It’s possible to build a push-pull amplifier using amplifier ICs, rather than discretes, as in the traditional class B amp (see the figure). A bridged-amplifier configuration effectively doubles the voltage swing at the load. It’s also possible to build a bridge amplifier in which one stage drives one side of the speaker and a second unity-gain inverting amplifier drives the other side of the speaker. However, the configuration in the figure is better, because both amplifiers see the same input signal. This example is borrowed from Maxim Integrated Products’ application note 1122 (www.maxim-ic.com/appnotes.cfm/an_pk/1122).