The LBD193x amplifiers feature colorful LED bar on the front side to indicate the acoustic level of the signal in dB.LBD193x amplifiers have 100V input for slave operation of the amplifier, XLR loop in and loop through facility for ease of installation and 100V output as well as 70V output for connecting to the loudspeakers with line matching transformers, 8ohm and 4ohm outputs for connecting to the Low impedance speakers. The output voltage can be selected between 100V and 70V internally. Additionally LBD1938/00 amplifier features a dual XLR inputs with priority switching. Gain or level control is located on the rear of the unit to avoid accidental setting change. The amplifier works on 24VDC power supply during emergency situations.