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Low noise microphone preamplifier circuit

Here is two Low noise microphone preamplifier circuit. Which is simple circuit but high quality sound,includes devices that are selected very well.

This circuit can be used to all normal microphone, for example: the dynamic microphone of Europe zone that has impedance of about 200 ohms, the Japan microphone has impedance of about 500-600 ohms or others higher impedance microphone.

This circuit have 2 model are a balance Input Pre Microphone Amplifier circuit as Figure 1 and an Unbalance Input pre Microphone Amplifiers to can choose as you needed.

01-balance-low-noise-pre-microphone-amplifier


Figure 1 Balance Input Pre Microphone Amplifier circuit

How it works
Balance Input Pre Microphone Amplifier as Figure 1. The input signal will be sent to pin 3 and pin 5 of ICs, to increase signal. And send to pin 9-10 of IC3 that act as the differential amplifier. Thus, noise signal and various hum will be rid go away.

The output from IC3 will be increased again with IC4 to get the output signal as need.

The second section, the unbalance input as Figure 2 will see that the simple circuits by have two low noise ICs to connected together as the amplifiers circuit from microphone to high amplitude as need.

02-unbalance-low-noise-pre-microphone-amplifiers
Figure 2 Unbalance Input low noise pre microphone amplifiers

How to builds

You Just assembling equipment to the PCB correctly.
As Figure 3 and Figure 4
PCB-layout-of-balance-low-noise-pre-microphone-amplifiers
Figure 3 The PCB layout and components layouts of Balance Input Pre Microphone Amplifier circuit

PCB-layout-of-unbalance-low-noise-pre-microphone-amplifiers
Figure 4 The PCB layout and components layouts of Unbalance Input Pre Microphone Amplifier circuit

Should be used high-quality devices. For example: Metal Film Resistors, Which is a low noise.

All capacitors should be of high quality For example: polypropylene (MKP) or Polycarbonate (MKC) etc.

Parts you will need
UNBALANCE INPUT
IC1________NE5532, M5218P __OP Amp Dual General Purpose ±20 Volt 8-Pin DIP
R1_________680 ohms___1/4W Resistors tolerance: 1%
R2, R3______47K________1/4W Resistors tolerance: 1%
R4_________100 ohms___1/4W Resistors tolerance: 1%
R5, R6______1K________1/4W Resistors tolerance: 1%
R7_________8.2K______1/4W Resistors tolerance: 1%
R8_________100K______1/4W Resistors tolerance: 1%
C1_________1uF 50V __polypropylene (MKP) or Polycarbonate (MKC)
C2, C3______22pF 50V __polypropylene (MKP) or Polycarbonate (MKC)
C4_________1.5uF 50V__polypropylene (MKP) or Polycarbonate (MKC)
C5, C6______0.1uF 50V polypropylene (MKP) or Polycarbonate (MKC)
SW_________SLIDE 3P
BALANCE INPUT
IC1__________TL074__Quad Low-Noise JFET-Input General-Purpose Operational Amplifier
R1, R4________330 ohms ___1/4W Resistors tolerance: 1%
R2, R3________22K________1/4W Resistors tolerance: 1%
R5___________1.5K________1/4W Resistors tolerance: 1%
R6, R7________6.8K________1/4W Resistors tolerance: 1%
R8, R8________1.2K________1/4W Resistors tolerance: 1%
R10, R11, R13__5.6K________1/4W Resistors tolerance: 1%
R12___________4.7K_______1/4W Resistors tolerance: 1%
R14___________100K______1/4W Resistors tolerance: 1%
C1____________22pF 50V___polypropylene (MKP) or Polycarbonate (MKC)
C2____________1.5-1.8uF 50V polypropylene (MKP) or Polycarbonate (MKC)
C3, C4_________10uF 25V___Electrolytic Capacitors
C5, C6_________0.1uF 50V__polypropylene (MKP) or Polycarbonate (MKC)
SW____________SLIDE 6P

This Post Has 3 Comments

  1. Awesome Circuit.

  2. Hi Salim Khan,
    Thanks for your feedback.

  3. Can i use this circute with Condenser Microphone..

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