20 Watt Stereo Amplifier-simple and Very Cheap





Introduction: 20 Watt Stereo Amplifier-simple and Very Cheap

About: i'm a college going guy who lives in india.i like to make electric gadgets and play with them.with the little knowledge of electronics,i'm able to solve my problems and hope yours too!!

want to listen to your favourite music loudly,but dont have any powerfull amplifier??want to have self made music system???are you getting bored of nasty and useless mono sound from tv,music player,dvd??want to have a self made cool and rich sound stereo amplifier but dont wanna spend alot???then your on the right place!!!!

this is one stop solution for all your problems related to stereo amps!!!!

guys this is my first instructable and i am quite new to instructables website,so dont be harsh toward my instructable.

today im gonna tell how to build high quality,simple,and cost effective amplifier.

this amplifier gives 20 watt output sound(really very loud!!!!)

# sailent features of the amplifier

* this amplifier is of 2 channel-stereo type.it is based on IC TDA 2009 chip.

* this project cost for me was only 96rupees (under 2$ USD).

* very easy to build

* requires only basic electronic knowledge.

* very few components.


please watch the video embeded in the last step to know the quality of the amplifier..

guys i have build this amp referring to the electric circuit website


please refer this website for additional information.

credits for circuit and pcb layout goes to electriccircuit website.

Step 1: Components Required

this circuit requires very less components.

main component of the circuit is IC TDA 2009A.please refer the datasheet for additional information on the ic


1) ic tda2009a

2) CAPACITORS 2.2uf/25v X 2 pieces; 470uf/25v X 2 pieces; 22uf/25v; 0.1uf disc type X 3 pieces; 2200uf/25v X 2 pieces; 100uf/25v

3)RESISTORS- 1.2k X 2 ; 18 ohm X 2; 1ohm X 2

4) a audio connector wire of earphones 3.5mm

5) copper board for etching.

7) soldier gun and some logic

NOTE-the 470uf capacitor in the schematics is equall to the 220uf cap in the pcb layout,you can use either of them.

Step 2: Hardest But Simple Step!!! ;)

we have to assemble the circuit as shown in the circuit diagram.

i have used a 6cm X 4 cm copper board.

just etch the circuit given on the board and drill the holes where the component have to be assembled.

Step 3: Assembly

we have to assemble the components into their places in the pcb.

now solder all the components in their places..DO NOT DRY SOLDER THE COMPONENTS .THEY WILL BE BURNT!!

attach the heat sink to IC before soldering it.this will prevent the ic from getting hot.

for heat sink i have used a L shaped piece of aluminium..

NOTE- the IC generates a lot of heat which has to be dissipated..here my heat sink is not enough large to dissipate the all heat generated...use the heat sink as large as possible.

Step 4: Supply, Input and Output

for input,i have used the old 3.5mm earphone audio input jack wire.

for output speakers- they should be atleast 15 watt rated speakers.

for output connection-to connect and disconnect the speaker i have used male/female AV connectors.

supply used here is of 15 volt 1.3A bench power supply.

if you dont have a proper supply.you can make it at home using ic 7815 regulator.google it for more information.also see the pdf file attached..

Step 5: DONE!!!!

hurray!!! we have just made a nice and simple cost effective amplifier!!!!

the ic and heat sink can become very hot so do not touch them while operating.


i have uploaded the video of this amplifier in work!!

thanx guys for reading my instructable and please VOTE for my instructable if you like it.



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64 Discussions

R5 and R6 are different values on the schematic. This is certainly a typo. How did you decide to go with 1 Ohm resistors instead of 10 Ohm resistors?

2 replies

thanx pal for reading my instructable.

i decided to use 1 ohm instead of 10 ohm because i thought less the resistance,more the power is delivered and more sound is reproduced!!!! its just a guess,i have used 1 ohm in my project...i just dont know what is the effect of the 10 ohm resistor...

Looking at the TDA2009a datasheet that you provided, the test and application circuit shows 1 Ohm resistors for R5 and R6, so your guess seems to be correct. From my limited knowledge of amplifiers, it looks like the C6/R5 and C7/R6 circuits provide high frequency stability where loudspeaker inductive reactance load can become excessive.


1 year ago

Hi Tiwari,
I used a 10k dual gang POT to adjust volume for 2 channels and this circuit working properly :D. now, I want to increase bass for this circuit but I dont know how to change this circuit. Could you please suggest the solution? thanks.

Are there any other chips that i can use instead of ic tda 2009a ?

Dear prabhat i don't understand to your ckt diagram....can you please simplify it with ic pin numbers

1 reply

great project

can i place your project on my website.

i'm working on a website which is related to electrical projects.

i also mention your name.

plz reply

1 reply

Yes ofcourse.and i will be appriciated if you mention my name and link of this instructable on your website.also please send me your website's address to me @ prabhattiwari22@gmail.com

Hi, I am a newbie in making diy projects and have very limited knowledge about electronics. So, I just want to ask if you bought the pre-printed PCB or if you etched the board to make the circuit?

Also, is it advisable use the perf board regarding the high level of heat produced?

2 replies

What resistor would you replace with a potentiometer if you wamted to be able to control the volume ?

1 reply

Hi, I have made this circuit recently but, it's not amplifying the sound, but lowering it. What could I have done wrong?

2 replies

It's working but just for a fraction of seconds it gives amplified sound just when I power it, and then very very low sound, almost nothing.

I think you have a loose connection to the amplifier chip legs