LM386 Audio Amplifier

I wanted to design an audio amplification circuit for a future project so i just wanted to design this one for now so i get an understanding of how it works. This is a very basic circuit that you can find all over using an LM386 integrated circuit i got from RadioShack.

Step 1 Obtain Parts

All Components can be found at RadioShack.

Multipurpose PCB with 417 Holes
5-15 Volt DC power supply (4 AA or 1 9v Battery)
8 Ohm Speaker
Audio Source e.g. iPod
8-Pin Retention Contact
IC1    IC                           LM386 Audio Amp IC
R1     Resistor               10 Ohm
R2     Resistor               1K Ohm
R3     Potentiometer     10K Ohm
R4     Resistor               10 Ohm
C1     Capacitor             220 Micro Farad
C2     Capacitor             10 Micro Farad
C3     Capacitor             220 Micro Farad

Comments

[J.Reynolds09]

I'm having some trouble with this project. Do you think you could post some better quality pictures of the underside of the board with caption notes of the connections and where they go to and from. I am not sure but I think that I have something hooked up wrong but I can't tell. I am a visual person so I tried to match how the bottom of the board looked but the picture isn't real clear. Thanks.

[ElectroFlex]

Would 1/2 watt resistors work?

[Enzomatico]

yes

[edfel01]

Where does pin 7 go to? thanks for any help

[J.Reynolds09]

pin 7 is unused

[David97]

Have a look at this datasheet on page 5. I dont know if it the same but it might be.

[dlhylton]

For a really good version of how to connect the LM386 correctly, check out:

http://www.learningaboutelectronics.com/Articles/How-to-connect-a-LM386-audio-amplifier-chip

[The Incredible IT Maker]

this may help. i have built 2 from this schematic. ita a really cool project. have fun.

[dlhylton]

I like this diagram a lot. Very clear, very concise. However, I would make sure to add more capacitors to get better signals in the circuit. I would add a capacitor after the DC power supply to clean up any ac noise that would be on there. I would add a ceramic 0.1uf capacitor to clean up ac ripple and a 100uf capacitor to act as a smoothing capacitor in case of current fluctuations. But great job.

To find out more about capacitor use in circuits, check out: 

http://www.learningaboutelectronics.com/Articles/How-to-connect-a-voltage-regulator-in-a-circuit

[Mr Sinster]

where it says input is that where you connect the audio source

[cmai00]

can you give me more info so I know how to connect it

[T0C]

I can tell you everything you need to know about this schematic, and some changes in there too.

[The Incredible IT Maker]

idk how to explain it. the picture is pretty much all the explaining you need.

[kilofeenix]

is your amp stereo? I watched a video on Mint tin amp by make magazine but the parts he uses in the video aren't the same as the schematic in the magazine.

[iApple guy]

Pin 5 is where C3 is if anybody was wondering.

[fretwreckef94]

Is it possible to add an LED into this which fades or pulses to the music?

[krmartin3]

Yep, when i built my portable speaker instructable and added the LED's to it they pulsed to the music. You will just have to mess around with R1 a little because the one i have there wont allow the LED's to pulse as well.

[fretwreckef94]

Where would i place the LED?

[krmartin3]

I put it in series with the power supply voltage so when the amp draws current with the beats, the LED flickers with the rhythm! I don't know if it is the best way, but it works well.

[tugung]

sir can you give me a diagram of that with led on it. please..

[lden hartog]

here is an led lighting controller, ridiculously simple, requiring only 2 parts! a standard npn transistor, and an LED. power source is 3-4.5 volts, double aa's work wonderful and you hook up the audio input to the SPEAKER OUT on your stereo. no worries, the circuit wil simply clip if turned up to high, and will deal NO damage to the led or transistor! uses VERY low power consumption! have fun!

[iApple guy]

I am in the making of one of these amps, but when I got to RadioShack they only had one 220mf cap so I will have to get one another day.

[anotherdragon]

I made my own and it's awesome man... Thanks

[dvdragond2]

Ive noticed that you have 3 resitors in the circit, why have another extra in the figure above and not show it in the schematic?

[big-s]

I just finished the project and it is great amplification, my only problem is it has some static like sounds coming from it. What could this be from? and how can i fix it?

[krmartin3]

could be a couple things. the radio shack speaker cannot handle much power at all so when you increase the volume it starts to distort the sound. also make sure the speaker is impedance matched with a resistor of the same or close to the same resistance. i think the best thing would be to get a bigger speaker, how many watts can the one you have now handle?

[big-s]

i have tried 3 speakers, they are 8ohm 3watt, 8ohm 5watt, and 4ohm 15watt. If you have any recommendations i used the same parts that you listed.

[codestroy7]

The audio has a little noise (hiss)...
how can i remove it?

[Bennett9831]

Actually no matter what there is going to be a hiss. I have a 1oowatt factory amp at my house and factory speakers. When I turn on my amp I get that hiss aswell. It is actually a good thing. If you here the hiss then you know the amp is in proper working order.

[David97]

Im not sure, this might tell you somthing.

[mixmo14]

where did you put the 10k ohms potentiometer resistor.?

[hightekrednek2396]

the pot is r3

[nshabbir]

can u plz send me a very clear view schematic diagram of this circuit

[David97]

I was looking at building somthing simmalar this datasheet has schematics on page 5.

[art.z]

Hi, I have a question.

Is a 220uF 35V capacitor enough for the output? Or it will have to stand higher voltages?
I noticed that the capacitor I have is smaller than the one you're using and I don't have a voltage meter to make sure.

Also, do I ground everything on the negative pole of the battery? Even pin 4?

Thank you!

[ski4jesus]

Hello, I built a small 386 amplifier also, and i hooked it up to a rather large magnet speaker, but small cone, and put it in the case as to make it portable(it was run by a 9v at the time) but then i added an output jack and a wall supply jack. but the bigger systems i hooked it up to had no amplification and it worked so much louder than the onboard speaker but also had so much less gain. not exactly sure why since they were about six times the size but they work wonderful. 386's are very fun amplifiers to play with.

[Misac-kun]

i'm doing a amp but with minimal parts (without resistors or capacitors) but i don't know where to hook up a led on this mess.

will it work by hooking up in parallel with the speaker?

[ankitgarg2005]

connect led between Vcc and ground use 500 ohm resistance in series with LED.

[Robot Lover]

You have to have a resistor for the led.

[manuferari]

awesome dude....I'm makeing this right now.