Picture of 10W R.M.S. Audio amplifier
                             The aim of the project was to make an audio amplifier that can deliver up to 10W R.M.S. power output. input can be given via computer/mp3 player or a mic (mic circuit explanation at the end). there are many different types of amplifiers tda2003 is probably a class b amplifier because its power consumption is quiet low then normal amplifiers and also that its noise is very low.
the purpose for which i chose this ic is that it has very less external components, very low distortion,very low input power and a corresponding high output power.

                          TDA2003 is a 10W car radio audio amplifier The device provides a high output current capability (up to 3.5A) very low harmonic and cross-over distortion. Completely safe operation is guaranteed due to protection against DC and AC short circuit between all pins and ground,thermal over-range,load dump voltage surge up to 40V

Step 1: Things Required

Picture of Things Required

lists of components required to build the circuit


  • R1:220 Ω
  • R2: 2.2Ω
  • R3: 1Ω 1 watt
  • Rx: 39Ω                                  See the datasheet paw to alter the value of Rx
  • RV1: 10kΩ


  • C1: 2.2µF 25V electrolytic
  • C2:470µF 35V electrolytic
  • C3:0.1µF polyester or ceramic
  • C4:1000µF/35 V electrolytic
  • C5: 100nF polyester or ceramic
  • C6: 100µF 35v electrolytic
  • Cx 39nF                                       See the datasheet paw to alter the value of Cx


  • IC1: TDA2003
         :  connectors (cream shell connectors )
3-  2 pin connectors

mario19993 months ago

Hi, I have made this project but have a question.When I plug my amplifier with music I can hear some scratching noise.Could that be from Cx which I put 33nf instead of 39nf? Thank you for interesting design and helping with my first breadboard project.

usbg3rd (author)  mario19991 month ago

Happened to me at the start .. there can be three possible reasons for this ..

Either the audio input is not connected to anything .. i.e. its
floating .. possibly touching the floor it could cause this problem.
(using a battery should solve this problem but still make sure that the
circuit's ground is not directly in contact with the floor)

2- Either the connections are loose in ur PCB/Bread-board.
3- kindly check that ur power supply does not have any noise too (use a filter if yes).

lgnoni9 months ago

Good day sir, congrats for your project, it's something easy, powerfull and very elastic! buuutt, it was working for me ,but then, yesterday, i just attached it to the power supply (atx power supply, 12v, and also tried with 17v and worked really well!) but when i attached it, my tda 2003 started to ''smoke'' i thought it was the C4, but when i attached again, nothing happened, and it was working fine,so i thought that some wire where touching something... i hot glued almost everything that could touch something, and worked well, i just attached it again and while working the tda started to smoke and i saw a bit of fire also :O now ,when i attach the power supply it work for some second ... what do you think about it? why my TDA started to burn? too much Ma maybe? :O or just i may need some heatsink?

usbg3rd (author)  lgnoni9 months ago

Good day to you too .. and thanks, m glad u liked it :)

I need to be clear on some things before i can give u a right guess.
you were using the same supply before but yesterday it caught fire right ?

and Is there an Ampere knob on your power supply ?

plus you should definitely use a heat sink with TDA Ic's its recommended for long life of the IC ..

lgnoni usbg3rd9 months ago

Hi sir, thank you! you're so kind :) anyway, i use a commond atx power supply, so i can have 12v with 16a, and 17v with maybe 13a or so around. but i was just thinking that amperes aren't a problem since the ic's use how many amperes he need, not more! so, i just wired a diode to see if it's a polarity problem since my tda caught on fire at the vcc pin.... i don't think it's a heatsink problem, anyway, i'm using it too, i just bought a tda2030 too, so i want to try it, what do you think about it? :) also, i bought 10 tda2003 for just 1 euro from hong kong, so i can replace it when i need! :D thank you sir, see you:)

usbg3rd (author)  lgnoni9 months ago

Actually in voltage supplies the amperes are not a problem but in supplies that are voltage and current both they have problems ... because the amplifier suddenly draws a lot of current when a high beat is being played so the power supply switches it self to current supply and if the current supply is set to a greater value than the max current which is 3A it will burn the IC. i have not tried TDA2030 instead i have tried here is the link


and no problem :) see you..

