This time I will post about datasheet of some IC that was applied to the power amplifier. Some of his IC from IC AN7143, AN7145L, AN7145H, AN .... , Up to BA5406. Here is the datasheet it in the form of images that you can download.
Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits. If you have a personalized circuit requirement you may feel free to request it through the comment box or contact me.