Balanced vs RCA between amp/preamp

Rega Cursa 3 pre and  audio Research VT100 Mk III ( this model has rca input and I just do the test and if ok will move to Audio Research Ref 75se.)

 

@runwell 

Just curious what RCA pre and XLR power amp connected via ISO MAX transformer?

Just connect the ISO MAX transformer in between my RCA pre and XLR power amp,The sound is changed too. It is not very  active as it before and Sound volume is not gain +6db,but become a little small.  Totally different sound. I just remove it from connection. No good for thus isolation transformer.

 

So that's it. I will feedback when I receive and install the transformer in my system.

I tried the direct  RCA to xlr cable before, and I can hear the soundstage is not good.

 

 You suggest to use transformer isolation and you deny the way to use it. 

What is your opinion?

Audio Research reply directly that I should use transformer coupled  to connect RCA pre with their XLR only power amplifier.

@runwell If you are using a single-ended preamp, using a transformer might be the only way to drive certain power amps with a balanced input. ARC is often one of them. I'm not familiar with their current lineup, but it was only 5-6 years ago that some of their gear was only offered with a balanced input, but that input had a poor CMRR (Common Mode Rejection Ratio) according to a personal friend of mine who used to work there (Kalvin Dahl). Apparently it was only about 20dB. This meant that if you tried to drive it with a single-ended source, the distortion of the amp was very high and the output power was much lower. So a transformer was the only game in town if you had a single-ended preamp with that amp (which otherwise got good reviews).

If you have an ARC amp and a single-ended preamp, from what I've seen of their circuits I would advise the use of a transformer like the Jensen to do the conversion from single-ended to balanced, so I agree with ARC's advice above.

I don't like using transformers in the signal path which is why I designed a direct-coupled circuit that supports AES48. But transformers have their place; most of the classical LPs or CDs of recordings from the Golden Age of stereo (1958 to 1963) have several transformers in the recording signal path. Jensen and Lundahl arguably make some of the best transformers for this purpose.

Based on what you've told me so far, I would use the transformers! 

@atmasphere 

 You suggest to use transformer isolation and you deny the way to use it. 

What is your opinion?

Audio Research reply directly that I should use transformer coupled  to connect RCA pre with their XLR only power amplifier.

My Ayre electronics sound better using the differentially balanced outputs/inputs than the RCA's

" The problem with this approach" Do you mean Transformer coupled approach?

@runwell No. If you are dealing with a ground loop, the transformer can fix that, but take @ieales' post seriously.

The way to solve a ground loop is to purchase properly or fix improperly designed equipment. Adding a transformer is a bandaid. Bandaids fall off.

My company wired recording and film studios in Los Angeles and New York in the 1980s & 1990s. We had transformer and electronic balanced and unbalanced equipment to interface. Hundreds of connections that could be reconfigured into literally millions of combinations. Correctly done, there is no ground loop.

If you detail out your equipment and connections, perhaps we can solve your issue. By detail, I mean brand, connection, electrical power etc. Since we can now post images, draw a sketch.

@atmasphere 

" The problem with this approach" Do you mean Transformer coupled approach?

As far as I know transformer coupled way is to solve the ground loop.

That's the reason we use the transformer isolation instead of RCA to XLR cable,right?

 

So finally it goes down to the transformer isolation,it seems the usual way even the XLR output from the pre,they usually get the rca signal first and use the transformer to get the inverse signal and consist the XLR sigjnal. 

If the preamp has both RCA and XLR outputs its quite rare to see a transformer used for the XLR output.

In high end audio in particular, in a situation like this the RCA is one of the phases of the XLR output (which has an inverting and non-inverting output). The problem with this approach is that ground is being used to complete the circuit, and this leaves the circuit vulnerable to ground loops. One of the goals of the balanced line system is to eliminate ground loops.

In a balanced line system there is no need to lift the ground at one end of the cable. 

