


https://www.pulseelectronics.com/wp-content/uploads/2016/12/G019.pdf

https://patents.google.com/patent/US20170131427A1/en

Certainly noise rejection is one aspect, but so is the rejection of ground loops (that is why the balanced line system ignores ground).

Grounds loops ARE common mode noise. Hence, the accuracy of my statement, to reduce common mode noise.


The problem here is that in order to obtain the benefit of balanced operation, your equipment must support the standard, AES48. Having introduced balanced line operation to high end audio, I can tell you that hardly any high end audio gear supports the standard and so you hear differences, and often degradation.

We are talking input to phono stages, i.e. cartridges, so not sure where you are going bringing this up. It is not applicable.


At this point we need to be pedantic since terms that are not interchangeable are being used that way, "balanced" refers specifically to the interconnect method, i.e. the signals are impedance balanced to the ground/shield, hence the noise on one is balanced and opposite to the other. That could be implemented with transformer coupling and shielded cable, or differential signalling and a shielded cable.
What is called a "balanced" input is balanced in the sense that it connects to a balanced interconnect, but electrically it is differential. The AES standard is a differential signalling standard coupled with a balanced interconnect.

Since the cartridge is already a balanced source, its a matter of getting the signal to the preamp without involving that signal with the ground system (the tonearm tube and turntable).


Which makes this statement as noted before inaccurate.  A cartridge is not a balanced source. It is a floating differential source.  If you twist the wires and maintain a consistent (w.r.t. each wire) shield to the amplifier then the interconnect would be balanced.

Because the cartridge is floating, and hence its output differential, going into single ended input, assuming you use the practices of balanced interconnection (with shielding), you can still have a low noise floor especially at low frequencies, because the common mode noise at those frequencies will be rejected. However, from a practical standpoint, this does not work well at high frequencies, due to parasitics. This is where the differential input comes in that will reject common mode not just at low frequencies but at high frequencies.

Unfortunately, too often balanced and differential are thrown around interchangeably and they are not and mean different things. This is confusing especially if you are trying for a deeper understanding.
See my previous two posts, clearthinker


The AES standard is balanced interconnect with differential signalling AND the source and load and cable impedance is defined. Really, at least to me, it is that defined impedance that justifies most of atmasphere's argument, with the balanced and differential taking care of the rest.

Defined and low impedance compared to consumer equipment impedance ensures that the relatively low capacitance and inductance of interconnect cables are essentially eliminated from the equation. Matching the cable impedance to the source/load impedance guarantee fast signal transmission with limited ringing and also makes resistance purely a level shift. By fast, we are talking so far beyond audio it is not worth even mentioning.

Balanced interconnection with differential signalling effectively eliminates noise, the only purported benefit of expensive cables.

Ooooh, I can see that one is going to be controversial. You seem to be saying SQ differences between different cables arise from running single-ended, as most audiophile systems do, and not from the cables themselves.
Is it going too far to draw some further conclusions from that statement:
1. All well-designed cables sound (much) the same in a balanced set-up.
2. Money spent on expensive cables is (largely) wasted in a balanced set-up. Therefore:
3. There are SQ differences due to cables in a single-ended set-up so expenditure on cables can be justified. But if you choose a balanced system, this will gain at least the same SQ improvements as buying expensive cables, but without the extra cost. Pace - I accept in principle it is more costly to build balanced amplifiers than single-ended.


C.  "your equipment must support the standard, AES48; I can tell you that hardly any high end audio gear supports the standard "

Are you saying that some amplifier hardware fitted with XLRs and said by the manufacturer to be 'fully balanced', is not fully balanced and does not support AES48? Presumably XLRs could be put on for show without the correct wiring behind? If this is correct, someone suitably qualified should start naming names.

I never said that center tap would be better for noise rejection (though it absolutely could be).
It would only be truly differential if you center tapped it and connected the shield to the center tap, such that
The parenthetical remark renders the first statement false. A center tap decreases noise rejection, at least at audio frequencies.

The second quote is certainly suspect. There is no attempt to make the connection differential, but to receive the signal properly differential techniques should be used if a high CMRR is to be expected.
Ooooh, I can see that one is going to be controversial. You seem to be saying SQ differences between different cables arise from running single-ended, as most audiophile systems do, and not from the cables themselves.
Is it going too far to draw some further conclusions from that statement:
1. All well-designed cables sound (much) the same in a balanced set-up.
2. Money spent on expensive cables is (largely) wasted in a balanced set-up. Therefore:
3. There are SQ differences due to cables in a single-ended set-up so expenditure on cables can be justified. But if you choose a balanced system, this will gain at least the same SQ improvements as buying expensive cables, but without the extra cost. Pace - I accept in principle it is more costly to build balanced amplifiers than single-ended.


