Originally Posted by highrolller
I don't understand what balanced headphones and amps are... Is it just like any other headphone and amp with a different sound and exit plug?
in terms of what they provide, a balanced setup gives you noise rejection and more immunity to interference, as well as doubling the power output
more technically (at least this is how i understand it):
a normal setup, or single ended setup, has one signal wire per channel (the + signal), and one ground (shared by both channels). look at any stereo (no in-wire mic) 1/4" or 3.5mm plug and you should see two bands of insulator rings, creating 3 metal conductor parts, those 3 metals each carry the left +, right +, and shared ground signals. the power differential (and how sound is made by the diaphragms) is from the + signal and the ground (consider this 0).
a balanced setup has two signal wires per channel, the + signal (same as in single ended), and the - signal, which is the exact reverse (in terms of polarity) as the + signal. so the simplest balanced cable (e.g. 4-pin XLR) has 4 connector heads, each carrying the left +, left -, right +, and right - signals. no ground is technically needed because the power differential is from the + signal and the - signal (which is also why the power output is doubled)
how this gives you noise rejection: say you send a signal of +10 through two setups, one single ended (where the correct signal to receive should be 10) one balanced (where the correct signal to receive should be 20, double the original signal), and some interference/noise is present in transmission, which lowers your signal by 2. on single ended setups, your + signal becomes 8 due to noise, and the power differential to ground therefore becomes 8 (ground is always 0), which is not the same as your original signal. on the balanced setup, because the + and - signals are in two wires twisted together, you can assume that the noise affects both signals equally. you send half of the original signal from each of the + and - wires, and due to the noise the + signal becomes 8 (10 - 2) due to noise, and the - signal becomes -12 (-10 - 2). the differential in the end is 20 (8 - -12), which is what your original signal was.