Try not doing it in a large multi-room facility like a sound stage, dubbing room. It may not be required with the AES-48, but until all gear is to that standard, prudence takes precedence over valor.

Most XLR gear is not transformer coupled. Not all is actually balanced.

In transformer gear, an unbalanced signal is fed through the transformer. The output can be XLR, banana, TRS, multipin, etc., etc.

While the Jensen transformers are excellent, they, like all transformers, still have a sonic signature.

Depending on the issue, adding transformers with the screen carried may not solve the problem.

@ atmasphere

        Thanks! I put the order a few days ago and will receive very soon.

So finally it goes down to the transformer isolation,it seems the usual way even the XLR output from the pre,they usually get the rca signal first and use the transformer to get the inverse signal and consist the XLR sigjnal. 

Am I right?

 

    I just want to have a solution between RCA pre and XLR power amp, it seems the transformer coupled is the simple way to go.

It is. A set of Jensen ISOMAX line transformers should do the job. They make one that has RCA inputs and XLR outs.

https://www.jensen-transformers.com/home-theater/audiophile/

They make them to order too- so you can get RCA in and XLR out although you don't see that on their site.

@ atmasphere

           Are you talking the connection between RCA preamplifier and XLR power amplifier ? or the circuit inside the amplifier?

          I just want to have a solution between RCA pre and XLR power amp, it seems the transformer coupled is the simple way to go.

 

@runwell Yes. We patented the use of a Circlotron output (which is direct-coupled and balanced) with a servo control to prevent DC Offsets from appearing at the output. The Circlotron is a push-pull circuit that allows for entirely symmetrical operation using a pair of tubes to drive the output. In our case we use 6SN7s for that task.

A Circlotron circuit employs floating B+ power supplies and so can have one side grounded or in the case of balanced output, both sides floating with equal impedance to ground, while at the same time not using the ground for anything to do with the signal. In this way it allows a direct-coupled tube output to support the balanced standard, AES48.

@atmasphere 

"  You don't need transformers, but without them supporting thebalanced starndard get a lot trickier. We devolopd a means that is direct-coupled and yet floats the same way that a transformer winding does"

     I want to know the detail of your means. Could you please explain. Thanks!

 

Why don’t i just plug all my gear into a very good balanced isolation power conditioner (with excellent CMR) and make my life easier fellas? A wise man once said, " Spend in the right places"

Though .....someone mentioned he gets aways with fewer gain stages. But, i doubt all manufacturers make the same design decisions.

Anyone have any idea if the Cello Palette (the later preamp version) is true balanced out? I have one coming into my possession and trying to decide if its worth the effort to have some Fischer to XLR cables made.

the sound of the interconnect won't be a thing

Malarkey!

Assuming balanced circuitry and connections are properly implemented, which far too often they are not, they can reduce common mode noise. FULL STOP.

For balanced interconnects to be immune to cable, they would have to be immune to the laws of physics. Balanced lines [and connectors] have impedance and impedance controls frequency response.

Regarding the full stop, internally in a true balanced circuit in addition to improving CMRR, you can also improve power supply immunity, and since CMRR can be high, you get insensitivity to ground noise.

Actually, the way the interconnects become "immune to cable" (sic) is through two mechanisms, all according to the laws of physics. The first is that the balanced system is low impedance- at 1000 ohms (or 600) the impedances are so low that the capacitance and inductance of the cable are swamped and become negligible- and thus inaudible. The second is that the signal is not sent as a ground return through the shield. If you violate either of these tenants, the cable becomes audible. This is easy to prove through both measurement and audition.

differential amps tend to be lower noise we don't need as much gain stages to get the job done

If number of stages is a criteria, use a transformer. Differential amps per se are all over the map in terms of gain vs noise. The devil is in the details.