If I can add something, When you have a Bigger Heatsink you can get about triple Amperage on the circuit, but try to stay low on it.

usbg3rd (author)  KévinG141 month ago

Havent tried it. but seems logical.

bunzix8 months ago

Hi, I'm having a problem with the circuit and i was wondering if you could hep me. Every time I plug in the power supply it generates a loud hum which cannot be controlled by the potentiometer. I checked everything four times and there's nothing wrong with the connections. And it's not from the power supply, I used a battery also.

usbg3rd (author)  bunzix8 months ago

Happened to me at the start .. there can be two possible reasons for this ..

1- Either the audio input is not connected to anything .. i.e. its floating .. possibly touching the floor it could cause this problem. (using a battery should solve this problem but still make sure that the circuit's ground is not directly in contact with the floor)

2- Either the connections are loose in ur PCB/Bread-board.

bunzix usbg3rd8 months ago
Well, I fixed the hum problem by replacing a capacitor from the power supply with 3 capacitors that together have 3200uf, but now i get i constant popping sound. And i can't hear anything from the sound source.
usbg3rd (author)  bunzix8 months ago

verify that the IC gets the audio input and power supply voltage use a DMM/ oscilloscope to monitor it ... if all is fine try replacing the IC ... IC normally gets damaged while soldering .. so use an IC bed for plugging in the IC and its better as in-case the IC's burns out due to some reason u can just pull it out and replace with a new one :)

bunzix usbg3rd8 months ago

Thanks for help, i managed to fix that also and it started to hum again(faulty ground i suppose). I also swapped the ic with a new one but it was the same in both cases, the hum and the popping sound...and i used an ic bed from the very first time i soldered the components.

good day sir, is it okay to use a power supply with 18 volts, 3 amps full bridge rectified.?

usbg3rd (author)  johnrey.valenzuela.510 months ago

good day to u too :) yes a supply with 18v 3A bridge rectifier should work perfectly .. just in case try with a lowest volume and increase it to the maximum slowly ... and if u hear some fluctuation noises from the supply then shut it down immediately .. it wont happen but taking a precaution is good for you, your amp and your supply :)

thank you sir, for answering my question. more powers and project sir. this is so helpful.

usbg3rd (author)  johnrey.valenzuela.510 months ago

my pleasure :) .. and haven't been able to do something in a while... will upload one real soon .. and thank u .. favourite/share/follow :)

What type of socket is the tda2003 plugged into?

usbg3rd (author)  rusty.shackelford133711 months ago

its the Pentawatt package. i dont know if such type of ic-bed exists so i broke an ic-bed and used it for placing my ic in the circuit ...

u can direct solder if u are good at it ... the purpose was that just in case if the IC burns out then i can instantaneously change it without desoldering and then resoldring a new one .

can you tell me how loud this amplifier can be? and the voltage output

usbg3rd (author)  marionddgzmn1 year ago

loudness is 10w in layman terms its 2x as laptop usb speakers
and voltage output ? what do u mean by it ? it depends on the signal what will the output be.

Soldat71 year ago

Ah the TDA2003. i love this amplifier. Currently in the process to track down proper capacitors for it while designing a PCB for it. Ive experimented a little with the Cx value and learned a little about how capacitor types can influence it. 39nF-ish (most go for either 47n or 33n) is ok for testing, but it can sound a little shrill at times in actual sound as its too low to do its actual job of cutting down the top end in any noticable way(even lets high-frequency noise trough negating its purpose). If you replace it by something a bit bigger (say a 4.7uf cap) the higher trebles get rolled of. which can give a warmer sound it seems. In the end the vallue is open to experimentation. Ive seen 470uf caps getting used as the Cx so its quite safe to try stuff out.

That is what i enjoy the most out of this amplifier. you can toy around with it quite easilly and modify its output in noticable ways.

