Why Single-Ended?
Can somebody give definitions and explain differences between ....First, keep in mind that these terms are often bandied about in a loose manner, and some are inherently ambiguous. So you may frequently see a given term used to mean different things. And there may be legitimate disagreement about some of the following definitions. But FWIW I’ll give it a shot. Single-ended: Either not balanced or not push-pull, depending on context. I have interpreted the OP’s question as referring to "not balanced." Balanced: If referring to a pair of signal lines, the two lines have equal impedances relative to the ground of a circuit, or the two lines are not referenced to a ground. If referring to a pair of signals, the signals have nominally equal amplitudes but opposite polarities. If referring to a circuit or component, the circuit or component processes signals having nominally equal amplitudes but opposite polarities in a symmetrical manner. Truly balanced: Not a technical term, but sometimes used to distinguish between an XLR connector on which a balanced pair of signals is present, and an XLR connector on which just one signal is present. Also sometimes used to mean "fully balanced." Fully balanced: The entire signal path of a component is balanced. Differential: A circuit within a component, or the entire signal path of a component, responds to the difference between two input signals. May also refer to a form of balanced design in which the signal path of a component consists of a series of differential circuit stages. Differential balanced: Usually used in a loose manner to mean "fully balanced." Full differential: Usually used in a loose manner to mean "fully balanced." Truly full balanced: Usually, a somewhat redundant way of saying "fully balanced." Truly full differential balanced: Usually, a somewhat redundant and clumsy way of saying "fully balanced." Regards, -- Al |
What a great post! I have taken quite a bit away from this one, although, I must admit that a lot of it was a little over my head. It is quite refreshing to hear members who have different opinions of design, converse as politely as you all have, regarding your different perspectives. Too many of these threads turn into slanderous name calling, and childish schoolyard bashing. WELL DONE GENTLEMEN !! |
Home audio, especially 2 channel systems with analog being the primary source will rarely benefit from balanced connections. Adding balanced operation in this scenario will only add more circuitry with no real benefit and likely have deleterious effects. One should attempt to have a full-featured preamplifier that includes a well designed phono stage. This approach has significant advantages. The installation is much simpler, the cabling requirements are simpler as this approach has a concentrated purpose. Avoiding ground loops is generally not a problem with this approach and cable lengths can be kept to a very reasonable length. Plus the number of cables is minimized. Balanced topology imposes twice the circuitry into the signal path. Abandoning single-ended connectivity is not an advancement. |
"But the people who are adamant that only one way is technically correct or sounds right are to be ignored. "Surely there is best way for any individual. You and I may not agree on what is best since we may value different virtues, but having on opinion on what I find best does not mean that opinion should be ignored. To the question about single ended versus balanced. Single ended has 2 potentials (voltages). One is fixed commonly called the ground, the return, or the reference level. The outside shield on an RCA plug. The other varies and carries the information (music) which is the center conductor. In balanced you have 2 lines carrying the information so typically 3 pins on the connector. Two for the signals and a third is the ground reference. In an ideal world they are exact opposites with one going positive the exact same amount as the other goes negative. The balanced circuit amplifies the difference between the two so it is differential. One advantage of that is if the cables pick up noise they tend to pick it up equally. The differential amplifier doesn't amplify the noise signals because they are not different. One debate here is if that is important in the home environment. One approach amplifies the difference at the input and another keeps them separate until combined at the output leading to some of the terminology you asked about. Some circuits have a balanced 3 pin input but once inside convert it to single ended or simply don't use one of the signals and are therefore not really balanced or not fully balanced. Beyond that you can have combinations of the 2 like a balanced input followed by some SE amplification converted back to balanced at the output. As Almarg points out, there is no universal agreement on what to call the various configurations so you get a variety of terms which mean different things to different people. Unless you look at the schematic and understand it you are at the mercy of whoever is describing it. https://en.wikipedia.org/wiki/Differential_amplifier |
