Introduction: Simple LM386 Audio Amplifier

The song is:
Infected Mushroom
semi nice


Q: The sound sUxx0rz, fix it!
A: Can't, since there are barely any parts.

Q: How do I add volume control?
A: Either in series with the speaker (volume) or between pin 1 and pin 8 (gain)

Q: Why is there a 7805?
A: To conserve power, you can go without it if you feel like it.


lworm (author)2011-10-06

Hey Kirbsome! I got a question. I'm some kind of new in that kind of projects ... So why do other users use Capacitors for their amps, what does that change?
Best Regards

Kirbsome! (author)lworm2011-10-09
Capacitors can do several things. In amps like this one, it's usually
  • To block DC from going through the speaker while passing signal, thereby conserving power.
  • To smooth out power going into the amp, thereby reducing a common humming noise.
  • Combined with a resistor to make a high / low pass filter, thereby making a tone control circuit.
The reason I didn't use any capacitors for this amp is because I tried using as few parts as possible, but if you want better sound quality I highly recommend them.
Hope this helps!
lworm (author)Kirbsome!2011-10-10

Hey Kirbsome!
Thank you very much - that helped alot, that was a great reply!
Have a nice day,

codestroy7 (author)2011-03-01

To anyone out there :)
Some of my music has heavy bass, but the amplifier cannot output it properly due to lack of power. Is there a way in which I can "precharge" the amplifier so that it won't lack power when a heavy bass comes?

Kirbsome! (author)codestroy72011-03-02

Well, it might also be the speaker (small speaker = no bass) but you could always try adding a low-pass filter

codestroy7 (author)Kirbsome!2011-03-04

Actually when i use DC adapters capable of delivering 5 volts at higher amperes, the bass is good, that's why i'am sure that its not my speaker. Since i want to create a pocket amplifier, adapters should not be considered as power source, so i want to know if i can create something like precharging the amplifier so that it will be ready for a bass comes.

Thank you for a reply i'll try putting a low-pass filter. i'll just post here what ever will happen to my amplifier :))

Kirbsome! (author)codestroy72011-03-04

As stated:
There's a lack of bass when there's a lack of power.
The only solution would probably be using some bigger batteries.
Maybe a DC-DC converter? I don't know.
But I do want to know how it works out for you :)

DaHandy (author)2010-12-15

Could you please post schematics for this? Thanks!

Kirbsome! (author)DaHandy2010-12-20


Johnny Lavabo (author)2010-11-05

I want to build this into something ( a music led box) i already made, but it has a 12 v power supply. Can i just add this to the same supply or do i need to do something else?

Kirbsome! (author)Johnny Lavabo2010-11-06

It should work just fine at 12v, you can use the 5v regulator if you want to.

AliB25 (author)2015-07-24

;) nice :D

AliB25 (author)2015-07-24

wasteroo (author)2014-04-15

This makes for a terrible amplifier, but it would be pretty good at keeping a very tiny cup of coffee warm

husmen (author)2014-03-10

Hi, is there any alternative of LM386 that I can use?

manugp (author)2013-06-04

I also have a Muvo

Kirbsome! (author)manugp2013-06-08

Aren't they great?

dritonsyla (author)2013-03-19

hei guys this is didnt work for me, coz is a noise, i dont have regulator butt im using adapter 6v, can u explain me what is the problem ?

dritonsyla (author)2013-03-19

hei guys this is didnt work for me, coz is a noise, i dont have regulator butt im using adapter 6v, can u explain me what is the problem ?

darkstranger94 (author)2013-02-10

Can you tell me a way to solder the mono jack, or what the little parts are for similar to what you did at the beginning of this video? Please and thank you.

samalert (author)2012-12-05

I am building 12v car LED strip sync with music using TIP31
Now i built it but those dont give enough Volts to lit the LED's bright, i read that one needs amp to increase the Voltage to TIP31 now constructing your circuitry help me do it ?

Kirbsome! (author)samalert2012-12-13

I'd like to help you, but I don't really understand you. What are you trying to do here?

astrogotnext (author)2012-08-30

hey what electronic device carries the lm 386 chip? what other chip could i use instead and where to get it out of.......

Kirbsome! (author)astrogotnext2012-09-02

I'm not sure I fully understand you here.

astrogotnext (author)2012-08-30

hey where can i find a lm386 chip, in what device or can i use a substitute,b-c i have a tm555a could i use that?

