|
The first audio manufacturer to employ XLR connectors was Ampex. As what I understand was literally a case of "just pick one," they decided to wire the connectors with pin 3 as the high side of the balanced connector.
Meanwhile an international standard was developed during the late 1950s that called for pin 2 of any electrical connector to be the high side. At the time most manufacturers outside the U.S. weren't using XLR connectors but when they entered the American market many wired their gear with pin 2 hot. Sony chose to be compatible with Ampex because they knew all of the big American broadcasters wired their facilities pin 3 hot and rewired anything that was shipped pin 2 hot because they weren't about to rewire everything in their company just to match an international standard.
The microphone industry was only just introducing the use of XLR connectors in the late '50s and they decided to ship their products with pin 2 positive for positive air pressure. Some U.S. studios and broadcasters simply rewired the mikes to pin 3 hot.
The result of all this in the U.S. was random polarity everywhere depending on where and how balanced connections became unbalanced. If you recorded a pin 2 hot mike with an Ampex, it played back pin 2 hot on the Ampex. If you played the tape on a Studer, the polarity flipped.
An amazing can of worms...
|