Balanced Audio Line Driver Off Single Supply
If you are OK with using transformers, a simple audio transformer with a center tapped secondary will convert from unbalanced / single-ended input to 3-wire balanced output, and does not require a bipolar power supply.



simulate this circuit &ndash; Schematic created using CircuitLab
In this circuit, the transformer needs to be able to tolerate whatever DC component may be present in your unbalanced input.
Also, it is assumed in this circuit that whatever is driving the single-ended unbalanced input and the transformer primary have suitably matched impedances. Similarly for the secondary impedance. That is, not just any transformer will do.
You can eliminate the DC component entering the transformer by adding a capacitor.



simulate this circuit
However, you still need to ensure that the transformer's impedance is suitable for the driver.