Power Amplifiers

A power amplifier takes a finished line-level signal and drives the speakers, while a mixer amplifier adds its own microphone and source inputs with level controls. The Citronic QP Series amplifiers such as the 172.241UK have balanced line inputs and parallel outputs for daisy-chaining, and the TOA P-2240 is a booster that takes the 100V output of an A-2000 series mixer-amplifier.

Match the amplifier output at the speakers’ impedance to what the speakers can handle. Citronic lists the PLX 172.214UK at 2 x 1000W RMS into 2 Ohms, stable down to 2 Ohms per side and bridgeable to mono at 4 Ohms. Add up the speaker tap wattages on a 100V line and keep the total within the amplifier rating.

Bridge mode combines two amplifier channels into one mono output with more power. The Citronic D-Series amplifiers such as the 172.103UK have switchable parallel and bridge modes, the Penton DPA4125 supports bridging two channels to double the power, and LEA Professional Smart Power Bridge on models such as the CS702 bridges a channel for double the power.

A 100V line amplifier drives a high-impedance speaker line, the usual design for background music, paging and voice alarm across many ceiling or wall speakers. The Penton DPAFOUR125 is transformer isolated for 100V, 70V, 50V and 4 Ohm systems, the TOA VM-2240 feeds five high-impedance zones, and the Vanco PAV140 gives 40W on 70 or 100 volt systems.

Class-D is the lightweight, high-efficiency design, while Citronic builds its hybrid Class-H models for high sound pressure levels in medium to large systems. The Citronic D-Series 172.110UK uses Class-D circuitry in a lightweight 1U case, and the Penton DPA4125 quotes 90% amplification efficiency. The Citronic 172.125UK combines a digitally controlled power section with a class-H output stage for high sound pressure levels.

Use an amplifier built for the voice alarm system you are installing. The Penton DPAFOUR125 is a voice alarm amplifier, the Signet ABT-PA8160B amplifies and distributes audio from the VACIE system control unit, and the TOA VM-2240 supports emergency broadcast. Penton BPA amplifiers such as the BPA-2240 are fully fault monitored for early warning of failure.

An induction loop amplifier drives a hearing loop so that hearing aids set to the T switch pick up clear sound. The Adastra LA-300 MK2 and LA-600 MK2 are LA Series loop amplifiers, and Adastra fits the LA-600 MK2 with mic/line level and phantom power switches for each input and tamper-proof controls for volume.

Yes, several amplifiers here mount in a wall. The Vanco PA230BWA is a single-gang in-wall Bluetooth receiver with a 2x30W amplifier for 4 Ohm or 8 ohm speakers, the Vanco PA230SWA streams over Wi-Fi, the Adastra IWA415B gives 4 x 15W with Bluetooth, and the Adastra WA-215 wall amplifier has a 57mm back box, USB/microSD playback and an FM tuner.

Yes, with an amplifier that has a sub output and crossover. The Citronic 172.248UK P Series is a 2.1 channel amplifier rated 2 x 400W + 800W, with two channels for mid-top cabinets and a single high power sub output with an integral active crossover of variable frequency. The Citronic 172.132UK Hybrid Class-H has a switchable 120Hz low-pass crossover, useful when one channel feeds a subwoofer.