Preamp – Circuit audio preamplifier – IC LM358 dual op amp

| |

LM358 Low Power Dual Operational Amplifiers General Description
The LM358 series consists of two independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single
power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.
Application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM358 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional ±15V power supplies.

Unique Characteristics

  • In the linear mode the input common-mode voltage range includes ground and the output voltage can also swing to ground, even though operated from only a single power supply voltage.
  • The unity gain cross frequency is temperature compensated.
  • The input bias current is also temperature compensated.

Features Lm686 opamp

  •  Available in 8-Bump micro SMD chip sized package
  •  Internally frequency compensated for unity gain
  • Large dc voltage gain: 100 dB
  • Wide bandwidth (unity gain): 1 MHz (temperature compensated)
  • Wide power supply range: Single supply: 3V to 32V or dual supplies: ±1.5V to ±16V
  • Very low supply current drain (500 µA) — essentially independent of supply voltage
  • Low input offset voltage: 2 mV
  • Input common-mode voltage range includes ground
  • Differential input voltage range equal to the power supply voltage
  • Large output voltage swing

This circuit can be used in various situations where it is necessary to amplify the audio signal of low intensity, for example: How a microphone preamplifier. This present version is mono but if you need to mount a stereo just use two equal units.

Get new posts by email:
Follow us on social media

When mounting the preamp check all connections and components if everything is correct, connect the circuit to a battery source or in the range 9 to 20 Volts … Apply an input signal that can be for example a microphone and then adjust the 470K trimpot until the signal level suitable for your application … The adjuster will adjust the signal from 0 to maximum volume. To make connections to the input signal and the power amplifier to use shielded cables to avoid noise.

Schematic of the audio preamplifier integrated circuit LM358 dual op amp

Lm358 Preamplifier circuit PCB schematic

Suggested PCB mount preamp

Lm358 preamplifier circuit PCB
Lm358 Preamplifier circuit PCB layout
Lm358 Preamplifier circuit PCB silk

 List of material for assembly of the pre-audio amplifier IC LM358

C1, C2, C3, C4, C510µF/25V Capacitor electrolytic*
C6470µF/25V Capacitor electrolytic*
C7100nF – Capacitor ceramic
IC1LM358N – Low Power Dual Operational Amplifiers
Resistors 1/8W 5%
R1, R2, R3, R4, R5100k – Brown, Black, Yellow, Gold
R92.2k – Red, Red, Red, Gold
POT470K Trimpot horizontal mounting
INAudio Input Connector
OUTAudio Output Connector
VPower Supply Connector
Other: Solder, wire, printed circuit board, IC sockets, box, power supply, etc..

*for the power supply is 12 to 16 Volts.

Download the PDF to mount preamp: Datasheet LM158, LM258, LM358, LM2904, scheme, suggestion printed circuit board (PCB), the side covers, side components, Silk-screen.

Download PDF    Mirror


Download collection of circuits Tubes Audio power Amplifiers

Introduction to Breadboard (Protoboards), Part 1 of 2


4 thoughts on “Preamp – Circuit audio preamplifier – IC LM358 dual op amp”

  1. If you did in reality this circuit, then you would include DC feedback on the first amplifier.
    And so it’s just beautiful pictures and user deception.


Leave a Comment

Crash Course Electronics and PCB Design
Crash Course Electronics and PCB Design
DC circuits, operational amplifiers, EXERCISES, SIMULATIONS
DC circuits, operational amplifiers, EXERCISES, SIMULATIONS