Transformers limit bandwidth and make distortion. Without them the circuit is noticeably more transparent. We've been doing balanced line longer than anyone else in high end audio; don't think we haven't tried transformers, and of course we are known for being transformerless :)

the other reason for balanced lines is elimination of ground loop noise

I'll wager that 6 9's of 'balanced' home audiophile systems do not lift the shield at the destination. Depending on amplifier design, there may be ZERO ground loop improvement over an unbalanced system.

In a balanced line system there is no need to lift the ground at one end of the cable. You are correct about the amplifier design issue; IME/IMO many high end manufacturers don't understand grounding and don't understand how balanced lines work either.

The balanced line system was created to get rid of interconnect cable colorations

The balanced line system was invented by the telephone company to increase noise immunity and power transfer over long distances. Nominally 600Ω, but at 1 frequency ONLY! Low frequency performance is abysmal.The 'telephone sound' is a direct result of balanced cables.

:)  of course noise isn't a cable artifact, but you forgot to mention the loss of high frequencies, which made transcontinental phone calls impossible prior to balanced lines. If loss of highs is not a coloration, what is??  Yes, the phone company did just that, and the idea was quickly adapted by the recording industry as running microphone signals over a long distances was a similar problem. Through the ability to transfer power the system swamps cable capacitance and inductance (both of which cause interconnect cable coloration). This is the low impedance aspect to which I referred earlier. Our balanced preamps feature miniature power amps as their line sections- they can make a little power.

Many balanced devices are bodged to accommodate unbalanced operation and coupled with generally incorrect balanced wiring, they don't stand a snowballs chance of optimum operation in unbalanced mode.

If 4+ decades in electronics has taught me anything, it's that if it can be screwed up it will be:

• inexperienced engineers
• incompetent sales staff
• ignorant consumers

This has been a beef of mine for decades, but just because this is so does not mean that all balanced line products have these issues.

I should have said "Use caution if driving an unbalanced amplifier from the balanced outputs."

We run into that problem too. What most people don't understand is that balanced and single-ended operation is inherently incompatible; you can't have 'quasi balanced' or any such nonsense. Either its balanced, or in the case above, unbalanced. In our preamps, since the output floats with respect to ground (no signal return current in the ground) if you attempt to use only one of the signal pins (ex.: pin 2) and ground (pin 1) you will get a buzz. This is because pin 1 has no direct connection to the return circuit of pin 2 and so pin 2 acts like an antenna. To correct this, pin 3 in this situation has to be also tied to ground (and because our output floats, this can be done without damage) to prevent the buzz. But of course then the output of the preamp is single ended, no longer balanced.

Tidbit about XLR cables and plugs.

In the late 70's I worked as a salesman at Shrader Sound in the Georgetown neighborhood in NW DC.

Bill Shrader was long out-of-the-picture, and the silent partner who kept the business afloat was Jim Canon, who developed the "Cannon connector", used at the time on lots of professional microphones.  When Jim sold out to United Technologies, they made a "Cannon connector" with a plastic insulator ("XLP") and one with a rubber insulator ("XLR").

Hi Al,

I should have said "Use caution if driving an unbalanced amplifier from the balanced outputs."

Thanks for catching.

- Best,
    Ian

I had a low level buzzing in RCA when i went to balanced it went away plus the system got quieter and more dynamic.

Use caution if driving an unbalanced amplifier. Best results will probably result from using Pin 3 & Gnd ONLY.

Hi Ian,

Not sure where you are quoting this from, or if you are quoting it, but to be clear I assume this statement is intended to apply to the unusual situation in which XLR cables are used to connect the balanced outputs of a preamp to an amp which receives the signals provided to its XLR inputs in a single-ended manner, and would short one of those signals to ground if the signals on pins 2 and 3 were both routed to the amp by the cable. In most cases, of course, at least when it comes to consumer-oriented gear, unbalanced amplifier inputs would be driven by the preamp’s unbalanced outputs via RCA cables, and the statement would not apply.

