Sonifex CM-BH4W Belt-Pack 4-Wire Headphone Amp

The CM-BH4W is a portable, battery powered 4 wire communication unit for use in a multitude of TV and radio broadcasting applications. The CM-BH4W uses audio transformers at its input and output, providing galvanic isolation from outside interference, ensuring your communications are loud and clear, every time. In 4-wire mode, the unit acts as a 2-way intercom, with input audio routed to the headset earpiece, and microphone audio is routed to the output upon pressing the talk button. The output level is maintained at +2dBu peak level by a built-in AGC. In IFB mode, the input audio is routed to the output, and is interrupted by the microphone signal when the talk switch is pressed. The talk switch can easily be converted from momentary to latching operation to suit your application.

Technical Specifications

Mic In to Line Out
Mic Input Impedance
1k5ohms Unbalanced for 200 dynamic microphone
Limiter Input Threshold
-60dBu
Line Output Level
+2dBu
Line Output Impedance
150ohms Transformer balanced
Line In to Headphone Out
Line Input Impedance
>10kohms Transformer balanced
Input Gain/Volume
Adjustable off to +10dB
Maximum Input Level
+24dBu
Maximum HP Output Level
+7dBu (ref 9V battery voltage, <1% THD, 100ohms load)
Minimum HP Impedance
100ohms
Connections
Line Input
1 x XLR 3 pin female socket (balanced)
Line Output
1 x XLR 3 pin male plug (balanced)
Headset (CM-BH4W)
1 x ” (6.35mm) mono unbalanced jack socket
Headset (CM-BH4WX)
1 x XLR 4 pin male plug (balanced)
Equipment Type
CM-BH4W
Belt-pack 4-wire headphone amplifier
CM-BH4WX
Belt-pack 4-wire headphone amplifier with 4 pin XLR headset connector
Physical
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: 0.6lbs Gross: 1.0lbs