Here is Class A amplifier circuit. It have good sound Distortion-free. First use main are transistors only. Second: 5W output use IC-low noise IC,MJ2955 power transistors [...]
This is three Simple 50w OTL audio amplifier circuit by 2N3055, can build easy and cheap, It's durable and very loud sound , Not needed speaker Protection. [...]
Although it is ancient, it is still interesting.