And in most cases involving consumer-oriented amplifiers which provide XLR inputs but are not "fully balanced" I would nevertheless expect signals provided to their XLR inputs to be received differentially, not single-ended. As is the case with the OP’s amp.

In any event, thanks for providing the additional insight in your post.

Regards,
-- Al

for anyone interested, HDAM module schematics are available here https://muzgdiy.files.wordpress.com/2015/05/all_versions_2.png

These HDAM's consists of discrete surface mount components with short mirror image L/R signal paths.

IMO, this is marketing malarkey. It is not possible to 'mirror image' active circuitry as devices have functions on specific pins. Marantz literature always shows a pair of identical HDAM modules and never a mirrored L/R pair which, if they existed, would be featured front and center. Additionally the Service Manual has only one HDAM-SA3 schematic for a bipolar amplifier circuit.

Discrete circuity 'suffers' from increased parasitic L & C, component tolerance and reduced supply immunity, all of which contribute to the 'sound'. Some opine that discrete circuitry takes the edge off the literally 1000's of integrated circuits through which the signal passed before the final storage medium.

Somewhat troubling is the -ve phase is derived from the post Wolfson WM8816 volume control unbalanced +ve output through an additional 2 HDAM and 2 gain stages. These then feed a pair of balanced tone control circuits. Strange.

Use caution if driving an unbalanced amplifier. Best results will probably result from using Pin 3 & Gnd ONLY.

A largely ignored electronics property is power supply linearity. The impedance and phase linearity of the ubiquitous LM3x7 / 7xM  et al. regulators vary drastically between manufacturers and implementation. Some are positively abysmal suffering 180° phase and a couple of orders of magnitude Z change in a few Hz.

Marantz makes a fair bit of 'noise' about their power supply design and examination of the schematic shows that the audio supply is discrete and well designed.

A negative in the pre-amp [and any versatile control center] is the large number of relays in the circuitry. ALL switching is audible and cumulative.

Bottom line, if you like the sound, don't worry about the innards.

PS I have a Marantz CD-6006. I like the sound & features. I don't worry about the innards.

I like my balanced connects, no loose or cold welded RCA plugs, always an easy and solid connection.  Using “Worlds Best Cables” with  2534 wire that cost $30 a set.  Couldn’t be happier, but my equipment is fully balanced differential from the dac to amp.   

As promised, I have downloaded and examined schematics for the OP’s preamp and amp, which as I had mentioned in my previous post can be obtained at hifiengine.com if one is registered there.

The amp is not fully balanced. However, while the circuit configurations used to receive balanced and unbalanced inputs are of course somewhat different, both inputs are processed through circuitry described as follows:

HDAM SA3

Marantz developed its own discrete circuit boards to replace standard IC's. These HDAM's consists of discrete surface mount components with short mirror image L/R signal paths. Those devices are doing exactly the same thing as the Op-Amps, but outperform the regular IC Op-amps dramatically in terms of the Slew Rate and reduced noise level, resulting in a much more dynamic, accurate and detailed sound. Over the years Marantz developed different types of the HDAM to improve quality and to fit to the special requirements of a product category like CD or amplifier.

Two HDAM SA3's are in the path through which each balanced input is processed; one of those two is in the path through which each unbalanced input is processed.

The preamp is also not fully balanced. However, a good deal of the circuitry which precedes its balanced outputs is symmetrical and is therefore balanced, although not differentially (i.e., it does not utilize differential stages). That circuitry also utilizes the HDAM SA3, followed by a number of stages utilizing discrete transistors.

Given all of that, my guess in this specific case is that it is more likely than not that a balanced interconnection will be preferable to an unbalanced one.

Luisma31 8-4-2019

Reading the initial post again I missed something, the input source is single ended, this is a question for the others answering in this thread as I'm not sure of the answer. When the source is single ended shouldn't be the output single ended as well even when using the XLR output?

