Another Balanced XLR vs. single-end RCA question

Cables
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At the recent AXPONA show, I had the opportunity to meet Ken Stevens of Convergent Audio Technology - I understood about 52% of what he said because I’m not an engineer. I asked him why he didn’t use balanced outputs for his pre-amps. I couldn’t begin to quote him exactly, but he said basically it’s not better.

I have an old, but still good CAT SL-1 Reference pre-amp. I also own (still pretty new) the PS Audio Stellar M-1200 monoblocks and the documentation recommends strongly to use balanced cables. With my previous amp that had only XLR inputs, I bought a cable that converts RCA to XLR, but I figured it didn’t improve anything - just got the signal from point A to B. I’ve since read that using this kind of cable can actually be damaging to the amp (I’m just using good RCAs now). But in the same article from Moon Audio, the author states that the advantage of XLR is to reduce noise, mainly in longer cable runs, but the only way it might improve the signal itself over single-ended is if the entire pre-amp and amp are balanced all the way through. So given my system, I’m thinking the only reason to do XLR would be noise-reduction, but the distance between my pre and amps is only 2 feet.

Finally, I just saw a single-ended to balanced converter for $275. I trust the stuff from Pine Tree Audio, but I’m wondering whether this could even possibly provide anything of advantage. Yeah, I know, buy it and listen, but curious about other opinions. Anyone else here go from a good single-end pre-amp to an amp and found any difference in sound by switching to XLR?

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Don’t obsess over the single-ended/balanced debate. There are other authoritative voices in the industry that have argued on solid technical grounds the real question is how well either type of circuit is executed, not whether it is single-ended or balanced. Two that come to mind are Frank Van Alstine and Keith Herron. There are others. The arguments are 1) balanced topology was originally developed for professional applications where very long cable runs are the norm - far longer than is typical in any domestic audio environment and 2) a balanced circuit is more complex, has a higher parts count, requires especially tight tolerances and is more expensive to manufacture. Another mistake is assuming because a component has a XLR connector it must be balanced. Nope, not true. Sometimes that is a convenience offered by the manufacturer for users who have a significant investment in balanced cables, but in fact only the positive leg is routed to the single-ended circuit. Ken’s point is well taken - CAT has been lavishing great care in the design and execution of world class single-ended audio gear for years. Bottom line: I’ve compared both topologies and conclude there is no pat answer to which is best. If the gear is designed from scratch to be state of the art single-ened, it will be just that.

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Hey thanks for the quick reply. You’re saying pretty much what I’ve read in other places as well. I guess when I got the CAT, I had no idea anyone used XLR for home audio (I used to work with them in recording and radio). But if RCA is good enough for CAT, must be good enough for me.

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When I had my BAT pre/amps setup. I had both Purist Audio RCA and Balanced interconnects (same model but forgot what).

They did not sound the same, but it was due to the type of connectors, I believe. RCA sounded warmer was all I remember. For longer length balanced cable has advantage (Paul has an “ask Paul” video explained it).

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The Moon Audio article I mentioned in my starting post said that in certain cases the RCA can actually be better because it can often provide a stronger signal - noisy if you’re not careful - but be careful.

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It could be. Many hi-end Japanese gears only provide RCA connecting option.

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When i have the BHK pre connected to the M1200’s i use XLR interconnect. When i have the Conrad Johnson preamp connected to the M1200’s, i use rca interconnect (CJ only uses rca). Since your preamp uses only rca, then use rca interconnect between your preamp and the M1200’s.

I should add that the BHK pre has both rca and XLR connectors. With the BHK pre, I definitely WANT to use XLR as the main connector to the power amps. But i also use the rca out at the same time, sending signals through rca to the subwoofers.

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I talked with Ken for 45 minutes. We both really enjoy bunny rabbits so we didn’t talk much about audio.
When somebody gets all balanced vs non balanced on me I excuse myself. With less than 2m cables the point is moot. Moot I say.

[I only use balanced]
[duh!]

