The CM-BHA is a battery-powered portable headphone amplifier designed for live applications such as field reporting.

Wide signal range capability

The CM-BHA can apply up to +20dB gain to the incoming signal. The volume control simultaneously adjusts output volume and input gain, allowing distortion-free reproduction of input signals above +24dBu.

Adjustable limiter to protect listeners

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

Low battery warning

Losing a foldback signal due to exhausted batteries is not an option. With the CM-BHA, a low battery warning LED flashes when the 9V PP3 battery has fallen to 6V, giving ample time to change the battery. The CM-BHA's low current circuit provides up to 200 hours of use from a single 9V PP3 alkaline battery.

CM-BHA Technical Specifications

Input Impedance:
200kΩ, electronically balanced

Input Limiter Threshold:
Adjustable from -14dBu to 0dBu

Maximum Input Level:
+28dBu

Input Gain/Volume:
Adjustable from -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 Headphone Output Level:
+16dBu (ref 9V battery voltage, <1% THD, 2kΩ load)
+12dBu (ref 6V battery voltage, <1% THD, 2kΩ load)

Minimum Headphone Impedance:
32Ω

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

Equipment Type

CM-BHA
Portable headphone amplifier with limiter and speaker

Physical Specifications

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 (packed):
23cm (W) x 13cm (D) x 8cm (H)
9.1" (W) x 5.1" (D) x 3.1" (H)

Weight:

Net: 0.3kg
Gross: 0.4kg

Net: 0.7lbs
Gross: 0.9lbs