Precautions for connecting APA outputs to other devices
Multiple audio power amplifiers (APAs) may be connected to one output circuit by design, to multiplex different sources or to connect an external amplifier to save battery life. Also, one amplifier output may be connected to another or to a power supply by mistake. Any of these connections can force APA outputs to abnormal voltages, and this can damage an APA. This article explains limits that must be observed to avoid such damage.