Elman BIA Beltpack IFB Amplifier

by Elman
Elman BIA Beltpack IFB Amplifier
The BIA (Beltpack IFB Amplifier), battery-powered belt-pack unit, allows either loudspeaker or headphone monitoring of a communication or audio feed, and is typically used with a presenter's earpiece as part of an IFB kit.

The input gain is controlled by a potentiometer, a 0/20dB gain switch and a selectable limiter. The limiter can be used to ensure a safe listening
level over a wide range of input signal levels and also improves signal intelligibility by preventing clipping of the output signal as the battery
discharges. The balanced output stage of the headphone amplifier drives earpieces and headphone, having either mono or stereo jack plugs,
with connections to the tip and ring only .
Although this cause headphones to driven in anti-phase, intelligibility of speak is unaffected, and the higher impedances of the series
connection ensures the most efficient impedance match to the output stage.

BIA is compatible with similar apparatuses of other brands in commerce.


- Selectable limiter: prevents clipping distortion and damage to hearing with earpieces & headphone types
- Built-in 0.5W loudspeaker & amplifier (power to the amplifier is cut when headphones are connected)
- Loop-through male & female XLR connectors enable several units to be driven from a single feed.
- Headphone output on "A" gauge 6.35mm jack.
- Very low battery consumption.
- Low battery voltage indicator.


-Input impedance: 200K ohm, active balanced
-Input connectors: XLR3 plug & socket
-Input signal limiter threshold (Max Gain): Adjustable
-Battery voltage: 6-9 V
-Gain switch setting 0 dB 20 dB
-Max input level +14 dBU -6 dBU
-Max headphone O/P level (no limiter): +15dBU @ 9V, @ 6V (no load)
-Max headphone O/P level (with limiter): Threshold level +6dB (no load)
-Headphone output impedance: 280 ohm
-Battery voltage for constant limiter output: 9V to 6V
-Maximum Loudspeaker power: 0.5W with 9V battery
-Power supply: 9V PP3 battery (500mAh typical)
-Low battery indicator: threshold 6V

-Dimensions: 120 mm x 78 mm x 43 mmWeight: 250g
-Case: Alluminium Alloy, clear Anodized