Stereo pre-amp lm358 Signal Amplification | LM358 Hi-Fi stereo circuit diagram | Audio Pre-amp

Hello friends,
Today in this blog I will be sharing a circuit for stereo pre-amp using lm358.
The circuit is very easy to build and is powered using a single power supply
5 volts to 12 volts.

Signal Amplification:

  In certain cases the output signal from some of the audio sources is comparatively less for the output driver stages, in such cases we employ a pre-amp circuit to increase the overall gain of the audio signal. Increasing the amplitude of the signal without any kind of distortion or change in frequency band of the input signal is known as signal amplification. However the use of coupling capacitors in the circuit limits the low frequency response of the signal.
Here below I am sharing the screenshot of the input and output waveform of 1khz sine wave signal. The gain calculated in this circuit was 5 times the input signal.

About Circuit :

The circuit is built around popular op-amp LM358. It is a dual operational amplifier. LM358 is cheaply and easily available around the local markets.
Input is applied on the inverting pins of Lm358 via coupling capacitor C1 & C2 and Resistor R1 & R2. R3 and R4 are feedback resistors. Output is drawn via decoupling capacitors C3 & C4.
The gain of the amplifier is given by
Gain= R3/R1 For channel 1
Gain= R4/R2 For channel 2
Resistor voltage divider is built using resistor R5 & R6 along with capacitor C5 & C6. This is a single supply topology so pin 3 and 5 should be connected to the output of voltage divider network i. e vcc/2.
The circuit can be powered anywhere between +5 v to +12v. The circuit was assembled on breadboard and was tested for desired results. The gain was 5 times the input signal on 1khz sinewave signal.

Circuit Diagram :

Applications :

* Stereo Pre-amp in audio amplifiers.
* Mic-preamp
* Guitar-preamp
* Signal Amplification Projects