While I suppose there may be a few exceptions, usually a preamp which provides balanced outputs when it is provided with balanced inputs will also provide balanced outputs when it is provided with unbalanced inputs. And examination of the schematic for the OP’s preamp confirms that is the case here.

Best regards,

--Al

 

Reading the initial post again I missed something, the input source is single ended, this is a question for the others answering in this thread as I'm not sure of the answer. When the source is single ended shouldn't be the output single ended as well even when using the XLR output? 

I own balanced equipment, before I had SS unbalanced amps, on my rig and judging with my ears and a professional pianist ears as well I have replaced the balanced cables with mogami 2534 shielded, mogami 2549 unshielded, wireworld eclipse and in all three instances we weren't able to notice any difference in sound. Additionally to all these, replacing other components like dac, USB cables etc. Haven't made too much of a difference, as a matter of fact there have been a small difference in instrument presentation and Soundstage when changing things at the source but almost not noticeable not like others report on similar rigs with unbalanced connextions. Some people have recommended not using balanced shielded cables as they state sounds worse, I don't doubt it I just can't tell the difference on my rig.

My point is I truly suspect by empirical experience that balanced well designed equipment could be impervious, or maybe I should say apparently more resistant to changes on interconnects. 

Just my thoughts, 

Oh one more thing, there is unbalanced only equipment that price wise I seen it to be more expensive that their balanced counterpart, it might not be a general rule but it happens so cost IME is not so much of an issue. 

So back at wec56, yes using balanced vs unbalance there could be a difference IMO. You should experience more of a difference using different equipment manufacturers than cables anyways. 

Enjoy your system 

Thanks for your input, Peter (Pbnaudio). Yes, depending on the specific designs what could be connected first and disconnected last when XLR cables are connected and disconnected may be either chassis ground or circuit ground. As you are doing in your designs and as explained in this Rane application note, connection of pin 1 to chassis ground in both components is proper practice (although unfortunately far from universal practice), with connection of chassis to the shell being optional.

On another note, regarding whether or not the OP’s specific components are fully balanced and whether or not they use inexpensive op amps to generate or receive one or both signals in the balanced signal pairs, I see that service manuals for these components, presumably including schematics, can be downloaded at hifiengine.com if one is registered there. I’ll try to take a look at them tomorrow, as that site imposes a limit of three downloads per day and I’ve already reached that limit today.

Best regards,
-- Al

Regarding ground connection being connected first and disconnected last  IS true if one wire the balanced connections as perhaps intended. The shell which has the 4th terminal on a 3 prong XLR connector is intended for Chassis ground.  XLR connectors are available with up to 6 (7) termination points.  

Most however don't use this 4th connection point, including me.  Pin 1 Chassis Ground, Pin2 Positive Node Pin3 Negative node.  So to refer to the OP since your Marantz gear have the same termination on both pre and power amp - your in electrical phase and don't need to do anything else.

As far as balanced operation which in my opinion offer vastly improved performance dynamics for an example and noise rejection and that the interactions of the cable is practically eliminated the list goes on.  All the equipment we make is fully balanced form input to output. Even on our economy line Liberty Audio the gear is fully balanced.

Good Listening

Peter

https://pbnaudio.com

Sorry, but posts like the above are just fanboy prattle, equivalent to
      "I changed everything and it sounded different."

Many balanced devices are bodged to accommodate unbalanced operation and coupled with generally incorrect balanced wiring, they don't stand a snowballs chance of optimum operation in unbalanced mode.

If 4+ decades in electronics has taught me anything, it's that if it can be screwed up it will be: 

• inexperienced engineers
• incompetent sales staff
• ignorant consumers
  

My home system was dramatically improved by 2 instances of changing to XLR cables: the tube preamp (ARC) to SS amp (McIntosh) connection eliminated noise that was present with unbalanced cables (cables were about 7 feet long) & my Marantz SACD (SA-11S3) to the pre made a huge difference, whether only because the balanced connection was louder (as some attest) or the cable was of far better quality than the previous unbalanced one, I don't know.

audiorusty

Im envious. I always lusted for A-S kit, but was always out of my budget. Perhaps the closest I got was when I had Accoustats with their OTL amps. Did a few modes to the boards + chips and cryoed NOS tubes. Even if the sound was comparable, the Accoustats were affixed directly behind each speaker, designed exclusively for their panels.

