Low noise Mini Electret Microphone PreAmplifier

Rajkumar Sharma
34776
Views
easy
Tested

The single supply microphone pre-amplifier amplifies the output signal of an electret capsule microphone to audio line levels. An op amp is used as a trans-impedance amplifier to convert the output current from the microphone in to a signal level voltage. The circuit works with 9V so it is good choice for battery operated systems.

Features

Supply 9V DC
Current Approx. 3mA
On Board Microphone
Very thin and narrow PCB

Schematic

Parts List

Photos

Video

OPA172 Datasheet

opa172

PCB

Downloads

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Comments

JensJ

Thank you for this. Modified it to run on a 5V supply and using another OP-Amp and it works perfectly with those alterations.
2 years ago

Reply
- Mike
  
  Could you let us know what modifications you have done to this circuit and why?
  2 years ago
  
  Reply
Dan Gonzalez

the capacitor C5 is well polarized in the diagram, or is it a misprint
7 months ago

Reply
- Mike
  
  Thanks for noticing this fault. We fixed it above in schematic
  7 months ago
  
  Reply
kenahilton

I want to purchase the above microphone preamp. What is the cost in USD and how do I get it?
5 months ago

Reply
- Mike
  
  Thanks for your interest in this board. Please check your email for more details.
  5 months ago
  
  Reply
Javier

Hi! Is it possible to hear some real sound tests? is it possible to get a copy of this mounted for experimental purposes? thanks and good job!! 🙂
4 months ago

Reply
- Mike
  
  I am sorry, all i have for now is the video above, and we don’t have a sample on hand, but we can produce the board in quantity if you are interested.
  4 months ago
  
  Reply
Phil Stewart

Hi,
I’m interested in several of these — more if they perform well.
How is performance in the presence of RF interference & nearby electrical devices? The PC board is pretty basic — does it require shielding?
I am interested in either the PC board or assembled device, depending on price. Thanks!
3 months ago

Reply
- Mike
  
  Could you email me through the form here: https://www.electronics-lab.com/contact-us/ and I will contact you with a quote.
  3 months ago
  
  Reply
Simon Rung

Hi!
How much for an assembled device?
For now I’m in a prototyping face and i would like to try one of these out.
3 months ago

Reply
- Mike
  
  Sorry, these will have to be produced on order, so our minimum is 10 boards. Will this work for you?
  3 months ago
  
  Reply