Williams AV OA-50 Ovation Amplifier/Receiver/Mixer

The Williams AV OA-50 is a classroom-focused receiver/amplifier/mixer that integrates a dual-channel DECT 6.0 wireless mic receiver with a 50-watt (2 × 24.5 W @ 4 Ω) power amplifier. It supports four 3.5 mm audio inputs, conferencing I/O with EchoGuard™ echo prevention, and outputs for assistive listening and lesson capture—providing clear, evenly distributed sound for typical classrooms up to about 2,000 sq ft.

Designed for easy setup and daily use, OA-50 adds practical integrations for school facilities: page mute with pass-through (4 V / 25 V / 70 V systems), fire alarm mute via dry contact, a security alert relay triggered from the teacher mic, and RS-232 control for third-party panels. An anti-hum isolation balun is built into the computer input, and a 5-band EQ plus Digital Feedback Guard help maintain intelligibility.

Key Features

• DECT 6.0 dual-channel mic receiver: 1.92–1.93 GHz, DQPSK, automatic frequency planning (up to 60 talk channels).
• Amplifier: 50 W RMS at 4 Ω (2 × 24.5 W channels); powers up to four 8 Ω classroom speakers.
• Inputs (3.5 mm): rear aux with mic/line switch, rear aux, rear computer (with anti-hum on/off), front “Conference”/aux.
• Outputs (3.5 mm): front Conference out (with level control), rear Assistive Listening System out (with level control).
• Conferencing: EchoGuard™ to prevent far-end audio from returning to the call; front-panel conference I/O.
• Paging integration: page mute + optional page pass-through; supports VOIP/4 V/25 V/70 V systems; 50 mV–12.6 V sensitivity range.
• Fire alarm mute: dry contact input mutes program audio during alarm.
• Security alert: relay interface (N.O./N.C.) triggered from Ovation pendant mic (1- or 4-pulse selectable).
• Control: RS-232 (volume up/down/mute and direct level set), optional OP-10 wall control for power/pairing/standby.
• Signal management: 5-band EQ (±10 dB); Digital Feedback Guard; S/N 70 dB; THD < 0.1% @ 1 kHz.
• Anti-hum: switchable isolation balun on the computer input.
• Power: external 19 VDC / 3.5 A supply; front USB-A 5 VDC/1 A charge output.
• Coverage: approx. 2,000 sq ft wireless connectivity coverage.
• Antenna options: onboard diversity + optional 10 ft magnetic-base extension (ANT-501) for remote mounting.
• Compatible components: OM-10 pendant mic, OM-20 handheld mic, OP-10 panel, SP-628/SP-628L ceiling speakers, SP-2000 wall speakers.

Technical Specifications

• Receiver: DECT 6.0, 1.92–1.93 GHz; modulation DQPSK; automatic interference avoidance; up to 60 talk channels.
• Mic channels: 2 wireless (plus 1 wired via rear aux with mic/line switch).
• Amplifier power: 50 W RMS @ 4 Ω (2 × 24.5 W); frequency response 15 Hz–22 kHz (±3 dB); THD < 0.1% @ 1 kHz; S/N 70 dB; 5-band EQ ±10 dB.
• Inputs: 4 × 3.5 mm (rear aux [mic/line], rear aux, rear computer with anti-hum on/off, front conference/aux).
• Outputs: 3.5 mm Conference out (front, level control); 3.5 mm ALS out (rear, level control).
• Paging: 2-pin Phoenix input, nominal 4 V / 25 V / 70 V; sensitivity 50 mV–12.6 V; pass-through selectable.
• Fire alarm: dry contact closure input (mutes sources; resumes ~11 s after closure ends).
• Security alert: relay interface (COM/N.O./N.C.), 1- or 4-pulse selectable.
• RS-232: 3-wire TX/GND/RX; front-panel input knobs disabled when RS-232 switch ON.
• USB charge: 5 VDC / 1 A (USB-A).
• Power supply: 19 VDC / 3.5 A (CE, CSA, UL listed).
• Dimensions: see above (8.5" × 7.5" × 1.75" or 7.5" × 8.5" × 1.75", orientation not specified).
• Weight: 1.75 lb (0.794 kg).

What's Included

• 1x Ovation™ Amplifier with integrated mixer base station
• 2x DECT wireless receivers (built-in)