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The Balanced vs Unbalanced Debate


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For several years, I have had the same setup of KDSM-->2xSolos-->2xSolos-->Sonus Fabers as a passive bi-amped configuration, with one pair of Solos connected to the higher frequency speaker terminals and one pair connected to the lower frequency terminals. Since the Solos have to be piggy-backed, they can only be connected together with unbalanced RCAs, and hence the KDSM had to also connect to the first pair of Solos with unbalanced RCAs. 

I have decided to simplify things and remove a pair of Solos which I intend to deploy elsewhere. I am furthermore looking at speaker upgrades that include several possible models that do not accommodate bi-amping.

Now I have the option of balanced or unbalanced between the KDSM and Solos in my main system. I will naturally experiment  - I have Vertere Pulse-B cables in both RCA and XLR forms. I have read various debates on the virtues (or not) of balanced vs unbalanced, and the associated system/component dependency. I would be interested in the opinions of this group, particularly as I notice that Linn has been supplying KDSMs with Silver RCAs for some time, which I assume is for a good reason. If I recall correctly, my first ever KDS (2011) came with XLRs.

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As I see it, a truly balanced circuit is primarily beneficial if your interconnect lengths are more than about 1-1.5M. Longer cable lengths can more easily pick up noise, hence the balanced circuit which rejects common mode noise using differential versions of the same signal down two signal carrying wires which share the same impedance to ground. Any interference picked up by either wire is effectively ignored.

In addition a balanced circuit tends to have more headroom (I believe 6db is the figure often used) over an RCA (single-ended) circuit.

So, ignoring sound quality differences for the moment, one would want to use a balanced connection primarily for longer cable runs to equipment (in HiFi I'd avoid running RCAs longer than 3M/10ft if at all possible).

Of course the caveat is "truly" balanced, as many "XLR" connections are not fully differential, and use polarity/phase inverters on the transmitter/receiver circuits to convert the differential signal back to single ended internally.

As far as I am aware Akurate and Klimax equipment, in addition to having RCA single-ended outputs/inputs which sound excellent, do use a fully differential topology for the balanced XLR connections, and in my personal experimentation and auditions I have always preferred the balanced output of a Klimax DSM to the RCAs, with Solos or a Twin, even with a shorter length interconnect.

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Posted (edited)
On 04/06/2021 at 08:11, rad1 said:

For several years, I have had the same setup of KDSM-->2xSolos-->2xSolos-->Sonus Fabers as a passive bi-amped configuration, with one pair of Solos connected to the higher frequency speaker terminals and one pair connected to the lower frequency terminals. Since the Solos have to be piggy-backed, they can only be connected together with unbalanced RCAs, and hence the KDSM had to also connect to the first pair of Solos with unbalanced RCAs. 

I have decided to simplify things and remove a pair of Solos which I intend to deploy elsewhere. I am furthermore looking at speaker upgrades that include several possible models that do not accommodate bi-amping.

Now I have the option of balanced or unbalanced between the KDSM and Solos in my main system. I will naturally experiment  - I have Vertere Pulse-B cables in both RCA and XLR forms. I have read various debates on the virtues (or not) of balanced vs unbalanced, and the associated system/component dependency. I would be interested in the opinions of this group, particularly as I notice that Linn has been supplying KDSMs with Silver RCAs for some time, which I assume is for a good reason. If I recall correctly, my first ever KDS (2011) came with XLRs.

Very interesting topic!

I agree with @Elad Repooc that one would expect the symmetrical connection to sound better. But then, more components mean more room for "parasitic effects", and how symmetric is the symmetry in reality?

My trusted dealer once claimed, that RCA usually sounds better. But then, how can we compare this. A Klimax Exaktbox only has XLR connectors. Akurate amps have either XLR, or RCA connectors. If it can be demonstrated, that RCA Akurate amps sound better than their XLR sisters driven by a Klimax Exaktbox, it would be a compelling case towards RCA. This could be double checked by swapping the Klimax Exaktbox with an Akurate Exaktbox, and using RCA into RCA vs XLR into XLR. If RCA still wins, I'd be convinced to bet on RCA with standard cable lengths.

Did anyone attended such an auditioning?

Edited by TooManyCatweazles
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I will do some auditioning of RCA vs XLR between the KDSM and the Solos which have both output and input options. The problem (IIRC) is that the XLRs may sound louder. And louder is better, right?! So proper A-B-A auditioning may be a bit confusing.

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This general note on balanced inputs may be of interest https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces

Regards Andrew 

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Posted (edited)
1 hour ago, andrew s said:

This general note on balanced inputs may be of interest https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces

Regards Andrew 

Interesting read! But it contains sort of a disclaimer by cautioning us, that pro gear uses higher voltages at the XLR outputs, than regular hifi gear.

Interestingly, the paper also discusses the value of transformers vs differential amplifiers on the XLR input (to facilitate common mode rejection). I recall, that the Klimax Exaktbox uses transformers in the XLR output. Looks like they are redundand for a symmetrical connection (but maybe still valuable to connect to an RCA input), in the context of this paper.

I'm getting more nervous, whether I should replace my power amps by amps with balanced inputs?

Edited by TooManyCatweazles
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6 minutes ago, TooManyCatweazles said:

I'm getting more nervous, whether I should replace my power amps by amps with balanced inputs?

