The higher speed and lower distortion of full balanced signal proceeding is consequently realized in AMP71. From the balanced input through the volume control, the whole power amplifier circuit, up to the speaker terminals the signal is fully differentially proceeded.
Unbalanced input signals will be perfectly balanced by the AMP71.
thus the speaker signal output is balanced as well. This has essential consequences for the whole amplifer. For the same output voltage swing just half power supply voltage is needed.
The same transformer size deliver double current. All power supply capacitors has much more capacitance due to lower voltage.