I've had a B32S for over a year now running Single Ended RCAs to amp OR to HP amp (replugging when needed.
I've just finished installing balanced XLRs & converted my Sennheiser HD540s to balanced.
Sounds very nice. Haven't yet swapped back to stock SE cables to compare balanced to SE performance, but:
Read in B32S manual that "The PCB has 4 marks near the outputs which when cut make the output impedance 21Ω. People using the DAC to drive headphones may wish to leave those uncut. Those using the DAC into capacitive cables and/or an amplifier will want to cut those traces where marked with red circles on figure 1. You will see the parallel lines on the PCB silkscreen that indicate where to make your cut.".
I cut the 4 tracks to use with the RCAs and my amp.
My HD540s are 600Ohm, & I can measure the balanced cables' capacitance & inductance (but haven't yet).

Question is, should I bother installing a 4-pole switch to the 4 cut tracks to join them back up for HP use, or not bother?
What is the output impedance with the tracks not cut?
If I need to solder the switch into the circuit either side of the cuts, where's the best place (I don't want to cook the SMD opamps).
If I don't bother to rejoin tracks, what effect should it have on the sound through the headphones (less bass, less treble, more distortion)?

Thanks Wackyterbacky,
Found answer:
Use through-holes on output side of R47-R50.
Sounds great.

Now I don't need the separate (unbalanced-input) HP amp I was using.