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@JLawry There are many theoretical advantages of XLR over RCA. However, if these really apply to your system, is the big question. You might run a system with high quality components and relative short interconnects. So these advantages might be negligible.

Theory XLR vs. RCA:
The XLR cable design provides several advantages over unbalanced RCA cables as audio interconnects. These benefits include improved resistance to electromagnetic interference and noise, resulting in a clearer and more accurate sound. Additionally, they have lower impedance, which can lead to better signal transfer over longer distances.XLR cables also offer greater common-mode rejection, which means that any interference that is picked up by the cable is more likely to be cancelled out, rather than being amplified along with the signal.

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What he said!!!

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I actually have one of these Pinetree Audio components but had it built in reverse–to convert balanced to RCA with the full gain of the balanced. I use that to convert the balanced output of my modded DSD DAC into my Decware ZROCK2 with its RCA inputs, and then into my Decware Taboo Mk IV headphone amp (it’s a fantastic speaker amp as well, but only used for headphone use currently).

The Pinetree piece is a very nice one. I am sure it would be a bit improved for transparency if it were to use further up the ladder Jensen 1:1 transformers as the Decware ZBIT I have in two other systems does, but it does little damage to the signal in any way. And with the better transformers the price would probably more than double.

In my systems all my amplification is without balanced input so these devices allow me to feed the amps with the full voltage of the balanced output of the DACs and this gain is beneficial in several ways with my low powered amps.

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XLR are better when the signal deficiencies are offset by noise advantages. Balanced have a percent of CUB, Capacitance UnBalance. The two “halves” are not created equal and change the SIGNAL, it has to as they are subtracted to cancel the noise (common to both sides). And yes, that means noise isn’t 100% “gone” either! Noise has to be 100% the same on both wires, and the signal noise has to be 100% equal and opposite on both wires. CUB means it is not the case. I won’t get into the balance of the driver op-amps but they aren’t all equal and opposite either. Very good but this is a system of analog interfaces to get right. Errors keep adding up.

In cases of extreme noise, with the added benefit of low frequency noise rejection of XLR and long distances, CUB distortion can be less an issue than what happens to the signal with balanced designs. As a plus, attenuation on XLR is good (different driver amps) so any loss there is mitigated. No cable is 100% balanced.

An added outer shield makes CUB WORSE. It magnifies the ground plane differences and the impact it’s on CUB. But, if the NOISE is attenuated 100dB by the added shield this offsets the increase in CUB distortion.

That no cable is 100% balanced means that the passive CMRR, Common Mode Rejection Ratio isn’t “perfect”, either. That is determined by the physical geometry of the cable as much as the signal balance.

RCA are 100% accurate on the signal side, there isn’t a “balance” to get right. But, they can’t shield low frequency magnetic noise like XLR. For RF, they are actually better with a proper low transfer impedance shield. A foil braid or double braid is 100 dB shield isolation to RF per SEED Shield Isolation Device tests.

For shorter runs, most of us, RCA is actually better most of the time signal wise. But, if you have audible noise, the small CUB impact of an XLR is worth the trade-off to remove audible noise. A studio can’t chase noise all over so they are 100% XLR as any noise is far worse than what happens to the signal.

For longer runs, 20 feet or so, go XLR as the advantages to the signal amplitude impact Attenuation to CMRR balance noise more and more.

And yes, a lot of equipment use the Pin 2 and Pin 1 as a cheater on an XLR plug for your convenience to use an XLR like a RCA. But it isn’t great to do this as and XLR isn’t as good as an RCA in that situation. But, if you don’t have NOISE (there is no more XLR balance wired Pin 1 and 2) all is good.

DO, DO, DO match your cable to the inputs provided; balanced or unbalanced. Do NOT buy XLR and wire for RCA, you forfeit the advantages of either cable! If you could wire and XLR to ever be as good as an RCA, why would we even have RCA? An RCA minus magnetic noise is better than an XLR on the signal side, no CUB. We just need to realize most of the time we don’t have magnetic noise.

If you do have many an XLR, and use the cheater plugs, for a short distance you may be fine (you have no more CMRR using just Pin 1 and 2) as the RF shield is still working and few have magnetic noise issues.

