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Simple Mic Pre-Amp based LM358

Posted by on Mar - 4 - 2011

Here the simple audio mic pre amplifier circuit based on single IC LM358. The circuit is very simple, inexpensive and easy to built.
Simple Mic Pre Amp based LM358 circuit

Component Parts List:
R1, R3, R4 = 10K
R2 = 1K
R5 = 100K-1M Potensiometer
C1 = 0.1uF
C2 = 4.7uF/16V
IC1 = LM358 dual op-amp single supply
Mic = Electret Microphone

Notes:

  • Use R5 to adjust the gain of op-amp LM358.
  • The LM358 has dual op-amp module, you may build stereo audio pre-amp using single LM358.

Download LM358 datasheet here

The circuit designed by Tony van Roon

Categories: Pre Amplifier
Tags: audio mic pre-amp circuit,  LM358 circuit,  LM358 datasheet,  mic pre-amp design,  mic pre-amp diagram,  mic pre-amp schematic,  op-amp LM358,  simple mic pre-amp, 

Scheme related to Simple Mic Pre-Amp based LM358:

7 Responses so far.

  1. PC World offer brings Motorola Xoom price.. back down again.. | Dektau says:
    March 5, 2011 at 8:36 am

    [...] Simple Mic Pre-Amp based LM358 « Circuit Diagram [...]

  2. Blue Woman says:
    April 22, 2011 at 7:43 am

    Hi,

    Q1. You have a power supply of 9V in the circuit. Will this circuit work if I have a 5 V supply? If it can, then obviously the values of the capacitors and the resistors would change. Are there any rules or equations that I may need to calculate the values of components if I have a 5 V supply?

    Q2. Where does the output of the system go to?

  3. circuit diagram says:
    April 22, 2011 at 6:58 pm

    Q1: Yes, this work with 5V supply. LM358 has a wide rang voltage supply of 3V to 32V. You may try to lower the R1 value.
    Q2: The output will be to the mixer circuit, echo chamber, or directly to the tone control circuit.

  4. a.m.h says:
    May 22, 2011 at 5:26 pm

    hello
    i want amplify the weak audio signal. in your point of view which of this op-amp suitable:
    lm358 vs 741?

  5. hamzeh says:
    April 6, 2012 at 3:03 pm

    thanks for help

  6. Brent says:
    July 18, 2012 at 7:02 pm

    I tried building this for my guitar as a test. My output from C2 before I hooked the guitar up was floating around 3.7V, so I grounded it with a 100k resistor (high-pass filter). Is this normal, or did I hook something up wrong? Also, I only seem to be getting voltages above the output, isn’t the point of the voltage divider on pin 3 to allow signals to oscillate around 2.5V up AND down?

  7. Brent says:
    July 19, 2012 at 2:52 pm

    I rebuilt my circuit this morning and got better results. The oscillations are now proper. I do still have a DC offset, but I guess something like a speaker will only catch the alternating signals any way (I ditched the resistor I had added to the output cap).

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