Williams AV IMA-840 Spectrum Receiver Amplifier, Amp Only
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Williams AV Spectrum Receiver Amplifier, Amp Only
The Spectrum™ Receiver Amplifier in the “Amp Only” configuration provides a powerful, versatile solution for large-room audio reinforcement without bundled microphones or speakers. Designed for spaces exceeding 1,600 sq ft, it includes infrared receivers, multiple input/output options, and robust integration with paging, security, and assistive listening systems.
This amplifier features four 25 W digital Class‑D channels (100 W total), 5‑band digital equalization, and support for dual infrared microphone reception. It offers programmable security alert inputs, fire alarm mute functionality, line-level integration for media and conferencing, and energy-saving standby mode. A 5 V USB port enables charging of Williams AV microphones.
Key Features
- Amplifier Power: Four channels @ 25 W RMS each (100 W total)
- Receiver Input: Infrared FM supporting two wireless microphones
- Coverage: Up to 1,600 sq ft per IR sensor, supports two sensors
- Line Inputs: 4 total (1 dual RCA + 3 × 3.5 mm) including anti‑hum balun for computer input; one auxiliary input is mic‑selectable
- Line Outputs: 3.5 mm Conference (front panel) and Assistive Listening System (rear), both with gain control
- Paging Integration: 2‑pin Phoenix page input selectable for 4V, 25V, or 70V systems with sensitivity control
- Alert/Alarm Functions: Security alert (contact closure), fire alarm mute (audio mutes during alarm)
- Equalization: 5‑band, ±12 dB digital EQ
- Power Save: Low‑power standby mode
- USB Charger: 5 V DC output for charging microphones
Technical Specifications
- Dimensions: 8.5″ × 1.75″ × 7.5″ (21.6 cm × 4.4 cm × 19.1 cm)
- Weight: 2 lb 6 oz (≈ 1.1 kg)
- Amplifier Output Power: 4 × 25 W RMS, 100 W total
- Receiver Input: Infrared FM, 2 wireless mic channels
- Modulation & Frequencies: Wide-band FM; Ch A: 2.08 MHz, Ch B: 2.54 MHz; deviation ±10 kHz nominal (±25 kHz max); tone key: 32.768 kHz; de-emphasis: 50 μs
- Frequency Response: 20 Hz–20 kHz, ±3 dB
- THD: <1% @ 1 kHz
- S/N Ratio: > 65 dB
- Sensor Input: 2 × RCA, powered; coverage 1,600 sq ft per sensor
- Line Inputs: 1 dual RCA + 3 × 3.5 mm; anti‑hum balun on computer input; one aux input switchable to mic
- Line Outputs: Front – Conference (3.5 mm w/ gain); Rear – ALS output (3.5 mm w/ gain)
- Page Input: Phoenix 2‑pin (4 V/25 V/70 V); sensitivity adjustable
- Security Alert: Contact closure (COM, N/O, N/C)
- Fire Alarm Input: Mutes audio via contact closure
- Equalizer: 5‑band ±12 dB
- Charger Output: 5 V DC USB
- Power Supply: 19 V DC / 6.3 A, CE/CSA/UL listed
What's Included
- 1x Receiver Amplifier unit (Amp Only) – no microphones or speakers included
