XLR or single ended cables and why?


Few audio equipments reviewers swear by their reputation if there is any that XLR connections improve quality of the sound sonically. Some stated there is none. Can someone scientifically help me to make a wise decision to choose between XLR and singled-ended cables?
andrewdoan
In my mind, I think of it this way. First: Do you need to deal with very long runs (say greater than 30 feet, and yes, I did just pull that number out of the air ;) between source and pre or between pre and amp? If so, stick with XLR. If not, go with whatever is attached to the equipment you think sounds the best. The only place XLR will hurt is your wallet when you factor in the premium most makers charge for having it and the only place it will help is on extremely long runs. Make your decision based on what equipment sounds best to you, not on what type of interconnect it uses. Hope that helps!

I would reccomend a quick forum search on this subject.

I have read some fabulous threads here on this subject, which included the participation of the designers of some of Audiogon's most well respected gear!

Since in your post you do not state whether your gear is balanced by design, there is no simple answer.

Originally almost exclusively reserved for pro-audio use, balanced components are designed to operate in unpredictable professional working environments They offer maximal S/N (signal to noise ratios), and standardized connectivity. Today's well-designed balanced high-end equipment, when connected with balanced IC's, offers the benefits of lower noise floor and better radio frequency (RF) rejection.

On the other hand, well-designed unbalanced equipment offers sonic (and sometimes lower price) benefits which make simpler circuit topologies popular. These designs can, however, be more prone to RF noise, which has become (with Cell phone, microwave, computer, and WiFi) an increasing feature of the home environment.

Hope this helps,

If you don't find your answers by reading previous threads, please let us know more about the boxes you are connecting up.

For the music,
Depends if the components are designed as truely balanced or not. For instance, don't by BAT gear and run it single ended. Your not getting the sound you paid for.
Sorry, It's the Krell 40oXi and the companion SACD Standard. Both has balanced connnections. I have numerous singled-ended RCAs from Kimber, H.T,Audioquest...Cablings are expensive nowadays and I am just abt going broke for my hobby.
I have run 20' MIT 350 EVO, 30' Kubala-Sosna Emotion and 30' Purist Dominus RCA cables, and 25' MIT 350 Ref and 30' NBS Statement XLR cables, and there was only one issue of noise - surprisingly the NBS Statement XLR 30' cable. This cable had a low-level hum which was only resolved when it was re-terminated to less than 20'. I suspect this had more to do with the NBS's weave design than anything else.

There was never an issue of radio-station pickup, interference or other problems due to appliances, AC units, sump pumps, etc., turning on or off in the environment, with these longer cables. The 30' RCA Dominus is an awesome cable with no problems whatsoever. There are a lot of posts on A'gon that claim you need to go balanced cabling for such long runs but my experience runs counter to this. It's all in the cable design, not its length.

Concerning what audio reviewers swear by, well, who cares! Why not try this out for yourself? The only way to know for sure which cable termination works well for any given component is to try the exact brand/model of a cable in both RCA and XLR termination. Once you change either the brand or model, the only valid test is to get that same brand/model in the other termination and listen again.

I have made several cable comparisons with many truly balanced ARC, BAT and Aesthetix electronics and with some others that have XLR connectors but which were not truly balanced designs. Each and every time, the XLR cable always outperformed the same RCA cable with truly balanced products. The most dramatic difference was the Aesthetix Io phono stage. There was a huge improvement in the protrayal of space and decays with the XLR cable. Even when I tried lower performance NBS XLR cables, these easily outperformed the much higher priced/performance Kubala-Sosna or Purist Dominus RCA cables here. But when I was able to try the K-S XLR cable, it was absolutely breathtaking. The comparison between the K-S Emotion RCA vs. XLR was quite an awakening for me with the Io. The Io simply needs to be run from its balanced outputs to do its magic.

