Introduction: Simple LM386 Audio Amplifier

The song is:
Infected Mushroom
semi nice

FAQ:

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.

Comments

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,
Lenwo

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

Sure.

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

@kirbsome..

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.
Remember:
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:

http://img683.imageshack.us/img683/1641/p1010007ep.jpg

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

Kirbsome! (author)pfred22011-03-04

Awesome!
Details please?

pfred2 (author)Kirbsome!2011-03-04


This is the page I got the schematic off of:
http://www.redcircuits.com/Page1.htm
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:
http://www.gmarts.org/index.php?go=217

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

Transistors?
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?

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