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

[watermaster13]

Do you have a video on how to make this amplifier

[tealk]

hey men, can i use 50k potentiometer?

[Lee_Smith]

do you know if you could tie the two audio lines to the same pot otherwise if i was to make a breakout from a regular headphone jack with two audio lines there would need to be two pots that would increase or decrease volume for each line.

[Dibin M Dixit]

Hey is it possible to use CMOS Op-Amp like CA3130E instead of LM386?

[Bulantuy]

help me to figure it out what is the problem on my amp because it dont work

[CHOCOLATEmeter]

how would ground be connected , im not used to seeing it in dc schematics. please explain.

[musick_08]

I need some help, does it matter what wattage the resistors are and what voltage the capacitors are?

[sagar.latti]

capacitors of 10uF will be of 63v and 220uF is off 50v and any resistors of that value you can use

[iApple guy]

All of the caps I used were 35v. I am unsure of the resistor VOLTAGE but maybe you mean OHMS?

[musick_08]

Alright, thanks for the reply. For the resistors I wanted to know what wattage they were. Some are 1/4 watt, 1/2 watt and so forth. I don't know a lot about capacitors and resistors other than the basics.

[iApple guy]

1/4 watt or 1/2 watt should be fine. Thats what worked for me!

[musick_08]

Thanks! I went to radioshack yesterday and tried this to no avail.. At first the amp just got distorted when the pot was turned all the way up, I added a 10ohm resistor to the middle lead on it and I did some other stuff I don't remember and fixed it. But now it is really quiet, even when turned all the way up. Do you know what I could do to fix this? I'm using a 12v 800ma power supply (output read 18v so I used a +12v regulator).

[iApple guy]

The LM386 is no high quality amp. It's generally used to amplify the sound at a normal volume. Not high. I bet there is a way to fix it but I don't know how to. I am going to google how to do it.

[sagar.latti]

Today i tried this exp.and its realy working but the output having some noise please tell me hoe to reduce it?

[ryantullos24779]

I have a question, could you use a different IC instead of the exact one you used? Would a UTC4558 circuit work?

[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.

[crazypanda01]

Using the wall supply jack would give the amp a full 120V which is much greater than your initial 9V supply. This would probably fry the 386 amp. Also the gain of the amplifier is based on the resistors and capacitors; so for lower voltages you get a greater gain because the instruments are scaled with the input voltage while the larger voltages receive some gain but compared to the input it is not much. If you look at the graph of amp gain, the output will never exceed the max power voltage input. So you're output voltage will never exceed 120V (coming from wall supply) but the 100k potentiometer can only move you up and down the slope a small amount compared to the total range. Hopefully this explain it.

[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

[darkside_501st]

The diagram on this link doesn't show the negative line from the speaker connected to the ground, but it should be right?

[lau1406]

sorry for my bad English.

I have exedently switchet c2 and c3 but it works. do I have to switch them back or not becouse it works?

[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.

[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

[Kante Tech]

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..

[iamdarkyoshi]

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!