PAM8403 6W STEREO AMPLIFIER TUTORIAL

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Intro: PAM8403 6W STEREO AMPLIFIER TUTORIAL

This instructable will guide you through the steps of using the PAM8403 CLASS D DC STEREO AMPLIFIER.

Step 1: BASICS

THIS TINY AMPLIFIER OPERATES ON 5V DC AND PRODUCES AN OUTPUT OF 6W ( 2 X 3 W ) .

This is one of the cheapest and most powerful stereo amplifier, provided with proper wiring and power sources.

The IC does not require a heat sink, so this will be perfect for your custom speaker project.

This amplifier costs about 80 cents in the U.S and around 50 Rupees in India.

The dimension of this board is 2cm x 2cm only !!!

DON'T SHORT THE GROUNDS OF THE LEFT AND RIGHT AUDIO OUTPUTS WITHOUT USING A . There will be a schematic below if you want to attain common ground for making headphone amps.

AVOID PROVIDING MORE THAN 6 Volts.

I WILL DEFINITELY NOT RECOMMEND YOU TO BUILD THIS ON A BREADBOARD, THE DISTORTION RATES ARE HORRIBLE !!!

USE CO-AXIAL CABLES FOR THE DC INPUT AND AUDIO INPUT. FAILING TO DO SO WILL RESULT IN HORRIBLE RF INTERFERENCE AND BAAAD AUDIO OUTPUT.

THE AMPLIFIER BOARD COMES IN TWO VERSIONS, ONE WITH VOLUME CONTROL AND ONE WITHOUT. There's a schematic below to add your own volume control.

Step 2: THE CONNECTION

The board basically has every connection labels imprinted so you don't need to go through rocket science for the connections.

Anyways, as i had mentioned earlier, use a shielded cable for the inputs. Normal wiring can be done for the outputs.

Find yourself a aux cable or any cable with a male stereo pin.

NOTE : SHORT THE GROUNDS OF THE AUDIO INPUT AND THE VOLTAGE IN

Step 3: FOR TRS PINS ( 3 Leads)

You will find three wires in basic aux cables, two of them are signal wires and one is the ground, usually the black or yellow wire is the ground.

IF YOU DON'T KNOW WHICH WIRE IS CONNECTED TO WHICH LEAD:

1) GET A MULTIMETER AND SWITCH IT TO CONTINUITY MODE

2) Connect one cable of the MM to the bottom lead of the pin and the other cable to any wire

3) IF you hear a beep then it means that those two terminals are connected to each other.

4) Do the same for the signal pins. Anyways you can interchange left and right signal inputs, it doesn't make any difference to the circuit.

SOLDER THE WIRES TO THEIR RESPECTIVE PADS.

Step 4: FOR TRRS PINS ( 4 Leads)

In this case, there will be four wires, two for signal, one for ground and one for +ve voltage in, this wires is basically for the inbuilt microphone of your earphones/headphones.

You will require only the SIGNAL AND GROUND PINS.

Step 5: THE USB CABLE

Ok so you will see four wires, +ve V, -Ve V, Data -ve and Data +ve .

You need only the +ve and -ve V wires.

Solder them to onto the respective pads on the board.

You will usually find aluminum shielding below the first plastic layer, strip that off, then you will find aluminum wires surrounding the four colored wires,, strip them off too.

Step 6: CONNECT YOUR SPEAKERS

This amplifier is capable of driving any speaker! In my test i had it connected to two 8 Inch subwoofers rated 8ohms 100Watts each. But yeah, it won't be spitting out it's peak output power and you won't be satisfied with it if you use huge speakers! ...

SO THE SPEAKERS TO GO WITH THIS AMPLIFIER IS :
Any FRS rated 4- 8 ohms 10 Watts

or any other speaker with an impedance of 4-8ohms and 10watts power...

BEST RESULTS CAN BE ATTAINED USING 4 Ohms 3 Watts speakers.

NOTE : DON'T SHORT THE GROUNDS OF THE SPEAKERS, THIS WILL DAMAGE THE IC. FOLLOW THE CIRCUIT BELOW TO ATTAIN COMMON GROUND

Step 7: VOLUME CONTROL

1) Get a 10 K ohms Audio taper stereo potentiometer ( in simple words, two potentiometers with single knob resulting in same output)

2) Connect the left output to the top left pin of the pot

3) Connect the negative of a 10 uf electrolytic cap to the top middle pin of the pot and connect the positive of the cap to the amplifier's left input.

4) Connect the top right pin of the pot to the amplifier's ground.

5) Connect the right output to the lower left pin of the pot

6) Connect the negative of a 10 uf electrolytic cap to the lower middle pin of the pot and connect the positive of the cap to the amplifier's right input.

7) Connect the lower right pin of the pot to the amplifier's ground

NOTE: IN THE SCHEMATIC, THERE ARE TWO POTENTIOMETERS , DON'T GET CONFUSED, IT's TO DEPICT THE STEREO POTENTIOMETER ( 2 in 1 Pot ) .

