I am trying to build an audio system . I have a speaker which is rated 10 W and 8 Ohms . I am using a circuit from datasheet of TDA2040 with a pre-amplifier circuit with the microphone . when I connected it on a breadboard it seem to work fine at low volume but when I raise the volume the speaker starts to beep and sounds becomes unclear.
instead of variable 100Kohm ~ 1Mohm variable pot I am using a 100Kohm fixed resistor.I am using a variable pot between the the two circuits to control the volume.I am powered the TDA2040 circuit with 12V 1A adapter and pass the same source through a regulator to the Pre-amp circuit.Are there possible reasons makes the speaker beeps at high volume ?