When to choice XLR over RCA ICs.

@cleeds - RE:

If all else is equal and the cables are being used between truly balanced components, I can’t imagine a scenario where unbalanced RCA connections could be better than balanced connections.

Unfortunately all things are not equal because of the following...

• The best low mass RCA connector is significantly better at transferring an audio signal than the very best XLR connector is able to achieve - i.e. at present
• Then there are the insulations and cable geometries, which can only really be "equaled" with a very custom cable build
• even then the number of conductors in an XLR cables can cause noise issues within the cable itself. This noise is not canccelled out by the balanced processing of the +ve and -ve signals in the component because it resides on the neutral conductor, which impacts circuit performance

OK, so even with the very best cables we are talking miniscule differences here, but the signle ended RCA interconnect for a 1-2 meter cable will always be just a little superior to an XLR ables of a similar design/geometry/build.

Due to the complexities of cable design there are very few people that will step upto the task of designing/building cables having their own geometry.

So, for the most part the XLR cable will "generally" prove to be superior.

But if you are into custom built cables having their own noise supressing geometry you can spare some expense by building a single ended cable that will better the performance of a similalrly designed XLR cable.

Unfrotunately, since the internal design approaches between the XLR circuit and the single ended circuit within a component can vary, actually proving which is better is incredibly hard, especially if the component’s design is based on a balanced approach and the RCA is there just to accomodate a customer perceived preference.

Regards - Steve

williewonka

The best low mass RCA connector is significantly better at transferring an audio signal than the very best XLR connector is able to achieve ...

Hmmm, that's quite a claim. It's not too difficult to buy XLR connectors that are essentially electrically perfect, so I don't see how it's possible to get "significantly better" than that.

... the signle ended RCA interconnect for a 1-2 meter cable will always be just a little superior to an XLR ables of a similar design/geometry/build.

Not when used between differentially balanced components that yield 6 dB better gain (or s/n) when operated in balanced mode, such as ARC.

@cleeds - re:

williewonka

The best low mass RCA connector is significantly better at transferring an audio signal than the very best XLR connector is able to achieve ...

Hmmm, that’s quite a claim.

The KLE Innovations RCA have always been outstanding RCA connectors and according to others that have compared them to some very good XLR connectors on cables of similar contruction methods and maerials, the KLEI RCA’s performed better.

• This goes back abut 7 years and the KLE Innovations RCA have continued to get better in that time

RE:

Not when used between differentially balanced components that yield 6 dB better gain (or s/n) when operated in balanced mode, such as ARC.

In my view, an extra 6db gain does not result in improved dynamics, clarity and details - it’s just louder

Since personal preferemces tend to play a large role in cable selection e.g...

• I’ve known people that prefered using Duelund tinned copper over pure OCC copper, just because it sounds better to their ears
  • technically, OCC is faster and less prone to the timing distortions that occur when you mix two types of metal

But debating the differences between XLR and RCA for a high performance cable really is a moot point, however...

• people should be aware that the differences really are miniscule in high quality cables today, so opting for RCA is not really settling for second best any more

If a person really wants to improve their sound by replacing cables then I would really recommend they follow the link included in my first post above which covers the improvements that can be achieved by ensuring their cables use modern geometry, improved metals and insulations and state of the art and connectors.

Regards - Steve

williewonka

... an extra 6db gain does not result in improved dynamics, clarity and details - it's just louder ...

No, it's not just "louder." For the same output level, the differentially balanced connection (such as with ARC) will yield a 6 dB better s/n.

... the signle ended RCA interconnect for a 1-2 meter cable will always be just a little superior to an XLR ables of a similar design/geometry/build.

Why would I forsake that 6 dB gain (or s/n advantage) in a connection such as between pickup arm and phono preamp? That makes no sense. And there's no way your unbalanced connection can equal the noise rejection of a balanced circuit. That's why we have balanced circuits.

In my view, an extra 6db gain does not result in improved dynamics, clarity and details - it’s just louder

Since personal preferemces tend to play a large role in cable selection e.g...

• I’ve known people that prefered using Duelund tinned copper over pure OCC copper, just because it sounds better to their ears
  • technically, OCC is faster and less prone to the timing distortions that occur when you mix two types of metal

But debating the differences between XLR and RCA for a high performance cable really is a moot point, however...

• people should be aware that the differences really are miniscule in high quality cables today, so opting for RCA is not really settling for second best any more

No, it's not just "louder." For the same output level, the differentially balanced connection (such as with ARC) will yield a 6 dB better s/n

Why would I forsake that 6 dB gain (or s/n advantage) in a connection such as between pickup arm and phono preamp?

@williewonka @cleeds The 6dB increase in volume only occurs if the balanced line standard is ignored.

For example in the case of a phono cartridge, the output level does not change if the cartridge is operated either way. IOW the cartridge when operated balanced, conforms to AES48 (the balanced standard).

But if operated balanced, you have up to a 6dB improvement in the signal to noise ratio of the gain stage itself. You also have the rejection of noise that is common to the non-inverted and inverted parts of the signal. So a power transformer by the cable is far less able to induce hum into it.

The 6dB improvement in signal to noise of the gain stage is theoretical. The greater the differential effect that is winnowed out of the gain stage the more you approach that possibility. To that end, and this is directed at cleeds, the constant current source feeding the differential amplifier is the key to the differential amplifier's performance. So if you wanted to improve your ARC preamp's performance this would be the thing to investigate. 

I see the really big advantage of balanced lines in that you don't have to have an expensive cable with exotic materials for it to sound just as good as a cable that does have the exotic construction and materials. IOW you get cable immunity. I've demonstrated this many times over the last 40 years.

Where this really plays out well is the tonearm cable! If there is any place to really get it right, this is it, because no matter how good your preamp, amps and speakers are, they can't make up for any losses to the signal upstream.