Sonifex CM-BHA - Belt Pack Headphone Amplifier

The CM-BHA is a portable, battery powered headphone amplifier for use in live applications such as in-the-field news reports.

Wide Signal Range Capability

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.

Adjustable Limiter Protects Listeners

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..

Low Battery Warning

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 Specification For CM-BHA

Input Impedance:
200kΩ electronically balanced

Input Limiter Threshold:
Adjustable -14dBu to 0dBu

Maximum Input Level:
+28dBu

Input Gain/Volume:
Adjustable -70dB to +20dB

Frequency Response:
20Hz – 20kHz ±0.5 (ref 0dBu 1kHz)

Noise:
<-75dBu A-weighted (ref 0dB gain)

Distortion:
<0.015% (ref +8dBu input, 0dB gain,10kΩ load)

Maximum HP Output Level:
+16dBu (ref 9V battery voltage, <1% THD, 2kΩ load)
+12dBu (ref 6V battery voltage, <1% THD , 2kΩ load)

Minimum HP Impedance:
32Ω

Maximum Speaker Level:
+12dBu (ref 9V battery voltage, <1% THD)
+6dBu (ref 6V battery voltage, <1% THD)

Equipment Type

CM-BHA
Belt Pack Headphone Amplifier with Limiter & Loudspeaker

Physical Specification

Dimensions (Raw):
12.5cm (W) x 6.7cm (D) x 4.8cm (H)
4.9” (W) x 2.6” (D) x 1.9” (H)

Dimensions (Boxed):
23cm (W) x 13cm (D) x 8cm (H)
9.1 ” (W) x 5.1” (D) x 3.1” (H)

Weight:

Nett: 0.3kg 
Gross: 0.4kg

Nett: 0.7lbs 
Gross: 0.9lbs