Must be cool just to look at them, such a classic design honoring an important era in communications kit that looked like military hardware 

A note about balanced pro audio...In my long career as a concert soundman, I can attest to the fact that NOBODY unplugs a balanced anything while the system is powered up, and if somebody does I will possibly throw them out of the building. The balanced connections DO NOT stop noise when unplugging live connections.

The single biggest improvement I ever made to my system was when I switched from RCA cables to XLR balanced but I am not using Marantz gear I am using Atma-Sphere so YMMV.

the sound of the interconnect won't be a thing

Malarkey!

Assuming balanced circuitry and connections are properly implemented, which far too often they are not, they can reduce common mode noise. FULL STOP.

For balanced interconnects to be immune to cable, they would have to be immune to the laws of physics. Balanced lines [and connectors] have impedance and impedance controls frequency response.

differential amps tend to be lower noise we don't need as much gain stages to get the job done

If number of stages is a criteria, use a transformer. Differential amps per se are all over the map in terms of gain vs noise. The devil is in the details.

the other reason for balanced lines is elimination of ground loop noise

I'll wager that 6 9's of 'balanced' home audiophile systems do not lift the shield at the destination. Depending on amplifier design, there may be ZERO ground loop improvement over an unbalanced system.

The balanced line system was created to get rid of interconnect cable colorations

The balanced line system was invented by the telephone company to increase noise immunity and power transfer over long distances. Nominally 600Ω, but at 1 frequency ONLY! Low frequency performance is abysmal.The 'telephone sound' is a direct result of balanced cables.

that being said your Amplifier and preamp need to have transformers for the input,outputs to be what is considered a True balanced .

This statement is false. You don’t need transformers, but without them supporting the balanced standard gets a lot trickier. We developed a means that is direct-coupled and yet floats the same way that a transformer winding does.

Many owners of Atmasphere gear (amps to preamps....all balanced) have reported the same cable differences that others have reported on other balanced gear.

Oddly, they’ve not been reporting them to me.

A balanced signal is simply two unbalanced signals, one 180 degrees out of phase (mirror image).

This statement is incorrect. With a proper balanced signal, the non-inverted phase is created with respect to the inverted phase, **not ground** (which is for shielding only). So its not two unbalanced signals- its only one, which floats with respect to ground (IOW, if you wanted, you could run a balanced signal with only two wires by simply omitting the shield)! This fact is poorly understood, but think of a line transformer- it does not use a center tap- one side of the output winding is tied to pin 2 of the XLR, the other side to pin 3. No ground connection at all. **Balanced lines if properly executed ignore ground**.


So it isn’t two single-ended signals- although a lot of manufacturers think it is, and in so doing degrade the performance of the balanced connection (and allow for interconnect cable artifacts and ground loops to creep into the system sound equation). When we built the world’s first balanced line preamps back in 1989, it didn’t occur to us that we could do that without supporting the standard. I was a bit shocked when I started to see other balanced gear that in no way supported the standard, and then exotic interconnects appeared because they were needed to work with such substandard equipment. You’d think that audiophiles would jump at the chance to no longer have to spend big $$$$ on cables and yet still get the best results...


In a nutshell, here is the standard:
1) pin 1 ground, pins 2 and 3 are signal. Pin 2 in the US is non-inverted side of the signal
2) ground is ignored, the signal floats; the pin2 signal is created with respect to pin 3 and vice versa
3) the system is low impedance- if there is an output XLR, its able to drive 1000 to 2000 ohms with ease (the old standard was 600 ohms and our preamps support that)
4) the signal travels in an interconnect consisting of a twisted pair with an independent shield.

