Thursday, April 02, 2009

Single-ended vs. Balanced

There never seems to be a shortage of questions about the difference between single ended and balanced connections when it comes to high-end audio. This will be a bit of a simplification but in a single ended connection (normally utilizing an RCA connector) there is a "signal" (the music) and a "ground" (electrical ground.) In a balanced connection (normally carried on and XLR but sometimes on other connectors for PRO applications) there is the "signal" (again music) the "ground" (electrical ground) then the third leg is "the signal 180 degrees out of phase." That is to say AN EXACT OPPOSITE of the original musical signal.

The practical benefit is that if the entire system is balanced, including inside the components at the end of the chain the "signal" and the "inverse of the signal" can be compared. Anything that they have in common must be noise picked up in the journey of the signal, and is therefore discarded. Making for "blacker" backgrounds and wider, deeper sound stages.*

It is important to note that just because a component has XLR connectors on the back DOES NOT mean that the circuit is truly balanced. Many time manufacturers will add XLR connects for comparability with other gear OR as marketing hype. A truly balance circuit close to doubles the price of a component because for every wire, cap, resistor, etc there must now be two. Only the chassis and the power supply don't need to be doubled. If it isn't balanced throughout the entire circuit, it's of negligible value. In fact, a pseudo-balanced design adds one EXTRA part in the signal path that wouldn't be in the signal path for the single-ended connections which is usually phase splitter used to "manufacturer" a balanced signal when only a single-ended one exists.

*Not everyone agrees that balanced connections run over shot distances have an audible effect, including some very good manufacturers. Like many things in high-end audio there are some very knowledgeable honest people on both sides of the fence. For the record my system is balanced, but I've heard many impressive systems that were purely single-ended.

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