XLR vs RCA

I am with Warrenh. Even though Audioengr's points are valid, the last one is the biggest concern with balanced systems, the impossibility of designing a truly balanced system.

A system that is balanced from beginning to end is actually two chains of amplification. From source to preamp to power amp you have one string of amplifiers amplifying the inverted signal and a different string of amplifiers amplifying the non-inverted. These two signals are combined at the speaker. Even though they should be the same, with tolerances in components it is impossible to build two identical amplifiers.

It is highly unlikely that both signals will be treated exactly the same throughout this process so the reconstructed signal at the speakers is distorted. Yes, there are distortions in single ended systems like in all systems, but this one introduced by the balanced systems is not present in a single ended system.

Also, digital signals start out being single ended on the disc and must be converted to balanced somewhere along the path. This is another source of distortion.

As for noise rejection, balanced does have the theoretical upper hand on long lengths of cable. But with cable lengths and the amplitude of the signals in a typical system you could not tell any difference.

Like many other topics in the world of high-end audio this one is controversial. Balanced lines have been around for a very long time now in the pro-sound world due to the extraordinarily long cable runs often necessary for studio, stage and performance. With cable runs sometimes in the hundredes of feet noise becomes a real issue. But most audiophiles are rarely using runs that exceed 20 feet. Jeff Rowland was one of the first in high-end audio to use true balanced circuits in his amps and preamps and does so to this day as he feels it to be superior. And his gear is certainly dead quiet, not to mention some of the finest sounding gear available. Balanced Audio Technology has also been very sucessful with their balanced amps and preamps. Be aware, however, that while some manufactures have balanced XLR lines in and out, these may not be true balanced circuits such as those used by Rowland and may offer no sonic advantage and may very well not sound as good as the single ended inputs and outputs on the same piece of gear.

Another very significant point, and herein lies the controversy, is the number of truly excellent and highly regarded amps and preamps that only come single ended. Names such as Convergent Audio Technologies (CAT), Jadis, Brown Electronic Labs (BEL), Audible Illusions, Joule Electra, and Blue Circle Audio, just to name a few, come to mind. I personally have owned many many components over the years and have had systems that were fully balanced (except my turntable), but most that were not. I also have been using 16 to 18 foot interconnects between my preamp and amp for over ten years, and to date the best systems I've put together have been single ended. In the end I believe you will find it is the component itself that makes the difference, not whether it is single ended or balanced. My advice is to choose the components you like the sound of using your ears rather than someone's sales hype. No matter what you say or do there will be those in the balanced camp and those in the single ended camp. Neither is right, neither is wrong, just different approaches to the same end. All of this stuff sounds good, the trick is finding out what your preferences are and working toward finding components that are a synergistic match with each other.

Great posts, but Herman I don't undersatnd how balanced operation results in UNbalanced summation at the speaker...any more than a single-ended design. It's pretty clear that preference is component specific. My EMC-1 MkII CDP, for example, sounds clearly better running balanced.
As my Aleph P and monos are running truly balanced, I can get away with longish UNshielded XLRs (Nordost) with utter quietness and VERY fine low-level detail resolution. Would I have the same result with RCAs? Haven't tried, but don't want to, either...especially with the house breaker panel under the same room. Shades of grey, eh?

Hi Subaruguru, I said they were combined at the speaker. Not that they were unabalanced. The electrical signal that is applied to the speaker terminals is balanced but the motion of the speaker is not.

Each driver can only move in one direction at a time, The cone is either moving in or it is moving out but can't go both ways at once. So in that sense it's motion is single ended.

I agree that there are well designed, great sounding components in each camp. Since I am firmly in the camp that simpler is better, I'm going with single ended. I'm using a passive preamp, my power amps have 2 tubes each, and my speakers only have one driver.

I was using the balanced outputsof my Electrocompaniet EMC-1 into the balanced inputs of my integrated amp (a non-fully balanced design) and it was an improvement over the use of RCA connections. Then I switched to a different preamp (passive) without balanced connections and I think it sounds even better. It seems to depend on many things.