I clearly said that the pin lengths on the male connectors of my XLR cables appear to be the same for all of the pins. It is the female connector for which I described a difference, which when mated with a male connector having equal length pins would result in the ground connection being made first, upon insertion, and removed last, upon removal.

Al, for all these decades of doing balanced connections, I’d never noticed that. You have to look quite closely at the female connector!! @millercarbon, my apologies on this point.

https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces?_pos=1&_sid=87340c17d&_ss=r

A lot of informative info before this summary in the link above.

SUMMARY

Professional-grade balanced analog audio interfaces can provide a 12 to 16 dB SNR advantage over unbalanced interfaces due to the high +24 dBu signal levels used on balanced interfaces. Consumer-grade balanced interfaces can only provide 3 to 6 dB SNR advantage due to the relatively low +14 dBu (4 Vrms) signal levels.

In addition, the differential amplifier or transformer in a balanced input can provide an incredible 50 to 100 dB rejection of ground-loop interference. This is usually sufficient to reduce ground-loop interference to completely inaudible levels.

In an unbalanced interface, the shared use of the shield places ground-loop currents in the audio path. Unbalanced interfaces are very sensitive to ground currents flowing between audio components. This is not a problem with balanced interfaces due to the use of dedicated audio conductors.

Copper braid and foil layers provide shielding against RF interference. In a balanced cable, the shield does not carry the audio signal. The audio conductors are fully surrounded by the shield but are electrically isolated from the shield. In an unbalanced system, the RF shield also serves as the audio ground. This dual use of the RF shield, in an unbalanced system, causes a slight increase in susceptibility to RF interference.

Copper braid and foil shields do not provide any protection against magnetic interference. Magnetic fields easily pass through copper and foil. If star-quad cables are used in a balanced system, magnetic interference can be rejected by the CMRR of the balanced input receiver. In a balanced system, 4-conductor star-quad cables can reduce magnetic interference by 20 to 50 dB when compared to standard two-conductor balanced cables.

These numbers should be hard to ignore, but the hi-fi industry has been slow to change. Many high-end audio products still are not equipped with balanced interfaces. Others have consumer-grade 4 Vrms balanced interfaces. These are a partial step in the right direction.

The facts show that it is virtually impossible to achieve state-of-the-art audio performance using unbalanced interfaces. We see this in the lab when we measure balanced and unbalanced interfaces under ideal well-controlled conditions. Outside, in the real world, the advantages of balanced interfaces are larger than a set of balanced vs. unbalanced specifications would indicate on a product data sheet. The differences can be extremely large when ground loops, RF interference, and magnetic interference are encountered in a typical audio system.

Our recommendation? Avoid unbalanced (RCA) analog interfaces whenever possible! Look for professional-grade balanced interfaces when buying audio products. Look for CMRR specifications on balanced inputs. Consider replacing audio devices that do not support balanced interconnects. These unbalanced-only devices are probably a weak link in your audio chain.

Engineears 8-2-2019

Horse puckey! I just got up, walked over to my handmade true-balanced end-to-end differential headphone amp, disconnected my Mogami XLR interconnect from my R-2r resistor ladder DAC and measured the pins on its standard Neutrik-branded male connector. ShOcKeR! All pins are the same length.

So I thought, well there’s *no*way* anyone would mansplain so authoritatively if they weren’t actually knowledgeable. Better give them the benefit of the doubt and find another cable with a non-Neutrik XLR connector on it. It took some digging, but I eventually found another cable with Amphenol XLR connectors. Nope. All the same length....

... Today, unless you can link to a whitepaper or standards doc that specifies a longer ground pin, I say we can safely assume the pins are the same length.

