3 Simple Audio Booster Circuit

What this circuit does is boost the audio signal from microphone, guitar or any sound generator. It amplifies signal from millivolts to few volts but it increases also its impedance thus connecting the 8 ohms speaker directly to the output will not work. You can series this circuit to a buffer circuit to convert this high impedance to low impedance.
audio booster schematic
2N222 pinouts
Part List:
R1 - 390 kilo ohms 1/4W
R2 - 47 kilo ohms 1/4W
R3 - 10 kilo ohms 1/4W
R4 - 560 ohms 1/4W
Pot1 - 100 kilo ohms potentiometer
C1 - 330uF electrolytic capacitor rated 10V (min)
C2, C3 - 2.2uF electrolytic capacitor rated 10V (min)
Q1 - 2N2222 or similar NPN transistor


  1. Am I able to connect this to a LM386 amp I made? So instead of me hooking my iPod up just to the LM386 amp, it would be hooked up to this, then this would be hooked up to the LM386 amp? And if I can do that, would it be any louder then just using the LM386 amp by itself?

  2. You can use it but not really necessary and it doesn't increase the loudness of your LM386 amp. This circuit is already built in LM386 IC.

  3. This article is very good. This scheme can be online simulated (in order to see amplification depending on R3 and R4 and hFE on following: