This is small integrated amplifier at 20W using a TDA2004 or TDA2005 IC,use 12V supply for BCL car audio amps[...]
This is a small Stereo amplifier 3W + 3W using BA5406-IC. It use 12V power supply as source of this project. and use a few part so easy to build.
This is TDA2009 bridge amplifier circuit BCL 18W,Supply volt = 23V 2A, it is 10 +10W STEREO AMPLIFIER integrated circuits interesting again the one number.