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