Shown right is a graph comparing input and output signals. The gain is set at -10 for better illustration, (the minus means it's inverted)
If the signal sounds distorted, it is likely that the wave is clipping. This is when the top and bottom of the sound wave are lost, clipped. This is because the amplifier cannot produce large enough output voltages due to the supply voltage being too low.
If viewed on an oscilloscope it might look something like the lower graph.
There are a few ways to get around a clipping output. Try the following:
- Increase the power supply voltage - but do not go above 18 volts.
- Reduce the input signal using a volume control (preset or potentiometer).