The integrated amplifier that is smaller. For listening in a small room. Must have good the sound quality. Low noise and cheap.
This is Super stereo pre tone control project using LF353 low noise op-amp, easy to builds with PCB can adjust bass treble and volume on one PCB board.
The Dynamic Microphone Preamplifier circuit. So low noise signal,use three transistor (2SC945, or 2C1815 or 2SC828) is transistor amplifier with a low noise [...]
This is cheap & small hearing aids circuit,use increase sound to head phone with 1.5V AA battery, and all transistor and a few components with small PCB [...]
A tri audio amplifier has three in one amplification act drive specifically each audio speakers good quality, using TDA2030 and crossover network built-in [...]