By the way, all outer shield are RF using copper and foils as they don’t have low permeability to magnetic flux. A magnet will stick to low permeability stuff. And yes, this is why XLR was applied as it uses a different method to remove what is called common mode nose (equal and opposite in each signal wire). That does include RF, too! The shield improves the RF CMRR but not the magnetic noise cancellation.

In short no cabe as 100% perfect balance over a length. But, the CMRR advantages insure no nise, and this offsets the CUB in studios. In home high-end audio, we want the SIGNAL to be “perfect” and RCA in proper lengths do that better outside of mismanaged magnetic fields.

As each cable has specific advantages, do use the native design inputs of your equipment as the two cable designs don’t play nice forced to be the other. This is the best answer to if an RCA or XLR is better. What is your equipment’s native I/O? They can decide that better than we can. Go with their designer’s answer.

Best,
Galen

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Great stuff, Galen

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Well said.

What, if I may ask, material or design features do the Iconoclast RCA cables employ to attenuate and/or prevent “low frequency magnetic noise” or other “audible noise”?

TIA.

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As far as magnetic “hum” rejection RCA design doesn’t have a defense. Few have hum with modern equipment and if you do, it usually means your ground points are not close enough to the same and you have a ground loop that needs to be fixed. I’d say 90% of noise is a ground loop and not induced magnetic fields.

For LONG lengths where the RCA shield (signal ground, too) DCR will raise the ground, XLR works best by design because the cable uses a floating ground between the plus and minus polarity signals so the ground is not impacting how the cable works. It is there for the shield ONLY, which isn’t the signal ground.

Best,
Galen

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Wow, what a surprise - that someone here actually HAS one of those things! But unless I am really missing something, trying to capture the XLR advantages and converting them to RCA would not be the same as your reasons for getting them to do this backwards.

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Thanks for the great explanation. I think you beat Ken Stevens in being able to penetrate my limited lack of understanding of all this.

What is your equipment’s native I/O? They can decide that better than we can. Go with their designer’s answer. <<

The CAT is RCA, the M1200s like XLR if the pre does XLR, but does RCA just fine. So that’s where I’m going to stay.

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I really can’t make sense of that sentence.

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Yet another set of experiences to offer here… Lloyd Walker was another designer/engineer who discounted balanced technology for all the reasons @owlsalum lists. And, while he was known for his turntable designs, he built some of the cleanest, most highly resolving preamps and phono stages in the business. On the other hand, Ralph Karsten of Atma-Sphere, Jim White of Aesthetix, Justin Wilson of HeadAmp, and Andreas Koch of Playback Designs are all strong proponents of balanced gear. I mention these designers only because I’ve owned great electronics designed by all of them. And I’d never hesitate to add a component designed by Ken Stevens – his products are wonderful.

My contribution to the discussion is simply that, when I have in my equipment rack complementary gear that is fully designed as balanced end-to-end and I connect them together using balanced cables, they do sound better than if I connect them using their unbalanced RCA outputs/inputs. To be clear on this: I am NOT saying they sound better than well designed single-ended gear. I’m saying only that each time I’ve had a full set of complementary balanced electronics and I then connect them balanced, my experience has been that they sounded better connected balanced than connected unbalanced. In my limited experience, there does seem to be a synergy here.

But, that would not drive me to purchase balanced gear just for having balanced. I’ve lived most of my audio life listening to mixed sets of electronics for one reason or another, with one item balanced and another single-ended. In this case they are connected via RCA cables. At the moment, all is balanced gear connected via balanced cables. But that may change with the next great component that I find needs to come live with us.

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That is so true. My gear is fully balanced end to end and I started with RCA cables throughout and it sounded wonderful, but when I put in the balance version of the same cable into the mix, it took the sound to another level. In my situation with the Esoteric gears, the difference was not trivial, it was quite a increase in clarity. Same when I use balanced out from the PS Auio DAC to my preamp, though I had to compensate for the 6db increase in volume from the balance output of the DAC.

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