Oh and ive toyed around with C4 a bit. Its purpose is mostly to remove any leftover DC element from a AC signal (Class AB amps tend to have a bit of a DC offset which speakers don't like as it can cause them to burn-trough). A smaller C4 causes the bass to diminish. However increasing the vallue (say 2200uf) causes the bass to be increased.

usbg3rd (author)  Soldat71 year ago

I havent tried it yet . the value worked fine for me. but thanks for sharing what purpose it serves. i hope BASS lovers will like it :)

It mostly depends on the speaker size. If a big speaker (like the one you used) is used a big capacitor is probably best. Surprisingly however is that its not the vallue that can have the biggest influence, but the brand. i ordered myself a bunch of those large "Audio" caps used in high-quality stuff just to see how noticable the effect is.

Thank you for inspiring me to get into audio amplifiers (this was the instructable that got me to try the TDA2003 rather then stick with the LM38x series). I'm even tempted to make a sort of follow-up instructable that goes a little more in-depth into how to finetune the amplifier and to reduce noise. By now ive altered nearly every vallue in the circuit with some interesting effects ^^

usbg3rd (author)  Soldat71 year ago

well m glad :) thank u , fav , vote :)

the 39nF is difficult to find in our place. can i use other value than that? what could you suggest? if possible in micro nor pico.
usbg3rd (author)  jeuphatos jr.1 year ago

Haven't tried that personally , cant say for sure , but probably a large value wont disturb the circuit but a lower value will. it will not cause your circuit to blow up so give it a shot, see what are the results.

if it works do tell me.

you can also check if the sound quality is UN-acceptable with a different value of Cx then use combination of capacitors (probably in series) to get the required value. :)

thanks for your comment , like and follow :)

I got the exact value you provide but when I made the pcb based on your pcb design you provide..... my capacitor 6 is exploding..... any thoughts?

is the wattage of all resistor 1/2?
usbg3rd (author)  jeuphatos jr.1 year ago

R3 which is 1 Ohm is 1 Watt. make sure it is 1 watt else it might heat up and break their circuit. for the rest of the resistors u can use 1/2 or 1/4 watt resistors.

usbg3rd (author)  jeuphatos jr.1 year ago

what is the input voltage ? are u sure u are connecting the right terminals of capacitor , because electrolytic Capacitors explode when either the voltage is higher than their rating or the capacitor is connected in opposite polarity.

the layout in page 3 is what i mean.

You have R3 rated at 1W. Will .25W be sufficient for the remaining resistors?

usbg3rd (author)  charliemyers1 year ago
Yup charlie myers R3 is 1Watt as the resistor has a low value so more amount of current flows throught it and therefore the resistor might get damaged so we use 1 Watt resistor. and the remaining are .25 Watt resistors :) thanks for ur comment.
like and follow :)
pikku-ukko1 year ago
Can I use 50V capacitors for c1 c2 c4 and c5? The store I'm pretty much forced to use atm doesn't have any with smaller voltage.

