Wednesday, June 15, 2011

Audio Mixer based JFET 2N3819

This is the audio mixer circuit based Junction FET (JFET) of 2N3819.

Audio Mixer based JFET 2N3819 circuit diagram:

Audio Mixer based JFET 2N3819 circuit diagram

Audio Mixer based JFET 2N3819 Parts List:
R1, R3 = 10K Pot
R2, R4 = 100K 1/4 W Resistor
R5 = 6.8K 1/4 W Resistor
C1, C2, C3 = 0.1uF Capacitor
Q1 = 2N3819 Junction FET

Circuit Notes:
  • As numerous or as few channels as are needed may be added to the mixer. Do this by just duplicating the input "sections" that are shown on the schematic design.
  • A shielded case is perhaps necessary to minimize hum and support to avoid oscillations.
  • The Audio Mixer circuit could be powered by a single 9 volt battery.
Original circuit page: go to this page

About Audio Amplifier
An audio amplifier is an electronic amplifier that amplifies low-power audio signals (signals composed primarily of frequencies between 20 - 20 000 Hz, the human range of hearing) to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain.

The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification, equalization, tone control, mixing/effects, or audio sources like record players, CD players, and cassette players. Most audio amplifiers require these low-level inputs to adhere to line levels.

While the input signal to an audio amplifier may measure only a few hundred microwatts, its output may be tens, hundreds, or thousands of watts. More explanation about power audio amplifier can be found at

This is a video tutorial about how to a very simple audio amplifier based on the LM386 amplifier chip. It can be built for less than $20 (or might be less than $8 in some countries) and used to amplify any low level audio signal including a guitar, bass or mp3 player.

Watch the video:

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