The 0/2/4 is a voltage preamplifier with switch-selectable gain ranges of 0, 20, and 40 decibels. The 0/2/4, along with the 2/4/6, represent Physical Acoustics’ premium series of general purpose preamplifiers, meant for laboratory use when the gain or frequency bandwidth needed for the application is not known in advance. The 2/4/6 preamplifier is designed to be used with all AE systems that have their power supplied via the output signal BNC. It operates with either a single-ended or differential sensors. Plug-in filters provide the flexibility to optimize sensor selectivity and noise rejection. These filters are supplied in the Lows Pass (LP), High Pass (HP), and Band Pass (BP) configurations, and offer constant insertion loss for easy filter swapping without the need for recalibration. Auto Sensor Test (AST) allows the sensor to characterize its own condition, as well as send out a simulated acoustic emission wave that other sensors can detect.