Forgotten everything about electronics, going to be my first project in about 10 years:D
usbg3rd (author)  pikku-ukko1 year ago
dude, u can use any capacitor with voltage greater than 25V, BUT make sure the capacitance is same as mentioned otherwise the sound might be affected. the voltage rating only means that the capacitor can hold this much voltage across its end and therefore a higher voltage then required will only increase the price of the capacitor slightly :) thanks for ur comment , like and subscribe :)
yaly1 year ago
in the bill of materials you said that R2 = 2.2 ohm while in the schematic diagram R2 = 1 ohm, I build the circuit before noticing this, used R2 as 1 ohm and it sounded great, which value for R2 is correct ?
usbg3rd (author)  yaly1 year ago
actually its is 2.2 ohm but to find a resistor exactly is very difficult as they come in specific values ... so the nearest value i could get was 1 ohm ... and it worked for me too ...
yaly usbg3rd1 year ago
use two 1ohm resistors in series to have a total resistance of 2 ohms, that is the closest I can be !
usbg3rd (author)  yaly1 year ago
lol :P yeah ..
so do you mean i would do it just as shown in the schematic (with the 1 uf cap and 2k2 resistor) but instead of using 9v battery i could use one 1.5v cell?
usbg3rd (author)  Lacrossanator12 years ago
yes but mind that there are different types of mic so pick wisely and do not pic pizzo
the one i used i dont know the exact name or number but it was like
yaly usbg3rd1 year ago
that type of configuration in step 5 is for a type of mics called condenser mic as opposed to dynamic mics which include the piezo/peizo (not pizzo) and these (dynamic) work by generating a voltage on its terminals relative to the sound it receives, while the condenser mics can be said to act as a variable capacitor that changes value with sound, if you are going to use a dynamic mic then connect it directly to the input and gnd of the circuit and dismiss the battery, resistor and capacitor.
usbg3rd (author)  yaly1 year ago
thanks Yaly , Dynamic mic is nice to use ..
usbg3rd (author) 2 years ago
1- first that yes the value should be 44 ohm but u don't get exact valued resistors the nearest value available in the market is 39 ohms .. u can try different combinations (series or parallel ) if u want..
2- c2 c4 c5 cx must be greater than 35V it is because in case if they are not then the output sound might be distorted at high volume .. so its better u use 35 V .. actually it should be greater than the supply voltage so .. suit your self
yaly2 years ago
c4 doesn't reduce the bass as it blocks frequencies from below 20Hz, as humans can't hear them so its not a problem, but it also has to be there to block DC from entering the speaker and so damaging it, you may need to change its value to block below about 10-15Hz if you are using it for a subwoofer
usbg3rd (author)  yaly2 years ago
actually when we talk about BASS its very low frequency therefore capacitor also blocks the low frequency signals . and yes it also blocks the DC to protect the speaker
can a TDA2030av work???
usbg3rd (author)  golddigger15592 years ago
can't say for sure because this circuit is designed for TDA2003. but its circuit looks pretty similar , may be the components values are a bit different u can check the values from the datasheet.
I was just wondering if in the microphone add on circuit, is that two 9v batteries in series for a total of 18V? or just the one 9v battery?
usbg3rd (author)  Lacrossanator12 years ago
boy actually the microphone works on 1.5 or maximum i think 3 volts (depends on mic) and its power consumption is very very low .so u can use 1.5v cells they last so long in case of mic . so no need to build extra circuit to divert power to mic to .. but still u can do it if u like .
SaurIMX3 years ago
you can use transistors too without using the TDA2003
usbg3rd (author)  SaurIMX3 years ago
Making a amplifier with discrete components is the best punishment for anyone =P..
its too dificult to manage all of the transistors and even then all u get is a 1w or max 4w gain ..
if u have any link to discrete amplifier with gain greater than 10W do tell me i want to try one in summer.
2n3055 amplifier :O
usbg3rd (author)  qwerty1563 years ago
i have seen people making circuit from discrete components but when u will build one u will know that its more than 10 transformers that make up one amplifier 2 for the current mirrors 4 for the active loaded differential amplifier this completes one stage then comes the other stage which contains 2 transistors for the current mirror and 2 for providing bulk of gain so it is a HELL difficult making one discrete component amplifier and still u get 2W RMS output with consumption of 12V or greater
usbg3rd (author)  usbg3rd3 years ago
BTW Kid keep on trying for making a discrete one it is an achievement and making amplifiers with ic's Even a Technition can do that an Engineer builds with discrete components
kondzio293 years ago
You should try the TDA1554Q amp 2x22W stereo
only four partsin circuit ;D
usbg3rd (author)  kondzio293 years ago
Nice idea =)
but the IC works at 14V typically and delivers 44W output power which means that it will draw 3.2 Amperes current .. the transformers that are capable of supplying such amount of current are costly ..
B.T.W. it could be a very nice project for a music Lover ; )
why not use a computer power supply?
it will provide a lot of power on 12v
usbg3rd (author)  qwerty1563 years ago
U can use that just note that amplifiers do not draw continuous power so of the computer supply has some protection circuit it may stop giving power to the amplifier continually..
but still u can use that ... i will soon upload another supply circuit without transformer and rectifier circuit .. it will be quiet cheaper and efficient too..