Step 8: COMMON GROUND

IF you are looking forward to make a headphone amplifier, you can't directly short the ground pins of the output, please follow the above circuit.

Step 9: TEST IT OUT

Connect the power supply

It's normal to hear slight humming from your speakers before connecting your audio cable.

Connect your audio cable, now the humming should have disappeared.

That's it!!! Play your track and comment below if you have any issues with the amplifier and i will try solving it :D

Thanks and stay tuned :D

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20 Discussions

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DraženB6

Question 6 weeks ago

I bought this Micro USB 5V PAM8403 Bluetooth Digital Audio Receiver Stereo Amplifier Board
Is it better to connect with booster step up 5V module or directly from the 18650 battery?
Thanks!

1 more answer
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RhastaDraženB6

Answer 6 days ago

I am currently using it at 3.3V and it is doing just fine. The datasheet says it's good for 2.5V to 5.5V with an absolute max of 6V. A 18650 should be good enough.

Edit: At lower than 5V you will be able to output less power though. 1.6W at 3.6V with 4ohm speakers. And only 0.9W with 8ohm speakers.

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kaizenNakamotoshinjanroni.1995

Answer 15 days ago

Step 7 is used to add volume control, basically you take ur audio input say from your phone through an aux cable and add a POT in between to limit the current entering your PAM8403 amplifier thereby controlling the volume
I guess ur 6.5 ohm would work.

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HormuzdyrG

Question 4 weeks ago on Introduction

Hi i picked up a Bluetooth amplifier kit as shown in the attachment. However when I went to a speaker shop to match, the 4ohm 20watt speaker did not relay music as expected. It was mild or non existent actually. The volume of the mobile was at full limit. Is there something wrong with the chipboard or the speakers were incorrectly matched. Do I need another amplifier, volume control etc

IMG_20180921_194144.jpgIMG_20180921_194101.jpgIMG_20180921_194118.jpg
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Deepak2512

7 weeks ago

I am using a 12 V adapter with 7805 to power both, the PAM 8403 and the Bluetooth music receiver im using. I am not getting any sound. There is a constant bleeping from the speaker.

But when I use different power sources for the amp and Bluetooth music receiver, they work perfectly fine. What could be the issue? Please help

2 replies
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AlG45Deepak2512

Reply 7 weeks ago

Probably a ground loop problem. When you power both the amplifier and bluetooth modulle from the same power source this can be a problem. You can eliminate the ground loop by adding a Murata NKE0505SC on the power input of the bluetooth module. See this youtube video:

bluetooth ground loop isolation

https://www.youtube.com/watch?v=b2Pb1KuVDS0

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AlG45AlG45

Reply 7 weeks ago

There are also modules available that incorporate both the pam8403 and bluetooth in one, so probably no need for additional ground isolation would be required. About $2.50 . Google:

"Mini 2X 3W PAM8403 Bluetooth 4.0 stereo digital amplifier micro USB powered Amplifier board module"

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BharathC11

Question 5 months ago

Hey, I have 5 w speakers, when I have connected them directly to the phone ,audio was not clear. And when I tried to connect speakers with phone via Bluetooth, it was fine for a while,but suddenly audio stopped playing and noise was coming out of the speaker and as a result the membrane of the speaker was vibrating with high frequency. I don't know what to do, please help me??

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RoyL37

Question 6 months ago on Step 8

Can capacitors C1 and C2 in the Common Ground circuit be electrolytic capacitors, or do they have to be ceramic capacitors or other non electrolytic capacitors?

1 more answer
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KarlL41RoyL37

Answer 6 months ago

both is possible. If you use electrol.caps, make sure + goes to amp, - to speaker.

Be warned that PAM8403 creates much more distortion when used single ended.

It makes a very bad (IMHO unusable) headphone amplifier !

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alan monro

9 months ago

It doesnt matter what physical size of speaker you use , the sound output doubles with every 3 db increase in sensitivity of the speaker , eg , if you use a spkr of 80 sensitivity and then use a spkr of 95 sensitivity you get 5 times the sound output . Also dont forget to use 4 ohm speakers ............... Alan (audio technician)

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TheElectroSTUDedwinl33

Reply 1 year ago

I see your idea is to double the output but no, that's not possible.

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edwinl33TheElectroSTUD

Reply 1 year ago

I mean the input voltage of two PAM8403 is it possible to connect it in parallel.

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TheElectroSTUDedwinl33

Reply 1 year ago

Yes you can. just make sure your input voltage is a stable 5V line...

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MuhammadS508TheElectroSTUD

Reply 11 months ago

Just tell me why is there a problem connecting a subwoofer to the pam8403.

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shais8

11 months ago

also can i connect it to usb port?

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shais8

11 months ago

are the capacitors needed pls help