I then did the exact same experiment with the Manley Ref DAC. This has XLR connectors but is not a truly balanced product as it uses transformers to generate the complimentary output. Here, there was barely a difference between the two terminations of the K-S Emotion cable. And this difference was most likely due to the Aesthetix Callisto line stage operating "better" with a balanced input. But unlike the case of the Io experiment, I could drop in a Dominus or K-S RCA and either of these would destroy the NBS XLR. The Manley clearly did not require the use of XLR cables to perform to a high level as did the Io. Here, the sonic strengths of the K-S and Purist shined through independent of the cable termination.

If you find an XLR cable that works well for you, it may not cost any more than the RCA equivalent. Some companies charge a little more and some do not. You have to try this all out for yourself and put your audio magazines back on the book case.

John
Salestalk and Ads are designed to make you fearful. Fear that you are somehow not getting the most out of your high $$$ system. And fear propels consumers to get their wallet out and spend more $$$

Do not be concerned: Wire is wire. There is no big deal to XLR.

Plug whichever existing interconnect cable you like best into your system. If you have an excessive hum, hiss or noise problem then by all means try something different...maybe even XLR. But don't expect any sonic miracles...a lower noise floor is the most you should expect to gain.

A cable is simply a connection (XLR or RCA, copper, silver or gold) and at audio frequencies you usually don't have to worry about shielding in most domestic environments. An unbalanced circuit can sound just as good as a balanced one in the majority of applications.

I would only ever worry about this if you already have a problem. If you do have a problem then consuider that it might be a component failure/compatibilty problem rather than assume a bad RCA cable.
In my limited experience, I tend to agree with balanced cables for balanced electronics. Krell states that both components you have are balanced. Nothing to get excited or impatient about. Mortgage or rent, food, beer, and some good CD's come first.
Shadorne - If implemented properly a balanced component uses differential circuitry throughout - each phase (+ and -) of the signal has its own signal path. There are pros and cons to this, but it is far more than just another connector type.

There are lots of other threads that explain this in gory detail.
Balanced audio interconnects (XLR) utilize two conductors, while standard RCA audio interconnects use only a single "unbalanced" conductor. This enhanced design gives balanced audio interconnects the power to provide greater resistance against sources of noise (RF, EMI, etc.). The result is a more pure signal transfer, especially in longer-run applications.

You may or may not hear a difference between XLR and RCA in short runs, however XLR should prove quieter on very long runs or in set-ups where many cords come in contact with each other...think rock concerts, where all instrument and mic cords are XLR.
Ghostrider45,

You are right that I have oversimplified.

RCA uses ground to carry half of the signal whilst XLR uses an additional wire. Signal levels are different as well. Circuits are designed differently too. Using the chassis for carrying part of the signal (RCA) does run an increased risk of picking up noise. A larger signal (balanced) with shielded cables (XLR) will be relatively more immune to noise.

But all this is really splitting hairs when considering most domestic applications. Many consumer grade equipment manufacturers offer only RCA connections and for good reasons; the majority find these circuit designs/connections perfectly acceptable.
Tvad sez:
however XLR should prove quieter on very long runs or in set-ups where many cords come in contact with each other.
Exactly. Plus the common mode rejection (i.e. "noise" that is common to both sides of the channel is cancelled out). Often it is twice as loud (spl) at the same volume control setting.
Shadorne, Is it a big deal to have an extra increase of 6db with XLR ? That's a lot of extra juice. Running either at 4 or 8 ohm, It requires double in wattage power for each 3db increase. Isn't it ? BTW, I have my MD. pulled the wool out of my ears the other day. Thanks for the advise.
Simple answer: With your Krell gear, you should definitely try out a balanced connection (and this is regardless of how long your cable run is). You don't need to commit first to purchasing the XLR interconnects if you can borrow a pair from a friend or a store demo for audition. Of course it would be ideal if you could either get ahold of a pair that corresponds to your usual reference single-ended IC's, or else wrangle pairs of the same audition model in both XLR and RCA versions so that the comparison isn't confounded by uncontrolled variables. Then just listen, not for noise per se, but for probably somewhat subtle (which is not to say unimportant) musical differences, especially concerning transient, dynamic, spatial, tone color saturation, and transparency/resolution qualities. Remember that because a balanced connection will usually yield a higher volume than single-ended (typically about 6dB hotter), for valid results always compensate with the volume control to equalize levels when performing A/B comparisons.
Technical reasons only - don't read this if you have a headache...

