Simple Stereo Amplifier 2x1W - LM386





Introduction: Simple Stereo Amplifier 2x1W - LM386

In this instructable I will show you how to make a 1 Watt stereo amplifier with LM386 single supply low voltage audio amplifier.

It can be powered by batteries with voltage range of 4V to 12V or by 12V wall adapter.

Step 1: Demonstration

In this video you can hear the amplifier.

Step 2: Parts List

For this instructable you will need:

1x - enclosure (KM60)

some perfboard

2x - LM386 single supply audio amplifier

1x - 7809 voltage regulator (9V)

2x - 1n4148 general purpose diode

1x - LED 5mm

1x - 1000µF electrolytic capacitor

2x - 220µF electrolytic capacitor

1x - 100µF electrolytic capacitor

3x - 100nF ceramic capacitor

1x - 10kΩ logarithmic(audio) stereo potentiometer - if you can't find logarithmic you can use linear as well

1x - 4.7kΩ resistor

1x - DC power jack

1x - 9V battery clip (6f22)

1x - 3.5mm stereo jack

1x - double pole double throw(DPDT) switch


2x - 8pin DIP socket

1x - 6.3mm stereo jack

1x - Potentiometer knob

Step 3: Schematic and PCB



C1 and C2 are required by the regulator to ensure stability. C3 is for low frequency filtering. LED1 signalizes power. IC3 regulates the voltage to 9V. If a battery is used it is connected to BAT connector because connecting them to the regulator would waste power. BAT42 shottky diode may be used for D2 because it has lower voltage drop. I also advise to use a DPDT switch that switches batteries ON/OFF and adapter OFF/ON if not done so the amp would allways be on because of the allways connected batteries.


The signals are fed from IN connectors to stereo potentiometers which control the voltage of the input and therefore the output volume. IC1 and IC2 amplify the signal. C5 and C7 filter high frequencies from the output. C6 and C4 protect the speakers from DC voltage which could appear by accident.(speakers don't like DC).

To make the schematic and board I used a free program CadSoft Eagle which I would recommend to anyone making schematics or PCBs.

Step 4: Drilling the Enclosure

Unfortunately I do not have any photos of this stage but all I can say is that everything went as usual except for the speaker holes. As I did not have a proper size drill bit I chose to drill many smaller holes around the circumference and then broke the excess plastic off. After that I filed the holes so they resemble a circle.

Step 5: Wiring Diagram

Now comes the fun part of wiring all the components that will be attached to the enclosure. The images should clarify it.

Step 6: Conclusion

For me this was a fun project, especially drilling of the speaker holes. If you manage to build this project don't forget to post your results into the comments.



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14 Discussions

mine does not work either the light bulb just blinks and the audio


Question 4 months ago

My circuit doesn't work. I've checked continuity and everything seems ok. Another possible problem?

This looks amazing. Definitely trying this out! How would you go about and do it on a breadboard? (Sorry I am new to electronics!)

I make both sets of this should I connect power and audio in parallel to each set

Nice project,although i would like to see a clearer schematic.

3 replies

Click on the image then right click and select show picture. Then you should be also able to zoom.
Or did you mean something else ?

I meant something else ,the way the LM 386 is shown in the circuit: not as a triangle but a rectangle,I find it easier to follow it that way....

oh I'm sorry, that's just the way it looks in eagle.


can i use 12v power supply for this? ithink it must be possible becouse 7809 will regulate the volthage to 9v.

1 reply

Radio Shack used to sell aa LM386 stereo preamp much like what you built. I used one in my arcade cabinet and another to amplify the output of my crystal radios.


Nice amp project. You should enter it in the Amps and Speakers contest that is cuurently running