This module takes the balanced stereo pair as XLR inputs and uses the SSM2141 line receivers to crete a single unbalanced signal for each channel. These two signals are then electrically summed and buffered using an NE5532 device. This module was used as the stereo to mono converter for the mono balance check monitor project.
A trimmer allows adjustment of up to around 8dB of gain to compensate for the summing network losses.
To calibrate this, apply the same signal to both inputs at 0dBu and calibrate the output of the summing module to 0dBu. Alternatively, apply a balanced signal to one input and calibrate for -6.0dBu at the output. Check that the same happens when the signal is applied to the other input.
|BIM-2 Circuit (pdf)||BIM-2 BOM (pdf)||NE5532 Data Sheet (pdf)|
|BIM-2 PCB (pdf)||SSM2141 Data Sheet (pdf)|