What explicitly worries you? Regards Andrew 

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Posted (edited)
42 minutes ago, andrew s said:

What explicitly worries you? Regards Andrew 

Being trained like Pavlov's dog by Linn's summer promos, I'm getting the update itch by the end of meteorological spring, and the weather suddenly flipped into summer mode last week, over here 😉

My C6100 (RCA) has aged well, anyway, and replacing it might be an obvious option. After all, my frontend, and middleware received huge improvements since I bought the amp. Thus, the RCA vs XLR question looks like an important fundamental decision. I had been offered a used A4200 (XLR) recently, but ditched it 'cause combining RCA and XLR amps won't work well due to their different gains.

Replacing the RCA C6100  by a XLR C6100 could be a helpful intermediate step to open the opportunity for further 'real' improvement steps. This swap would need little investment, and pave the road towards future Ax200 upgrades - or whatever new amps Linn might surprice us with.

As I put a lot of trust in my dealer's opinion, his word (RCA usually sounds better) contrasts our discussion here, and I would love to hear the difference myself.

Another way to play this could be, to buy a used XLR 6100, and compare it to my RCA 6100. I have 3 pairs of Linn Silver IC XLR in my drawer, so it would be a fair comparison. Could sell the loser afterwards. 🤔

These kind of thoughts are what I ment by "getting nervous".

Edited by TooManyCatweazles
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Here's a video that explains the difference:

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8 hours ago, TooManyCatweazles said:

My trusted dealer once claimed, that RCA usually sounds better.

In the past this would have been in line with the Linn philosophy, and was highly applicable to Linn equipment at the time because the requirements for a typical domestic HiFi (in terms of location of equipment) is generally not something worth warranting the additional expense of having a fully differential circuit. Other than the top Linn CD players and Preamps/Processors, they avoided including balanced "just to have it" whereas plenty of other manufacturers touted balanced connections as a guaranteed improvement. I would say up until about a decade or so ago the idea that the RCAs sounded better in most applications was the general consensus amongst most "Linnies".

As a case in point, a number of years ago, after a customer of mine had upgraded to a Klimax DSM and Urika 1, we did a comparison between the XLR and RCA outputs on the Urika 1 being fed into the DSM, as well as between the Klimax DSM and the Klimax Twin he was using. First we listened just to the difference between RCA and XLR on the DSM/Twin, and after several back and forth TuneDems we determined the XLR sounded better. This customer had previously also sold Linn for a number of years and so he was familiar with the Linn philosophy in the past, as was I, and his expectation was that the RCA should have sounded better, but we ended up using the XLR connections. However, when we compared with the Urika 1 > Klimax DSM we both preferred the RCA connection for that (it was a somewhat difficult comparison to make as we had to use the LP12 setup jig to accommodate the swapping of the cables). Actually in the latter case it wasn't entirely subtle, I felt that it was a bigger difference to use the RCA connection between the Urika 1 and DSM, than the slight improvement we heard over the RCA connection when using XLR between DSM and amp.

In other words, if pressed I probably wouldn't say the difference between XLR and RCA connections with Linn equipment are something drastic, but really probably has more to do with application - i.e., if your amps/Exaktboxes are far away from the DSM (there are practical as well as aesthetic reasons as to why someone might want to keep the amplification equipment away from the source equipment), then of course just use XLR because your cables are going to be long. Otherwise, the performance of both the single ended and balanced connections on Linn gear tends to be pretty close, the exception I've heard so far is the Urika 1. I'd use RCA for that if I had one, and only XLR if I wanted to keep the deck 25 feet or more away from the rest of my HiFi.

I would guess that the slightly increased awareness with respect to Active speakers (many, if not most have XLR connections) as well as the ability to interoperate better with different types of gear is what led Linn to including XLR as an option on Selekt DSM on up. There are many amplifiers from other manufacturers where the XLR circuit is either the only option, or it simply trounces whatever RCA circuit the manufacturer slapped in the box. When it comes to Linn, the differences are more subtle, but I think the OP will find that the balanced connections between KDSM/Solos tends to sound a bit more effortless.

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@akamatsu

I only got about 20 seconds into this video before I had to laugh a bit. Amir says that it's one of those "confusing" topics.
 
Anyone who has been to school for audio engineering or production work would laugh. It's not confusing at all. Balanced connections are used to reject common mode noise picked up by the cable over long lengths.  
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Just now, Elad Repooc said:

@akamatsu

I only got about 20 seconds into this video before I had to laugh a bit. Amir says that it's one of those "confusing" topics.
 
Anyone who has been to school for audio engineering or production work would laugh. It's not confusing at all. Balanced connections are used to reject common mode noise picked up by the cable over long lengths.  

I think he meant it's confusing for a lot of people. I think his explanation was very simple and straight forward.

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Amir claims that balanced "topology" versus a balanced "input" on audio equipment and a balanced "headphone" connection are three separate things. 

This should get interesting.

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Quote

I think he meant it's confusing for a lot of people. I think his explanation was very simple and straight forward.

 

I have to disagree at 10 minutes into the video. This is not a straightforward explanation of what is meant by a balanced circuit. I am more confused now, than I was before watching. He claims that what is happening on the headphone output should not be called balanced, but "differentially driven". It's the same thing! If you read John Siau's explanation on Benchmark's website as linked above, it will be plainly obvious that Amir is muddying the waters here.

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