The AM 501 is a high-power operational amplifier unit designed for use in the TM 500 series power modules. The unit has a wide output voltage swing centered at zero, high common-mode range, and a high slewing rate. The AM 501 has convenient front-panel access terminals for connection of feedback resistors to either input, or various input loading configurations. Internal pads on the circuit board permit permanent loading, feedback, or input component connections. A front-panel switch permits selective grounding of either bnc input or binding post connectors. The output may be taken from front-panel binding posts or a bnc connector.