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How to make a preamp out of transistors? Answered

I am wondering how to make a simple and cheap preamp for a microphone for recording audio on the computer. I would prefer to use no chips.


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Best Answer 9 years ago

There are some ideas here.

Quercus austrina
Quercus austrina

9 years ago

Those are good starting points. Have a look at my preamp on the Nuts n Volts forum. It is stereo and works for standard dynamic Mics and can be plugged into a computer's line in jack or other consumer electronics line in jacks.

Take note that the schematic is the "test version" in that R15 was changed to 10K, S1 and S2 are actually a single DPST switch and you can ignore the 10% after R1 and R2 (that is a default of the design software).
Switch S5 allows you to feed 1 mic to both sides (Mono switch).
Switches S3 and S4 are Bass Contour switches - 10uF is Thin while 100uF is Fat.

This preamp is based on this mixer design. The version I have built is very quiet (noise wise) and sounds very clear.

Good luck on whichever preamp you build,