This is the output stage of the CTAG : it has 300 ohm resistor and 47 microfarad capacitor in series.
Impedance balancing can be obtained by using that as the balanced+(hot) signal and adding an equivalent impedance to ground to the balanced-(cold) signal. This requires three passive components per channel (in addition to the connector). In the diagram below "CTAG OUT" is the existing ctag output pin. The components in the box are those that need to be added