Kirbsome! (author)astrogotnext2012-08-30

LM386-es can be found in a wide variety of devices, from phones to R/C cars.

If you're unsure about your chip's specs, try to find a datasheet.

khubi (author)2012-07-16

pls how do i add a volume controll knob

Kirbsome! (author)khubi2012-07-17

Please read the other comments.

macsonservices (author)2012-05-12

this is great bro keep it up, i love your innovation

Kirbsome! (author)macsonservices2012-05-14

Reading this made me happy :)

macsonservices (author)2012-05-12

this is great bro keep it up, i love your innovation

mak24 (author)2011-10-24

hey Kirbsome....

i tried the circuit on a breadboard first and although i was getting the output it was tooo noisy... i mean... i pulled out the jack from my ipod earphones and connected them to my droid.. and used the wires to emulate the circuit on a breadboard.. but on a breadboard the output was too noisy... the song itself was not identifie\able over the jittery noise after sometime.

Kirbsome! (author)mak242011-10-25

what do you mean by "...used the wires to emulate the circuit..."
I want to help you out here, but I don't really understand the question.

mak24 (author)2011-10-24


how do you deal with the noise, i constructed the same on a breadboard and found too much noise

Kirbsome! (author)mak242011-10-25

If you mean noise like interference from outside sources, I'd suggest putting it in a grounded Faraday cage.
If you mean distortion from the amp itself, that's just it's sound.
There are barely any part in this thing, so the sound quality is bound to be crap.

wampastompa (author)2011-08-16

I just made my second one of these :)

jgonzález19 (author)2011-07-09

nice! (Y)

codestroy7 (author)2011-03-05

to Kirbsome.

i placed a high-pass filter to remove some of the very low frequency bass, now it sounds good. the next i'll try is removing the filter and applying a dc-dc conversion i think it will work but i'll just try to be sure. :) i'll just inform you what will happen next :)

btw. why did you suggested putting a low-pass filter? low-pass filter will remove high frequency audio right?

Kirbsome! (author)codestroy72011-03-06

Low-pass filters do not "remove" high frequencies, but rather dampen them.
I recommended a low pass filter since you said there's not enough bass.
Or did I misunderstand something here?

roeggebear (author)2010-09-20

ok i really want to make a amp but i can't find the amp chip in my broken sound system there is three chip that got same number as pins but it isn't a lm386 it is like a fm388 i think from top of my head im new to this stuff

Kirbsome! (author)roeggebear2010-09-21

So you're telling me you don't have a 386, good to know.
Tell me the exact part number and i might be able to help.

roeggebear (author)Kirbsome!2010-09-21

it is f4558

pfred2 (author)roeggebear2011-02-12

4558s are just dual op amps. They can amplify audio but they are not specifically designed for it. I'm using a dual op amp in this circuit as a preamplifier:

Hey Kirbsome my amp is made out of all scavenged parts too! It puts out about 15 watts.

Kirbsome! (author)pfred22011-03-04

Details please?

pfred2 (author)Kirbsome!2011-03-04

This is the page I got the schematic off of:
Though I modified it somewhat because I didn't feel like using a high voltage op amp. So I put regulators on board it to run the preamp. I scored some vintage JRC OP amps off a board I salvaged and used one on it. They rock!

That project is only so so a really hot one is this:

The schematic at the bottom of that page is the have all and end all! I took the one I made to a music store and let the guy there play with it some. After he got done all he could say was, how much do you want for it? I just smiled and said, not for sale. It is a worthwhile project to do.

I've my Eagle files for it but no way to host them. If you'd like I can try to attach them somehow here. A screenshot of the overdrive board:

codestroy7 (author)2011-02-24

What should i do?
The sound is too noisy. The noise is even amplified when i hold the wires from the audio source.

Kirbsome! (author)codestroy72011-02-25

Unfortunately, there's not much you can do.
This amp, it's... crap.

DaHandy (author)2010-12-26

Thanks for the schematics but I can't figure out where does the A cords go from the transistors... Could you please explain that?

Kirbsome! (author)DaHandy2010-12-26

The only silicon here is in the chip.

DaHandy (author)Kirbsome!2010-12-29

Are those pontentiometers then? Why aren't they shown on the video?

About This Instructable




Bio: Every single thing I make is from trash, I can't throw anything out! Well, most things are. Do you have any idea how hard ... More »
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