C.  "your equipment must support the standard, AES48; I can tell you that hardly any high end audio gear supports the standard "

Are you saying that some amplifier hardware fitted with XLRs and said by the manufacturer to be 'fully balanced', is not fully balanced and does not support AES48? Presumably XLRs could be put on for show without the correct wiring behind? If this is correct, someone suitably qualified should start naming names.
Yes, cable manufacturers and inexplicably, many audiophiles, don't like to hear this stuff. But there is so much product out there that does not support the standard that there will be plenty of need for exotic balanced interconnect for a long time.


To be clear, I am saying that SQ differences between different cables are audible if there is no termination standard and if there are signal return currents present in the shield. So this can mean both single-ended and balanced, if the latter is improperly executed. Since that happens a lot in high end audio, we have a high end cable industry making expensive balanced line cables! Quite the opposite of how it should work.

Regarding your numbered points:
1), 2), 3) all Yes, if AES48 is observed.
C. Quite a lot of high end audio hardware has XLR connectors and are not balanced at all; the connectors are there for convenience only. Some VTLs and Lamm products are set up this way (examples I have had contact with did not have pin 3 connected to anything in the amplifier; this will introduce a buzz if the source driving that amp meets AES48 as the circuit is incomplete). Other high end audio products have XLR connectors and are fully balanced (such as ARC and mbl) but don't support the standard regardless. The mbl amp I had contact with was balanced because when it was monostrapped, you could then use the XLR input (meaning you needed two of these amps for stereo). This approach causes signal return currents to be present in the shield and results in a very low CMRR, making the connection susceptible to noise pickup and cable construction. The ARC stuff I've had contact with has had fairly high output impedances, preventing the preamp from driving anything less than about 30,000 ohms. The output was two single-ended stages that were driven out of phase with each other. This causes signal return currents to be present in the shield, and the relatively high impedance of the resulting system causes the setup to be sensitive to cable construction.

Thank you again atmasphere.

Given the haphazard wiring behind the XLRs and non-adherence to AES48 of many amps, I am indeed lucky (just that) to find my system is free from hum and other obvious non-matching artifacts and appears to have a very low noise floor - I hear nothing on no-signal until I turn the volume pot up a long way.

For reference, I (believe) I run fully balanced throughout.  Ortofon A90 on a Simon Yorke Aeroarm though a bespoke SY connection box into a van den Hul The Grail SB phono amp, Audio Research Ref 6, vintage Krell KRS200 monoblocks.

It seems wrong that getting the benefits of running fully balanced should be such an uncertain adventure.

And if nothing else, these exchanges have revealed the truth about the alleged benefits of high-end cabling.

It seems wrong that getting the benefits of running fully balanced should be such an uncertain adventure.
+1 Sure got that right. The point of the standard was/is plug and play.
"Quite a lot of high end audio hardware has XLR connectors and are not balanced at all; the connectors are there for convenience only."

What would be convenience in these cases?

I do have XLR-connected (for the lack of better understanding of what I really have) CD player to amplifier. All is quiet on that front, but now heaven knows if and to what level it is balanced and what standard, if any, it conforms to. It is really not what many would consider high-end to begin with so all odds are off.

In any case, interesting read, even somewhat understandable for dummies like me. Thank you guys.


Hi @glupson, given what atmasphere says about wiring behind the XLRs in many amps, perhaps rather than for convenience, the XLRs are there for show.

It seems to me that guys like John Atkinson should report on 'balanced' amps that are not actually wired balanced and/or do not conform with AES48 just like he reports on speakers that are 4dB less sensitive than the manufacturer's spec.  We want to ensure manufacturers are honest with their specs and that those who are not are exposed.
jaytor324 posts01-04-2021 11:26pmRCA connectors can't carry a balanced signal. You need to use cables with XLR connectors to support balanced. That's wrong. If you have a cable with a foil (conductor) shield you can convert and use the shield for the neutral.

I have Pass XA60.8 amps.  I have tried somewhat expensive SE cables and somewhat expensive XLR to my Allnic L-7000 pre-amp and to me the XLR carries more weight, clarity and enjoyment but I have gone thru several upgrades in gear and think I will try it again.  Allnics' top Pre-amp is SE an way above my price point.
I wonder if the benefits of SE vs XLR are system dependent.  Very well designed systems with well designed (AKA Expensive) gear is likely to be very quiet/low noise and allow the benefits of SE to shine.  In other systems like mine the benefits of noise control are more apparent/important and results in an overall impression of benefits.  As  Ivor Tiefenbrun fo Linn said;  "Garbage in, garbage out" and the noise on a lower level system is just being amplified.