I built the TDA 7052 circuit from the datasheet and connected it to my computer's sound card and a 50 \$\Omega\$ speaker.
Here's the circuit:
The \$R_s\$ is the source impedance, which I can't measure and sound card manufacturer isn't providing any useful information. I also used 100 nF electrolytic capacitor, since I don't have any ceramic at the moment.
I already know that the speaker and the amplifier can work well together, because they were salvaged from another circuit.
Now about my problems:
First problem is that the amplifier won't work on voltages above 3.1 V. The minimal voltage listed in the datasheet is 3 V, typical is 6 V and maximum is 18 V, so this looks a bit strange.
The next problem is that I get crackling and noise when I set the computer volume to more than 50%. The speaker is quiet (much more than in the radio I got the amplifier and speaker form) and from time to time it seems as if the amplifier is clipping (I'm not sure if that's the right word. The peaks seem to get distorted).
Here's the effect of increasing volume on a sine wave:
I should also mention that this is my first circuit on a breadboard, so it could be causing problems too.
So where do I start fixing this?