You have to consider the signal transfer through the cables and also the quality of the circuits on both ends.
Balanced circuits are more complicated, so more things can "go wrong" with them. If you go by the motto "the simpler - the better" then you'd probably prefer single-ended circuitry. There is a reason why SET amps are popular...

Now for the cables themselves. On a technical basis, cables have two signal wires in opposite phase. Logically, it is best to arrange these two wires in a balanced geometry (even for RCA cables) **AND** equalize the magnitude of the currents flowing in them. The electromagnetic fields of the two wires will cancel each other, so you get the least leakage (i.e. noise) from this cable. In addition, the geometrical balance will reject externally-induced noise.
Balanced circuits almost always guaranty the above condition for the equal magnitude of currents. Single-ended circuits do not always adhere to that. The reason is that the single-ended stereo (or multi-channel) circuits usually **SHARE** a common ground. The currents generated by the Left channel driver **CAN** flow in any ground wire in any interconnect, since they are all shared electrically, and have roughly the same resistance.
It is a different situation if the grounds are electrically seperated. Such is the case with a true dual-mono implementations or monoblock amplifiers, if they don't share grounds with an external ground wire or through the AC ground.
Confusing? Perhaps a little bit...
Bototm line is, that for your interconnect to do a good job - you either go balanced (guaranteed "success") or pay special attention to your single-ended setup. Anything else will compromise the symmetry of current flow in your interconnect and would make them possibly the "weakest link"in your system.
Tvad wrote:

"standard rca audio interconnects use only a single "unbalanced" conductor.

This is not true. Single ended RCA terminated cables use two conductors. One positive, the other negative. The (+) carries the signal away from the source. The (-) carries the signal back towards the source. Both conductors have an equal effect on sound quality. For this reason, one should never use audio rca cables in which the (-)conductor is a braided shield.

A balanced XLR cable also carries two signals. One being in-phase, the other out of phase. A third ground wire allows the ground potential between the components to "equalize".
" For this reason, one should never use the one with(-) as braid shield."

Tvad, would you please explain a bit more. Most of my ICs have one (+) connected to the pin the other (-) connected to the outer side of the ring on top of it is the barrells. Except for Kimber ICs where they use up to three conductors.
Reb1208 and Andrewdoan, my statement was copied directly from the Cobalt Cable website. Any errors are due to the info published by Blue Jeans Cable...
Tvad:
my statement was copied directly from the Cobalt Cable website. Any errors are due to the info published by Blue Jeans Cable...
It's sad that it was written in the first place and even more so that it makes the average person believe such nonsense - and quote it!
Not your fault, but it's not a good thing...
If nothing else, it convinces me that not all cable manufacturers...or perhaps just the marketing departments...know what the hell they are talking about. I'll certainly cross Cobalt Cable off my list of potential suppliers.
It is a different situation if the grounds are electrically seperated. Such is the case with a true dual-mono implementations or monoblock amplifiers, if they don't share grounds with an external ground wire or through the AC ground

In the case of mono amps with single ended inputs they will share the same circuit ground, they are connected together at the single ended source, ie. pre-amp.

steve
Shadorne, Is it a big deal to have an extra increase of 6db with XLR ? That's a lot of extra juice. Running either at 4 or 8 ohm, It requires double in wattage power for each 3db increase. Isn't it ? BTW, I have my MD. pulled the wool out of my ears the other day. Thanks for the advise.

Andrewdoan,

No there is very little current and almost no power flowing through interconnects...input impedances of devices they connect to are normally pretty high.

All a high signal level means is that if there is noise being picked up or if there is noise in the preceeding circuit then the Signal to Noise might be less by about 6db or so compared to RCA (which has a lower signal level). This is in "Theory", however, in practice RCA circuits can be just as good S/N as compared to XLR balanced....I guess it depends on the individual component circuit quality as much as anything. In any case, once you get to S/N of 110+ db which is often the case in high quality gear ...it becomes academic if it is RCA or XLR as you can only hear the noise with no other sound from the speakers and the volume cranked up and your ear at 6 inches from the tweeter!!!

