All input and outputs are electronically balanced.
The external side chain inputs are unbalanced. Tip = signal, ring & sleeve = cable shield/ground.
All our rack units are switchable between 115v or 230v with a voltage selector switch inside the unit. Remember to change the fuse as well! 115v = 200mA slow blow, 230v = 100mA slow blow.
Yes you can, both units can handle line levels signals, just use the pad switch if needed.
Yes you can use it for mono sources but only for one source at a time as the timing circuits are common for left and right channel.