Pin 1 revisited, adding OEO to an accepted rule

Hans Polak used to strictly adherence to the XLR ‘pin 1’ connection rules in his fully balanced audio system. Yet, when switching on his desktop dimmer-lamp, he still heard strong clicks from his speakers. He decided to get to the bottom of it, starting with the work of Muncy and Whitlock, and came up with the ‘One End Only’ rule that completely cured his desk lamp noise and en passant found a possible reason why mains cables can sound differently.