Cmad Engineering Solution

The LBD1938/00 amplifier is a powerful power amplifier in a 3U housing 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.The LBD1938/00 amplifier features a colorful LED bar on the front side to indicate the acoustic level of the signal in dB. The LBD1938/00 amplifier has a 100 V input for slave operation of the amplifier, XLR loop in and loop through facility for ease of installation and a 100 V output as well as 70 V output for connecting to the loudspeakers with line matching transformers, 8 ohm and 4 ohm outputs for connecting to the Low impedance speakers. The output voltage can be selected between 100 V and 70 V internally. The 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 24 VDC power supply during emergency situations.

The portable mixer amplifier is a professional public address unit with modern state‑of‑the‑art features, which is built on class-D platform. The amplifier is easy to use, taking the complexity away from the user and putting it where it belongs, inside the equipment. Providing a crisp call or clear music is as easy as turning on a radio. Offering the essentials of public address in an affordable package.The portable mixer amplifier is designed to meet the requirements of the people who are on the go. It has an inbuilt music player which can support audio streaming through Bluetooth or USB/TF card and also supports FM. An IR remote control is supplied with the unit to control the music source. The amplifier can be powered either with a 12/24V battery source or via a power adapter, which is supplied with the unit. It is equipped with two microphone inputs, microphone input-2 comes with a phantom power supply option. It also has an AUX input option for connecting external audio sources. It also supports ducking, by which the background music automatically fades away when there is a live announcement from any of the microphone inputs and is automatically restored after the announcement, avoiding the human/manual intervention of the operator. The ducking option is variable and it can be switched off based on the user requirements. The processor in the amplifier monitors the speaker output line. In case there is a short circuit or overload in the speaker output line, the amplifier isolates the amplification circuit and enters into selfprotection mode and the user is informed with a fault indication. The amplifier also monitors the battery status. If the connected battery output goes low, the amplifier will detect this and the user will be informed with a battery low indication: If the battery output goes below the threshold value, the amplifier will isolate the output and protect the battery from draining any further. The rear of the amplifier is equipped with a replaceable DC fuse for further protection.

The Plena system pre-amplifier is a versatile, highperformance unit with call and mono BGM (background music). It fulfills a wide variety of public address requirements at a surprisingly low cost. It can provide dual channel operation for simultaneous calls and BGM for up to six different zones, using two Plena amplifiers. The call channel provides two inputs for the Plena call stations, LBB 1941/00 (all-call) or LBB 1946/00 (sixzone), with loop-through capability, and universal, balanced input. One is a 3-pin XLR connector for microphone or line level (selectable), and the other is a 5-pin DIN-connector with all‑call priority contact, which may also be used to start one of the available chime attention signals. The microphone input has a selectable speech filter for improved intelligibility, a volume control, and bass and treble tone controls with shelving characteristics optimized for speech. The call channel is available on the balanced XLR master output.