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