DIY microphone preamp

When trying to record a voice on a cheap microphone, many are faced with the problem that the speech is too quiet, and in addition to it, a strange noise is recorded, which drowns it at all.

To get rid of this problem, it makes sense to use a preliminary amplifier circuit that will amplify the incoming signal from the microphone and send it to the terminal device (in this case, a computer).

Scheme

How to make a preamp for a microphone with your own hands

In order to assemble this device you will need:

• Four resistors, nominal 4.7K (2 pieces) 470K and 100K
• Three capacitors 4.7 microns, 10 microns and 100 microns
• One transistor is KT315 or KT3102.

Attention! KT3102 is more suitable for this cascade, since it has a large gain and is less susceptible to noise.

• As well as an LED or diode.

Tools such as a soldering iron, pliers, glue, scissors and nippers are also useful for work.

As a board, you can even use a home-made surface, this is not so important. Then we assemble the cascade according to the scheme. As can be seen from the figure, the transistor is turned on according to the scheme with a common emitter. This ensures the best possible gain while avoiding spurious noises.

After all the elements are in place, you should solder the input and output connectors. Jack 6.3 should be used as input, as this is the most common microphone port. As an output connector it makes sense to make miniJack 3,5.

Also, do not forget to include a power switch in the circuit.An ordinary battery will be used as a power supply.

For greater reliability and beauty, you should choose the case in which this amplifier will be located. On the panel of the housing, drill holes for the connectors. If the user turned on the LED in the circuit, then a hole should be created for him. It will be most convenient to place it on the top panel.

After the circuit is assembled, you need to connect the microphone to one connector, and connect the other to the computer via a special miniJack-miniJack cable. After that, turn on the power on the device and check the sound quality. Noises should go away, and the volume and sound quality will increase.

Attention! These steps will only help if the user uses an inexpensive microphone. For better models, such a cascade is built into the device itself and there is no need to amplify the signal again.