This is a bridge amplifier circuit which built using dual power IC TDA2006. Each IC capable to deliver 12W power audio output as explained on TDA2006 12W amplifier circuit. The double TDA2006 will also double the gain.
Here the circuit design diagram:
The power amplifier IC TDA2006 provides high output current and has very low harmonic and cross-over distortion. Further the device incorporates anoriginal (and patented)short circuit protection system comprising an arrangement for automatically limiting the dissipated power so as to keep the working point of the output transistors within their safe operating area. A conventional thermal shutdown system is also included.
Download TDA2006 Datasheet
This is the video tutorial about how to build a realy simple headphone amplifier. The circuit powered with 9V battery and use an IC to amplify the input signal from mp3 player.
Watch the video: