Lee Zhi Xian made this small low voltage audio amplifier for use with various devices and explains the how to of the projects and the advantages of the LM386 he used:
"Today, I am going to share on how you can make a low voltage audio amplifier. For this project, I am using LM 386 Audio Amplifier, which is commonly used among electronics hobbyist. I will break the article into a few sections. First, I will explain about the LM 386 chip itself. Then move on with some explanation on the parts used in this project. And finally, the design of audio amplifier.
Some of the advantages of using LM 386 Audio Amplifier is that you can power it with a 9V battery and enjoy the music. Besides that, the audio amplifier requires minimum amount of parts to operate as the gain has been set to 20 internally. However, further increasing in gain can be made externally. You can use it to amplify music from various devices such as mobile phones, laptop, or MP3 player."