The Bosch LBB1925/10 Plena System Pre-Amplifier is a reliable and professional PA system controller designed for paging, background music, and emergency announcements in commercial and institutional installations. It allows smooth control of multiple audio sources across six independent zones, making it ideal for large buildings and multi-area facilities. This pre-amplifier supports microphones with phantom power, multiple BGM inputs, and priority paging, ensuring clear speech and automatic muting of background music during announcements. The built-in speech-optimized tone controls help deliver excellent voice clarity, even in noisy environments. What is the Bosch LBB1925/10 used for? A-1 It is used as a PA system pre-amplifier for paging, background music, and emergency announcements in multi-zone installations. How many zones does this pre-amplifier support? A-2 The Bosch LBB1925/10 supports six independent audio zones. Can I connect microphones and music sources together? A-3 Yes, it supports microphone inputs with phantom power and three BGM line inputs simultaneously. Is it compatible with Bosch Plena amplifiers? A-4 Yes, it is fully compatible with Bosch Plena power amplifiers and call stations. Is this suitable for emergency announcement systems? A-5 Yes, it includes priority muting and emergency/interconnect inputs, making it suitable for emergency PA systems. Specifications Product Type 6-Zone Pre-Amplifier for PA Systems Application Public Address, Paging, Background Music, Emergency Announcements Mains Power Supply 230/115 VAC ±15%, 50/60 Hz Current Inrush 1.5 A / 3 A (depending on voltage) Max Power Consumption ~25 VA Battery Backup 24 V DC, 10% / -15% Max DC Current ~1 A Frequency Response 50 Hz – 20 kHz ( 1/-3 dB) Total Harmonic Distortion (THD) < 0.5 % Channel Separation > 70 dB @ 1 kHz Dynamic Range ~100 dB Priority Mute > 40 dB (automatic BGM muting for paging) Bass Control ± 10 dB @ 100 Hz Treble Control ± 10 dB @ 10 kHz Speech Filter High-pass –3 dB @ 315 Hz, 6 dB/oct Mic/Line Input 1 × balanced (5-pin DIN / 3-pin XLR) with phantom power Sensitivity ~1 mV (mic), ~200 mV (line) Input Impedance > 1 kΩ (mic), > 5 kΩ (line) BGM Line Inputs 3 × RCA (stereo converted to mono) S/N Ratio > 63 dB (mic), > 70 dB (line) Master Output 1 × balanced XLR, ~1 V nominal Tape Output 1 × RCA (2 mono) ~350 mV Headphone Output 6.3 mm jack (mono) ~3 V Zone Relays / Contacts 5 A @ 250 V, 8 A current Emergency / Interconnect Inputs Balanced XLR with adjustable sensitivity Independent Zones 6 zones for BGM and paging Call Station Inputs 2 channels Front Panel Controls Volume, tone, zone selection, priority, source selection Trigger & PC Inputs For automated chimes, alarms, and external control Mounting Standalone or 19″ rack mount (2U height) Dimensions (HxWxD) 100 × 430 × 270 mm Weight ~5 kg Operating Temperature −10 °C to 55 °C Storage Temperature −40 °C to 70 °C Relative Humidity < 95 %
