Creating A Balanced Line Output
From an unbalanced line level signal
Converting Balanced Line Level to Un-Balanced
NOTE: The 22K resistors used here work great, but 22K can cause noise to be picked up from close digital tracks (e.g. 3.3V clock signals). We discovered just such a problem on a digital PCB causing pickup to occur at the negative op amp input and the remedy was to change to 2K resistors instead.