RCA vs XLR findings/questions...

Experimenting with RCA (QED Performance) and balanced XLR (Cambridge Audio AUD900) interconnectors between my amp and CD player the other day (both Cambridge Audio 840), I that found the latter had a fairly un-subtle effect on the channel separation with a more defined soundstage, and also added a bit more kick to the delivery.

I wondered if it was just the effect of the extra apparent ‘loudness’ from the XLR at all, so reduced the gain on that input to get the same level as the RCA one (you can trim/tailor the gain on each input with the 840a, and I had both interconnectors running from the CD player to different inputs at the same time so could just switch between them), but the differences were still there.

To be honest I’ve never believed interconnectors themselves much difference at all so long as you’ve got a decent quality one, hence the basic QED RCA that I’ve stuck with. I only got that particular supposedly good/expensive XLR one as they offered it me for half price when I got the CD player to match the amp, otherwise would have got a more basic one.

So I guess my questions are, if anyone can help:
- Is the difference I noticed more likely to be a result of it being a) a balanced connection (which I’m assuming); b) ‘better’ cable in general… or both
- If it is the balanced XLR connection making the difference, then why do some mid-high level equipment not offer it? Specifically I’m thinking about my friend’s Naim Nait XS/CD5i combination which sounds bloody brilliant!, but surprised me for not having it as an option…

Rob

 

Thanks for the report. Personally, I've never placed much faith in these XLR connectors, and have actually avoided components that compel you to use them over the years.

 

My pleasure. I hadn't all that much faith/expectation in them either really; but then as well as heavily discounting the XLR connectors, the store also offered a no-quibble refund on them within 40 days if I didn't notice any difference. Couldn't say fairer than that!, and I'd have happily taken them back if there wasn't the improvement that there honestly is.... in this example at least

 

To determine whether you are hearing the effect of the cable, or the balanced connection, you would need to use the same cable for both connections, to remove it as a variable.

Why isn't all gear balanced? Because getting very accurate balanced circuits is not easy/cheap. What you gain in noise immunity, you may lose in distortion due to imbalance. There are some designers who believe that they can get better sound quality from a single ended system. In a harsh (electrical/RFI/EMI) environment, or where long cable runs are required, balanced rules.

So, no hard and fast rule, one must listen to both and decide for oneself.

 

I'm no expert on this but I would rather have though it's down to the equipment at either end of the cable. Gear that's fully-balanced in design is probably going to benefit from using XLR as it is designed to do so. Gear that isn't fully-balanced in design is at the mercy of the input/output transformers that provide the balanced ability. These can be an afterthought and actually sound worse than the RCA connections, but good ones should sound better. Output transformers can also mean the volume levels differ with regards to balanced vs unbalanced and can make comparison more difficult.

With my Linn Klimax DS/pre-amp gear, it's not fully balanced in design but the Lundahl transformers on the XLR connections mean it sounds slightly better than RCA to me. Opinions vary just between those bits of kit so it's really down to your ears, but don't fall for the trick of one method sounding louder than the other.

 

I always use XLR's when possible, but it's mostly because it's a better connector than RCA from a mechanical viewpoint. I simply like the more solid feel.

 

Yep. I agree with this whole post but the opening sentence that I quoted here cuts to the chase in the OP's present situation regarding A/B comparison. I further agree that not all circuits are created equal and for the most part have found that a good SE circuit is better than all but the best of balanced implementations.
-Bill

 

Agree with need to use same wires to compare.
I like XLR and RCA. no problem with either. I do use the XLR for pre to amp as that cable is 7 meters long.

 

Steve, I would love to know why.

Do you dislike the connectors themselves, or the balanced strategy?

ccm

 

I disagree with Steve and do use XLRs, provided there aren't tons of internal transformers in the signal path and the specific component(s) are designed for balanced 3-wire connections. Every studio on earth uses them, particularly when long-length analog cables are unavoidable.

http://en.wikipedia.org/wiki/Balanced_audio

I would agree with Steve if this was a consumer audio product that just jammed an XLR in there from the same connections, used some kind of crap transformer, and still used -10dB signals. If it's a real +4 pro audio component, then you'll see real benefits from an XLR connection. But... that's a big if.

 

Hi all - thanks a lot for the thoughts/comments. Interesting range of views and experiences.

Totally agree it would be ideal to compare XLR/RCA versions of the same cable, but that wasn't an option to hand unfortunately. I think what I was trying to ask was do people think there's more difference between different inconnectors, or (all else being equal) between balanced and unbalanced inputs.

I might well try the RCA version of the XLR cable I have (my RCA going between phono-pre and amp), and perhaps other models, and it'll be a keeper if it has the improvements as described above... and at that point I would really have to drop my stubbornly-held belief/assumption that interconnectors make no difference!

If the difference does turn out to just being XLR-specific though, then again I'd wonder why some manufacturers don't include it in their otherwise well-specced gear; though Black Elk, Rufus, KT88, and Vidiot touched on the variations and complexities there. From what I remember, Cambridge make a big deal on the balanced aspects of their 800 series, so maybe it does pay off on this particular set-up.

And yes, would also be interested in hearing more on your XLR-avoidance Steve!

Cheers,
Rob

 

Why is it not good?

 

Stereophile wrote a good piece a number of years ago about why it was hard to make fully balanced better than single ended. I think it's in their posted historical articles.

CJ

 

Because you need additional circuitry or a transformer on each end of the line. Unless you need to drive a long line or have to interface with other balanced gear, I generally prefer the unbalanced connections.

 

Ok, I see. Thanks for that.

 

I feel better now!

I agree: some consumer gear has "phony" XLR connections that just go through a transformer, and it's not really kosher.

 

The XLR connector and its attached cable can be used for balanced or unbalanced signals and there is a lot of pro, semipro and other equipment that does exactly that. I was unaware of any halachic significance of doing so but electrically it isn't wrong or dishonest.

Mechanically the XLR is the best audio small signal connector design in common use. It should be noted that technically what we call an XLR really is not, it is compatible with one of the many XLR configurations Cannon made, though.

The RCA on the other hand is an unfortunate legacy that should have went away in the sixties, but we are pretty well stuck with it today. The quarter inch "phone plug" is actually a lot better.

 

The truly balanced gear I own/have owned has been a revelation when using XLR. I would avoid using XLR on any gear that uses pseudo-balanced outputs/inputs, which is most consumer gear out there.

 

Even if not balanced, the XLR connector is superior to the RCA connector. The Lamm amplifiers I own are single-ended but sport both RCA and XLR sockets (only one can be used at any one time). I would rather use the XLR connectors.

 

Yes, I wasn't thinking about transformer-balanced outs. All my gear is true balanced.

I have heard great sound from both single ended and balanced configurations.

I mostly use balanced out of paranoia about power cord electric fields behind the system. However, I do eventually plan on using longer IC runs to my monos once I move the system out from between the speakers, as per the recommendation of Jim Smith's book and DVD, Get Better Sound. I expect that balanced will serve me well in that application particularly

ccm

 

Can you cite an example?

I would expect that to be more common with vintage pro gear with input and output transformers, but all single-ended in between.

 

Hi Burt,

What would you say is the best audio small signal connector in UNcommon use? I often wonder if I should eventually just man up and replace my RCA connectors on the back of my gear with some good quality BNCs.

ccm