We were the first company to produce a fully differential balanced preamp and power amp for high end audio. The amp was in 1986 and the preamp in 1989.
The reason we did it is because I had exposure to recording gear while playing in several orchestras in high school, college and after college. I saw that the microphones often had cables that were over 100 feet before their signal arrived at the tape machine. Somehow that didn’t seem to hurt the sound. About 1977 I also met Robert Fulton of FMI, who is the founder of the modern high end audio cable industry. As all of you know. At least if you didn’t, you do now.
Obviously he was claiming that cables made a difference, and he could prove it. But what I saw when my orchestra was being recorded was something different- the cable didn't seem to affect the sound!
That difference was the difference between balanced and single-ended. Turns out the phone company had to deal with sending audio over long distances and found that balanced was the way to do that; the recording and broadcast industries picked up on that pretty quick in the late 1940s and early 1950s, which ushered in the age of high fidelity.
During the 1950s home audio was seen as audio on a budget and so the use of the line transformers often used for balanced operation seemed an extravagance, especially when the signal needed to only go a few feet. So home audio became exclusively single-ended operation.
The thing is, during the 1980s high end audio really go going; ARC and others were building monoblock amplifiers and suddenly there was a home application for balanced operation. So at the end of the 1980s we introduced the world’s first balanced line products and that’s how it got started.
The thing is, there’s actually always been a standard for balanced operation! We were aware of it because of my exposure to recording equipment (Steve Tibbetts recorded his second LP in my basement recording studio in the late 1970s). So I knew the standard existed and made sure our gear conformed.
The standard was updated in the 1980s and is now known as AES file 48. Most high end audio equipment with balanced connections does not conform to the standard and as a result does not get all the benefit of balanced operation. That is why there is a conversation about which is better.
The balanced standard is:
1) Pin one is ground
2) the signal occurs between pins 2 and 3
3) ground is ignored by the source and what follows (this is done to avoid ground loops)
4) the balanced source shall have the ability to drive a low impedance; perhaps 1000 ohms or less (600 ohms was the old standard which our gear supports)
items 3 and 4 are the main areas of non-compliance with most high end audio manufacturers.
Please note that balanced and single-ended are inherently incompatible! You can’t be both at the same time- its either one or the other.
In a nutshell, if your gear is competent and conforms to the standard there will be no going back to single-ended. It sounds better even if the cables are only a foot long because there is more to it than just being able to drive long distances. But the first sentence of this paragraph is crafted the way it is because competence is a huge issue. It plays a huge role as well as the ability of balanced lines to eliminate cable artifacts does (which means that a cheap cable and a really expensive one will sound remarkably similar and by that I mean also really good if the balanced standard is used).
Of course, some manufacturers are merely placing the connectors on their gear for convenience while others are really serious about it. So like so many other things in high end audio you just have to audition it and sort it out for yourself. Sorry for so much verbiage on my part for what others have said in a single sentence...
How I see it is I can totally use a 30 foot pair of interconnects in my home (which might cost about $300 for the pair and yet sound as good as a set costing $1000/foot), allowing me to keep the amps right by the speakers with short speaker cables. In this way I minimize the effects of the cables in my system. That is what the balanced standard brings to audiophiles.
In addition, phono cartridges and tape heads are balanced sources. So part of the development of the preamp (the MP-1) was to accept the phono signal in the balanced domain. That in turn eliminates the artifact of the tone arm cable. For those into analog, this is a nice boon.
