The amplifier circuit has two main functions, it can work as a small and powerful amplifier. The power rating of 8 watts at 8 ohms impedance. The second one is that the IC can provide 2 to 22v supply and handle the medium current. I recommend you to use 500mA to drive the amplifier circuit.
The metal part of the IC is connected with the negative supply of the connection internally, so you can attach it into the metal case of the amplifier or heat sink.
Choosing TDA2050 as Equivalent
You can also use the similar component of the TDA2050 IC, which works almost the same as the LM1875 IC. Building a PCB or assembling this circuit is not difficult. If you are a beginner in audio amplifier making you must try this at first.
Circuit diagram
The circuit diagram may differ from the others. When connecting the speaker and the ground it is crucial that they both have a star point connected to the filter cap. If you are connecting them directly could make some noise and disturbances in the amplifier output.
The components labeled R2 are 100 ohms and which helps to reduce the interface from RF signals.
VR1 and VR2 represent the volume control and voltage selecting. When using the amplifier set the VR2 values in the middle for loudest volume.
Power supply circuit
