Bosch LBD1938/00 Amplifiers

Bosch LBD1938/00 Amplifiers

39,015.00 Price excluding tax




  • Wide range of power amplifier from 120W, 240W and 480W.
  • Multiple outputs – 70 V / 100 V and 8/4 ohm.
  • Temperature controlled forced front to back
    ventilation, directly stackable.
  • Mains, battery back-up, and pilot tone supervision.

BOSCH LBD1938/00 480W Plena Booster Amplifier are powerful power amplifier in a 2U high 19”case (3U housing for LBD 1938) for rack mounting or tabletop use. The Bosch Plena power amplifier series with its varied amplification range fulfills a wide variety of public address requirements at a surprisingly low cost.

System overview
BOSCH LBD1938/00 480W Plena Booster Amplifier feature colorful LED bar on the front side to indicate the acoustic level of the signal in dB.LBD1938 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

The amplifier is protected against overload and short circuits. A temperature-controlled fan ensures high reliability at high output levels and low acoustic noise at lower output levels. An overheat protection circuit switches off the power stage, if the internal temperature reaches a critical limit due to poor ventilation or overload.

The system has two balanced inputs with priority control, each with a loop-through facility. This makes it easy to connect remote systems that require priority control. An additional 100V line input is provided to connect the amplifier to a 100V loudspeaker line to provide more power to remote locations. Gain or level control is located on the rear of the unit to avoid accidental setting change. A meter with LED-bar shows the output level.

The amplifier has 70V and 100V outputs for constant voltage loudspeaker systems, and a low impedance output for 8 ohm or 4 ohm loudspeaker loads. LBD1938 amplifier also has priority controlled 100V outputs which can be used to route audio coming into priority and program inputs to the loudspeaker. The LBD1938/00 amplifier has priority input and program input on the rear which can be used for routing important or emergency announcements when the amplifier is being used as a independent amplifier(ex: with local music source connected to program input). There are Priority input enable and Program input enable pins which are default off and default on respectively, when these enabled by a 24VDC signal then the respective inputs are activated. Whenever the priority enable input is supplied with continuous 24VDC signal, the program input is over-ridded by the priority input. Certifications and approval

Technical specifications


Power supply
Input Voltage 230VAC ±10% at 50/60Hz or 24VDC
Inrush Current 19A at 230 VAC, 30A at 24 VDC
Rated Output (RMS) 480W
Power reduction on backup power -1 dB
Frequency response 60 Hz to 18 kHz (+1 / -3 dB at -10 dB ref. rated output)
Distortion <1% at rated output, 1 kHz
S/N (flat at max volume) > 90 dB
Power consumption
Max power consumption 1600 VA
Mains operation
Max power 990W
-3 dB 715W
Pilot tone 110W
Idle 25W
24V DC operation
Max power 32A (770W)
-3 dB 26A (625W)
Pilot tone 3.8A (91W)
Idle 0.7A (17W)
Line Input s 2 x
Connector 3-pin XLR, balanced
Sensitivity 1 V
Impedance >20k ohm
CMRR >25 dB (50 Hz to 20 kHz)
Gain 40 dB
100 V input
Connector Screw, unbalanced
Sensitivity 100 V
Impedance 330k ohm
Line l oop through output 2 x
Connector 3-pin XLR
Nominal level 1V
Impedance Direct connection to line input
Loudspeakers outputs 3 x
Connector Screw, floating
Direct output 100 V, 70 V, 8/4 ohm
Priority only (from input 1) 100V/70V internally selectable
Music (non-priority) only 100V/70V internally selectable
Dimensions (H x W x D) 145 x 430 x 370 mm
Weight 25 kg
Color Charcoal
Mounting 19″ rack, 3U height
Operating temperature -10 ºC to +45 ºC
Storage temperature -40 ºC to +70 ºC
Relative humidity <95%
Acoustic noise level of fan <48dB SPL at 1m(max output)


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