While we're on the subject of balanced connections for analog audio signals, I've occasionally wondered why phonograph pickups never made use of balanced connections. Most moving magnet pickups produce signals of abut 5 mV, similar to that of microphones. It seems like that low signal level would benefit if it made use of a balanced connection.
I understand that the connection between a pickup and the phono pre-amp is not balanced because of their impedance differences. Is there something about a phonograph pickup, or a phono pre-amp, that makes it impractical to alter their output or input impedance to allow a balanced connection? Or, was this an extra complication that the audio industry never thought necessary during the 1950s or 60s?
And finally, if balanced connections were never used for low level signals from phonograph pickups, why do audiophools now rush to use them between analog sound sources, pre-amps, and external amplifiers? All of them involve signal voltages much higher than 5 mV. It does seem like balanced audio connections in home audio is a solution looking for a problem. XLR plugs make for better looking audio jewelry than RCA plugs.