Audio Kits and Amplifier Boards

Parts Express has a great selection of DIY parts for audio projects as well as A/V cables and equipment.  They have recently added a DIY kits section to the website.  Most of the products are called kits but I would call most of them boards because come fully assembled and tested.   They stock Velleman and Parts Express brands.  You can find a lot of audio applications including AM/FM radio, MP3 player, and a few Class-D audio amplification boards.  The amplifier boards use Tripath, Texas Instruments and Power Analog Microelectronics chips.   For an example see the video below for the TK2050 Class-D Audio Amplifier Board.  It is one of the higher end kits at $44 US, they start at $9.90 for the 2x2W@4 Ohm Class-D.

Other sources of Class-D Audio amplifier boards:

Class D Audio Inc. Below is a pic of another Texas Instruments Amp.

International Rectifier

Jameco Electronics always has a good selection of audio kits and kits in general.  Here is an example of a guitar effects pedal built using the Perfboard Prototyping Kit.