Of course, the above comments are for short runs and for a normal environment where you don't have a problem with EM noise pick up (lots of cables/transformers etc. all close together).
Tvad, I talked to one of the cable tech.rep last week and you were right on the fact that they did not know for sure what the heck they are talking abt. As a consumer, the " I think..." does not not worth a "shot" to me. They dance around the issues as good as their sales rep.
Well, the concept of noise reduction is the basic theme of XLR/balanced cable, and that point is the "take away" regardless of how badly anyone messes up the explanation of how it is achieved. At least, that's my approach as an end user. If I owned equipment that was all truly balanced, I'm certain I'd use balanced cabling. However, as it stands, I use all single ended cabling, and I have absolutely no issues with noise due to the RCA interconnects.
rats:[Quote]In the case of mono amps with single ended inputs they will share the same circuit ground, they are connected together at the single ended source, ie. pre-amp.[Quote]Steve, you missed the point. The right channel circuit will contain only the right channel interconnect and right channel amplifier. The current in the ground wire of the right channel interconnect will be equal in magnitude to the current in the right channel positive wire of the same interconnect, just in opposite phase. The same would be true for the left channel, so the electrical balance condition is maintained, just like in fully-balanced systems.
The question here isn't whether Andrewdoan should buy components with balanced circuits, since he already owns them. Anyway, in home audio this choice is rarely about reducing overt noise levels. For a combination of reasons -- running true-balanced is capable of reducing not only induced noise, but also self-generated noise, and in some cases distortion too -- the pertinent point is that the sound of the music might be improved by using balanced connections when running balanced gear, even if you never hear the result as being 'noise-reduction' per se. One of those reasons is that internally-balanced gear typically subjects unbalanced input signals to an additional circuit stage in order to convert them to balanced for processing, and this extra input stage is bypassed when using a balanced connection. (Conversely, gear that isn't internally balanced, but merely has XLR jacks wired in series with its RCA jacks for the sake of convenience, will often sound better with single-ended connections, which dispense with the extra jacks, wiring and solder joints at this small-signal juncture). So the answer to the question at the top is that there is no one right answer, it depends on the gear -- and with gear that was designed to make full use of a balanced connection, it makes sense to try one.
I hope the following issue will not lead to another subject: We agree on if using XLR connections with fully balanced circuit there is an increase in sound pressure level abt 6 db. If I use 4 ohm speakers, then according to spec, my amp will operate at 400 watt. With 6 db increase in SPL by using XLR connections, would my amp operate at 400 watts x2 x2 = 1600 watts per channel. Keep in mind abt the fact that every increase of 3db in SLP requires double in wattage to produce such 3 db increment. Simple math but does not sounds logical. Any thoughts?
Very good Serus, thanks!

steve
Andrew, no, no one agrees with that statement. The designer is free to apply any amount of gain to any particuliar input, he could just as well cut the gain in the xlr input by some amount compared to the rca input.

steve
Andrew: The SPL is determined by the volume control setting. (We needn't go into the subject of dB's, watts and ohms, but suffice to say that it's not as you suppose.) Anyway, don't worry about any of this -- everything will behave as it did, except that you may find your preferred volume setting to be a couple clicks lower.
I have not read the whole thread as it is a little long, so I hope I am not repeating what's been said. I recently attached balanced cables to my sim pre to sim power amp, and have to say the difference is tremendous. I plan on getting a balanced phono preamp now.
It depends on your component's circuit. Some are made single ended and can be used balanced...some are made balanced and can be used single ended. Find out from the manufacturer how it was designed and use it in its preferred configuration

06-20-06: Chatty1
It depends on your component's circuit. Some are made single ended and can be used balanced...some are made balanced and can be used single ended. Find out from the manufacturer how it was designed and use it in its preferred configuration

true that!!!!