Since we are working with only +12v supply we bias the op-amp by making a RC voltage divider. Ensure that the ground of signal in goes to virtual ground (vg in the circuit diagram) and not to the ground of the circuit.Ģ) The next block is a 2nd order sallen-key low pass filter which is responsible for band limiting the input signal to avoid aliasing. A small description of the various blocks is given below.ġ) The two 470 ohm resistors combine the stereo audio signal to mono audio signal. Notice that the microphone input board is removable or as they call it Modular. Note: Do not be bothered by the three MOSFETs and the screw terminals in the pictures.
