Buzzing sound in class D audio amplifier

[Riyas8123]

I have a PAM8403 audio amplifier which is a class D amplifier. But I hear a buzzing or cracking sound only noticable at high volumes.

So far I have done the following steps:

1. Tried to add a capacitor at input to provide surge current.
2. Added a simple capacitor in series to help the audio get rid of DC. Even though the board has one.

But I dont know what else to try.

[cheater]

This is a tiny circuit - are you sure you're not exceeding its power handling capability?

[Jwillis]

In the application note 2 on page 7 of the datasheet it says "When the PAM8403 works without LC filters, it's better to add a ferrite chip bead at the outgoing line of speaker for suppressing the possible  electromagnetic interference. "