How to build Low impedance microphone amplifier

 

Low impedence microphone are cheap and having more availability in the market. In case a high impedance microphone is used with any standard amplifier it is expected to give a better result though cost wise it is higher. In order to accommodate a low input microphone in a microphone amplifier as shown in the circuit an additional staff with a high gain transistor T1 is needed. In case a high impedance microphone is being used the signal can be directly connected to the junction point of capacitor C7 and the collector of the transistor. In this circuit the operational amplifier used is TL081 which is a low noise amplifier thus producing higher audio quality compare to its brethren. For any audio amplifier circuit the power supply is of highest importance. This circuit operates between 6 to 30V DC. It is to be ensured that the power supply is steady and with minimum ripple to achieve the desired result.

 

How to build Low impedance microphone amplifier

 

 

 

Parts List for the above Low impedance microphone amplifier circuit

 

all resistors are 1/4 watt 5% unless stated

  • R1=15k
  • R2= 150k
  • R3= 2k2
  • R4= 820
  • R6= 10k
  • R7= 10k
  • P1= 1M
  • C1= 3k9
  • C2= 100u
  • C3= 22u
  • C4= 4u7
  • C5= 470u
  • C6= 10u
  • C7= 100n
  • C8= 47u nonpolar
  • D1= 1N4148
  • U1= TL081
  • CN1= SIL6