Tiny Mic Preamplifier

Rajkumar Sharma      http://www.rajkumarsharma.com  
6655

A017

The Tiny Mic Preamplifier based is based on a single transistor amplifier design.  It amplifies the output of the electret condenser microphone.  Good choice for Karaoke.

Specifications

  • Power supply: 5 ~ 9 VDC @ 2 mA
  • Provides standard audio signal
  • PCB dimensions 26 mm x 56 mm

Schematic

SCH

Parts List

BOM

PCB

2 Response on “Tiny Mic Preamplifier

  1. The voltage gain of only 32.5 is much too low for a mic preamp. It should be 150 to 200. The gain is low because the low input impedance of the transistor loads down the high output impedance of the mic.
    The polarity of C1 is backwards. R4 and R5 are not needed.
    The transistor is biased wrong since it is almost saturated and loud sounds will cause clipping.

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