balanced to unbalanced audio switch
Balanced uses XLR connectors and unbalanced uses RCA connectors, they also use different cables, so I wonder what the switch's purpose would be. It makes no sense to switch a balanced signal to a RCA, or an unbalanced signal to a XLR.


  if you want unbalanced audio from this set up, you would just take the audio from pins 1 and 2, and dont connect pin 3. This gives you an unbalanced audio output.


Correct.

Note "balanced" does not mean two signals of opposite polarities. It means that both signals in the differential pair have the same source impedance, which gives best common mode rejection at the receiver. If both signals (hot/cold) have opposite polarity, headroom and SNR are maximum. But if you just use one hot signal and set the other (cold) to 0V, you still get to keep all the advantages of balanced connection with regards to EMI/noise rejection, only sacrificing a bit of headroom which never was required in the first place since the unbalanced signal source levels are at line level, thus lower that what is specified for XLR balanced...

So, to convert a signal from unbalanced to balanced, connect:


Source signal to Balanced Hot
Source ground to Balanced Cold at the source


You don't actually need opamps.