Sonifex CM-BHA

Belt Pack Headphone Amplifier with Limiter & Loudspeaker

The CM-BHA can apply gain of up to +20dB to the incoming signal. The volume control simultaneously modifies the output volume and the input gain, allowing input signals in excess of +24dBu to be reproduced without distortion. 

The CM-BHA has an adjustable limiter to protect the listener from excessive levels indicated by a blue LED. The limiter is only enabled when an earpiece or headphones are used, and when it is activated by the toggle switch. It is disabled when no jack is inserted, allowing a higher volume to be passed to the speaker for "squawk mode" use. 

Losing a cue feed due to batteries running out is not an option. With the CM-BHA, a low battery warning LED flashes when the 9V PP3 battery has depleted to 6V, giving plenty of notice to swap the battery. The low power circuitry of the CM-BHA gives up to 200 hours use from a single alkaline 9V PP3 battery. 

Technical Specifications

• Input Impedance: 200kΩ electronically balanced 
• Input Limiter Threshold: Adjustable -14dBu to 0dBu
• Max Input Level: +28dBu
• Input Gain/Volume: Adjustable -70dB to +20dB
• Frequency Response: 20Hz to 20kHz ±0.5 (ref 0dBu 1kHz) 
• Noise: < -75dBu A-weighted (ref 0dB gain) 
• Distortion: < 0.015% (ref +8dBu input, 0dB gain, 10kΩ load)
• Max HP Output Level: +16dBu (ref 9V battery voltage, < 1% THD, 2kΩ load)
  
• Max HP Output Level: +12dBu (ref 6V battery voltage, < 1% THD, 2kΩ load)
  
• Min HP Impedance: 32Ω
  
• Max Speaker Level: +12dBu (ref 9V battery voltage, < 1% THD) 
  
• Max Speaker Level: +6dBU (ref 6V battery voltage, < 1% THD) 
  
• Dimensions: 12.5cm (w) x 6.7cm (D) x 4.8cm (H) 
  
• Weight: Nett: 0.3kg Gross: 0.4kg