Bosch LBB 1925 Plena System Pre-Amplifier

(4 customer reviews)
BOSCH

The Bosch LBB 1925 Plena System Pre-Amplifier is a versatile 6-zone controller for public address installations, supporting simultaneous paging and background music. With universal mic/line inputs, selectable BGM sources, tone control, and direct zone routing, it enables cost-efficient and professional multi-zone audio management

63,418.00 Excluding Tax

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The Bosch LBB 1925 Plena System Pre-Amplifier is a high-performance audio control unit designed for professional public address systems across commercial, corporate, hospitality, and institutional environments. It supports dual-channel operation, allowing simultaneous paging and background music (BGM) in up to six independent zones, making it ideal for buildings requiring flexible audio distribution.

Flexible Paging & Announcement Control

Bosch LBB 1925 Plena System Pre-Amplifier call channel includes two call station inputs compatible with the Bosch LBB 1941/00 (all-call) and LBB 1946/00 (6-zone) call stations, complete with loop-through capabilities. Users can connect via 3-pin balanced XLR for mic/line sources or a 5-pin DIN with priority contacts, enabling the activation of chime tones for attention-grabbing announcements.

Speech clarity is enhanced with a switchable speech filter, volume control, and dedicated bass/treble tone controls optimized for vocal performance. All call announcements are routed to the balanced XLR master output, ensuring clean signal delivery to connected amplifiers.

Music Distribution & Zone Selection

The BGM channel offers three stereo input options (RCA), internally converted to mono, with front-panel input selection for easy source switching. This audio path also includes music-optimized tone control to ensure pleasant background sound across all zones.

Zone routing is incredibly simple thanks to individual zone selector switches located on the front panel, enabling music and paging to be directed precisely where needed — whether across all zones or selected areas.

Bosch LBB 1925 Plena System Pre-Amplifier Installation Smart Features

  • 24V DC overload-protected output simplifies installation by powering external relay modules

  • Ideal for schools, malls, transport hubs, hospitality venues, office buildings, and more

  • Works seamlessly with Bosch Plena amplifiers for scalable, cost-efficient system design

With its powerful feature set, reliability, and attractive affordability, the Bosch LBB 1925 Plena System Pre-Amplifier delivers the perfect balance of professional audio control and multi-zone flexibility for any modern PA installation.


🔸 Bosch LBB 1925 Plena System Pre-Amplifier Key Features

  • 6-zone pre-amplifier with single or dual-channel operation

  • Two call station inputs with priority & chime activation

  • Universal mic/line input with speech-optimized tone control

  • Three BGM inputs with music-optimized tone control

  • Front-panel zone selection for paging & BGM routing

  • Overload-protected 24V DC auxiliary output for relay powering

  • Balanced XLR outputs for master and direct BGM channels

  • Cost-effective solution for multi-zone PA systems

LBB 1925/10

Brand

Technical specifications

Mains power supply
Voltage 230/115VAC, ±15%, 50/60 Hz
Current inrush 230/115 VAC, 1.5/3 A
Max power consumption 25 VA
Battery power supply
Voltage 24 VDC, +10% / -15%
Current max 1 A
Performance
Frequency response 50 Hz to 20 kHz (+1 / -3 dB)
Distortion <0.5%
Bass control ±10 dB @ 100 Hz
Treble control ±10 dB @ 10 kHz
Channel separation >70 dB @ 1 kHz
Priority mute >40 dB
Dynamic range 100 dB
Mic/line input 1 x
Connectors 5‑pin DIN, 3‑pin XLR, balanced, with phantom power
Sensitivity 1 mV (mic), 200 mV (line)
Impedance >1 kohm (mic); >5 kohm (line)
S/N (flat at max volume) >63 dB (mic); >70 dB (line)
S/N (flat at min volme/muted) >75 dB
CMRR >40 dB (50 Hz – 20 kHz)
Headroom >25 dB
Speech filter -3 dB @ 315 Hz, high-pass,

6 dB/oct

Phantom power supply 16 V via 1.2 kohm, (mic mode only)
Line input 3 x
Connector Cinch, stereo converted to mono, unbalanced
Sensitivity 200 mV
Impedance 22 kohm
S/N (flat at max volume) >70 dB
S/N (flat at min volume/ muted) >75 dB
Headroom >25 dB
Master output 1 x
Connector 3-pin XLR, balanced
Nominal level 1 V
Impedance <100 ohm
Tape output 1 x
Connector Cinch, 2 x mono
Nominal level 350 mV
Impedance <1 kohm
Headphone output 1 x
Connector 6.3 mm jack stereo, signal mono
Nominal level 3 V
Impedance <100 ohm
Zone relays 5 A
Contacts voltage 250 V
Contacts current 8 A
Interconnection input / emergency 1 x
Connector 3-pin XLR, balanced
Sensitivity 200 mV (interconnection),

100 mV to 1 V adjustable (emergency)

Impedance >10 kohm
VOX threshold 45 mV (emergency)
Interconnection output 1 x
Connector 3-pin XLR, balanced
Nominal level 200 mV
Impedance <100 ohm
Relay contacts 30 V, 1 A
DC supply output voltage 24 V, 250 mA max
Dimensions (H x W x D) 100 x 430 x 270 mm (19″ wide, 2U high)
Weight Approx. 5 kg
Mounting Standalone, 19″ rack
Color Charcoal

Based on 4 reviews

4.5 overall
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  1. Gomathi

    I am using forthe past 8 months Plena Amplifier . Elegant design and very good build quality. Sakthi Av Tronics service was very satisfactory an all the staffs
    were very polite.

    Gomathi

  2. Durga Devi

    Awesome product purchased from Sakthi AV Troncis Bosch Plena Amplifier . I am using for many months. No issues and the price was also affortable.

    Durga Devi

  3. Ananthu

    LBB 1925/10 Plena System Pre-Amplifier is very Good. I didn’t except the quality of the product.
    I got lowest price from Sakthi AV Tronics

    Ananthu

  4. Krishna Prasad

    Bosch Plena System Pre-Amplifier
    Quality is Awesome. Got very Lowest Price from Sakthi AV Tronics.

    Krishna Prasad

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