@engineears

Apparently you didn’t read my post on this subject very carefully. I clearly said that the pin lengths on the male connectors of my XLR cables appear to be the same for all of the pins. It is the female connector for which I described a difference, which when mated with a male connector having equal length pins would result in the ground connection being made first, upon insertion, and removed last, upon removal.

Regards,
-- Al

Also prefer balanced cause I’m not a fan of single ended cables use of the ground screen to carry 1/2 of the signal. I theorize that this is why there is so much more variation in sound from one type of cable to another vs balanced xlr where the shield is separate from signal carrying conductors

I began my transition from rca to diff balanced kit 2 decades ago.

Same nonsense appears here as back  then (that they are ONLY for long runs) I have heard differences between 0.5m and 1.0m XLRs

Dif balanced is basically 2 totally independent channels (hense doubling the cost), though they often incorporate the same output transformers. 

EVSs new EVS 1200 has 2 separate channels in it whereas most of the similar class D stereo amps do not. Appreciating his knowledge, I bought one

Buyer Beware:  I used to call out the hi end mag editors for giving dif balanced kit to 'reviewers' whose systems are NOT dif balanced. I finally gave up. 

A lot of kit has XLR I/Os but the kit itself is NOT dif balanced, therefore the listener will not hear the difference

RicEVS, wrenth,  and engineears have it correct

This is simple. If both devices was designed for full balanced support then it is clear that XLR is preferable solution. If one of the device is single ended then RCA is perfectly normal.
I tested many cables and devices. This rule is in general pretty common. I I join my MC1.25 monoblocks with C2600 preamp with XLR and C2600 with Chord Dave with RCA since Dave construction is SE.
Simple as that.
Yea, sure. Different cables, hybrid devices, balanced architecture implementation can effect the sound eventually but the rule more or less remain.
One of the earliest posts was that XLR is for long distance connections. True, but super HIEND equipment will benefit from it as well. If I adjust the position of my speakers by half of inches and I hear it then why extra clarity provided by XLR should not have the same influence.
Over 20thy years of adventure with audio teach me that there are no boundaries in this hobby.

Horse puckey! I just got up, walked over to my handmade true-balanced end-to-end differential headphone amp, disconnected my Mogami XLR interconnect from my R-2r resistor ladder DAC and measured the pins on its standard Neutrik-branded male connector. ShOcKeR! All pins are the same length.

So I thought, well there’s *no*way* anyone would mansplain so authoritatively if they weren’t actually knowledgeable. Better give them the benefit of the doubt and find another cable with a non-Neutrik XLR connector on it. It took some digging, but I eventually found another cable with Amphenol XLR connectors. Nope. All the same length.

I’m going to trust Nelson Pass, Atmo-Sphere, and the electrical engineering professors who mathematically demonstrate how differential amplification (internally balanced components) are inherently better performing but also more difficult to engineer. Not a lot more difficult, but clearly complex enough to confuse your average solder jockey or audiophile store salesman.

Now, maybe some old Korean War era PA system cables used an early version of the standard with a longer pin, but they did a lot of things differently 60-70 years ago. Today, unless you can link to a whitepaper or standards doc that specifies a longer ground pin, I say we can safely assume the pins are the same length.

PS: When people say balanced is not inherently better, they mean that having a balanced circuit in a badly designed amplifier isn’t going to make that amp sound better than a really superbly engineered unbalanced amp. It doesn’t overcome an otherwise poor design.

Millercarbon hit the nail on the head

Many owners of Atmasphere gear (amps to preamps....all balanced) have reported the same cable differences that others have reported on other balanced gear.  I wish it were true that running balanced let you use Mogami cables and nothing sounds better.....just is not true.

Similar but different topic - I didn't want to start a thread.
I want to take my DAC RCA outputs and feed two amps (want to bi-amp my speakers).  I'm looking for a y cable that will put out the same signal rather than a left right stereo split.  

Q2: Is this a bad idea?  DAC is Qutest and has no volume control.  That is on the amps.  

If you have true balance from out put to input XLR is the way to go