I wanted to build an amplifier for a spare set of 4 ohm 20W speakers I have laying around. After three days of searching circuits on the internet and trying them out on a breadboard not having much knowledge in amplifiers, I've finally managed to piece together this circuit that actually amplifies the signal instead of doing nothing. The problem that I'm having is, there's a slight amount of distortion at any input amplitude. RV1 has been tuned to drive the opamp just enough to 0V before the output starts clipping, directly hooking the inverting input up to 0V distorts the audio like crazy. Not having and oscilloscope and only a cheap multipeter how would I go about improving this circuit? Changing R1 and R2 to something lower makes the problem worse, to something higher and nothing happens, above 10k and the amplification fades away signifficantly. And the LM358 is the only op-amp I have
The reason why I used MOSFETS is because I've had them laying around and nothing else. And yes the power source is sketchy atm but that'll be changed out for a proper power source once the circuit is finalised and works without distorting.