Comments on: Simple Mic Pre-Amp based LM358

By: Mayank Jain

Mayank Jain — Sun, 02 Mar 2014 12:06:27 +0000

what will be better lm358 or lm386 as i want the input from the microphone to be given to micro-controller

By: Brent

Brent — Thu, 19 Jul 2012 18:52:09 +0000

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).

By: Brent

Brent — Wed, 18 Jul 2012 23:02:10 +0000

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?

By: hamzeh

hamzeh — Fri, 06 Apr 2012 19:03:56 +0000

thanks for help

By: a.m.h

a.m.h — Sun, 22 May 2011 21:26:45 +0000

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

By: circuit diagram

circuit diagram — Fri, 22 Apr 2011 22:58:48 +0000

In reply to Blue Woman. 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.

By: Blue Woman

Blue Woman — Fri, 22 Apr 2011 11:43:09 +0000

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?