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The lm386 is a great tool to make a complete audio amplifier stage for a small project. It can drive a small speaker and handles a large voltage (operating) range. It's been used for many years by radio and audio engineering people due to its robustness and simplicity.
But it doesn't have a great gain! Mostly, this isn't important. However, with many types of radio receiver design, the only actual gain is at the audio end. This means that the little chip is pushed to its limits and starts making noises which we do not like!
To combat this, I have put a self biased Darlington preamplifier at the front end of the lm386 (the chip is actually just an OP amp with some extra controls and is simulated here with an EC OP amp)
Anyway, this is the idea here. It's very simple but works.
Yes, for all the tea In India, I am aware of newer class D chips and cheap modules from China. But, especially in radio, these suffer from production of noise which affects the receiver. They also sound sterile to my ears. Not warm at all. So there's still a good place for the old lm386!
This can achieve a 100 dB gain but we probably don't want this level and it can be brought down. Check out lm386 circuits online to see a real configuration for this specialist OP amp.
Enjoy!
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