Battery Box BB2

Description

The BB2 powers stereo electret microphone capsules with 8.3V plug-in power so you can use them with any stereo microphone input. The BB2 should work with any stereo electret microphone that can be powered by plug-in power, including the low noise Primo EM272 capsules and Clippy EM272 mics.
The stereo minijack output can connect to any device with a stereo minijack microphone input using a stereo minijack cable (not included).
The switchable high-pass filter removes unwanted low frequency content. The filter is designed to be subtle and not change the overall sound quality of the microphone.
The battery box is powered by a 9V PP3 battery, and can be turned off by unplugging the input.
To replace the battery, unscrew the lid to gain access to the battery clip (the screws are located on the underside of the device). When replacing the lid, be careful not to trap the battery clip cable and do not over-tighten the screws. The battery should last a long time and will not need to be replaced often.

Specifications

Powering:
    •    9V PP3 battery
    •    8.3V plug-in power via 6k8 Ohm resistors
    •    battery life approx 11.5 days with new Alkaline battery and two EM272 capsules

Connections:
    •    3.5mm stereo minijack input for microphone
    •    3.5mm stereo minijack output to recorder/mic preamp

Low frequency cut-off (assuming a 3k Ohm recorder input impedence):
    •    High-pass filter off = 14 Hz
    •    High-pass filter on = 113 Hz

Dimensions and weight:
    •    width 67mm, depth 67mm, height 28.5mm
    •    weight 56g (excluding battery)

Specifications subject to change.  Hand-matched polyester capacitors are used for lowest distortion. They block plug-in power and phantom power from a recorder so that capsules are always powered with 8.3V plug-in power.