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

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

<p>Hello, I made this with my own pcb design according to your schematics, <br>with EAGLE. I soldered everything right and supplied 12V from an ATX <br>PSU. Nothing happened even though I input sound from a mp3 player. But <br>when I turned the variable res, the 'Rx' resistor (39Ohm) began to smoke<br> and burned out. The IC was heated a little bit (I think it was usual). <br>Then I replaced the Rx with a 33Ohm as I didn't have more 39Ohm. But it <br>stayed perfectly without heating or smoking. Still it doesn't work. But <br>when I touch the input wires, it outputs a big 'DRRRRRRRRR' sound. What <br>should I do? I used a mp3player, mobile phone, laptop to input and test <br>it. same result...</p>
<p>Hi, I had this issue once. kindly check your volume control POT , C1 and ground . if any of these is faulty you wont be able to hear anything. as far as the the resistor issue is concerend its value is 39Ohm not 390Ohm so use 39 ohm resistor or anything close to 39.. What I suspect from the &quot;DRRR&quot; sound the issue is with your ground terminal it does not connect the IC's ground to Mp3 players ground ..</p>
thanks for your quick reply...<br>I found that I had soldered c1 reversed polarity. I corrected it. But the issue is same. Also I could realize that the 220ohm res was getting too hot. The pot works fine... How could I check the ground as you told above? Is my pcb the error? Or maybe the IC had blown out? <br>When I first turn the circuit on and touch the input wire with my hand, I hear the drrrrrrr sound. But after a few time, It also didn't work.... The issue is same...
<p>No problem, see this image the GND terminals marked as &quot;red Circles&quot; make sure they are connected to the -ive terminal of the battery/supply (in short do a continuity test for all the GND but make sure u do it on the marked ones because they are must) even if this doesn't work try shorting the pins marked 2 and 3 of the potentiometer. marked in &quot;blue circle&quot;. Its pretty normal for these IC's to blow up so make sure u don't solder it to the board instead use a connector like I did so that whenever it blows up just replace a new one. plus some people do mess up while they are soldering the IC to the board. one more thing use a heat sink with the IC too. its better.</p>
<p>Thanks for ur reply, but I could not get it to work. Can you pls send me the ready to etch pcb file (as an image in order to use toner transfer method), because I do not have proteus to open that file u have provided above. Maybe my pcb design is wrong... I'll give ur pcb design a try... Thanks</p>
<p>First here is the link to proteus: </p><p><a href="http://www.labcenter.com/download/prodemo_download.cfm" rel="nofollow">http://www.labcenter.com/download/prodemo_download...</a><br>its very easy as compared to any other simulator/PCB designer. It has a trial period so you dont have to buy it for some time and there are cracks available (which i dont support).<br>Second here are the files as per your request </p>
<p>hi , if i connect a mic as a input to this amplifier and connecting a speaker to this amplifier as an output , can i hear my voice from that speaker ...!? </p>
yea, you will. It will be just like a loudspeaker :)
<p>can i use the mic circuit with tda2050 amp ...</p>
<p>Hi Abbas yes you can use it with any amplifier its totally generic.</p>
<p>can i add bluetooth to it.?</p>
<p>Hi Kavish laxkar, yes you can add a bluetooth to it.</p>
<p>how and wat colud be the circuit.?</p>
<p>just google an audio bluetooth receiver .. here is how u can disasseble one .. </p><p><a href="http://www.instructables.com/id/STREAM-MUSIC-VIA-Bluetooth-on-any-amplifiers/" rel="nofollow">http://www.instructables.com/id/STREAM-MUSIC-VIA-B...</a><br>the place where he connected the audio pin can be connected to the audio input of the amplifier and there you go :) wireless portable amp :) </p>
<p>i have hc-05...can it br used.?</p>
<p>I googled it and most of the people say that it is used for serial communication and audio stream conversion is not included in it </p><p><a href="http://www.instructables.com/answers/Can-an-HC-05-Bluetooth-module-be-used-as-an-audio-/" rel="nofollow">http://www.instructables.com/answers/Can-an-HC-05-...</a><br>however if u use arduino and do the serialization urself (which wil cost u more than a new bluetooth that supports audio) it can be done.</p>
<p>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.</p>
<p>Happened to me at the start .. there can be three possible reasons for this .. </p><p>1- <br> Either the audio input is not connected to anything .. i.e. its <br>floating .. possibly touching the floor it could cause this problem. <br>(using a battery should solve this problem but still make sure that the <br>circuit's ground is not directly in contact with the floor)</p><p>2- Either the connections are loose in ur PCB/Bread-board.<br>3- kindly check that ur power supply does not have any noise too (use a filter if yes).</p>
<p>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? </p>
<p>Good day to you too .. and thanks, m glad u liked it :) </p><p>I need to be clear on some things before i can give u a right guess.<br>you were using the same supply before but yesterday it caught fire right ? </p><p>and Is there an Ampere knob on your power supply ?</p><p>plus you should definitely use a heat sink with TDA Ic's its recommended for long life of the IC .. </p>
<p>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:)</p>
<p>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 </p><p><a href="http://www.instructables.com/id/32W-Stereo-Audio-Amplifier/" rel="nofollow">http://www.instructables.com/id/32W-Stereo-Audio-A...</a></p><p>and no problem :) see you..</p>
<p>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.</p>
<p>Havent tried it. but seems logical.</p>
<p>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. </p>
<p>Happened to me at the start .. there can be two possible reasons for this .. </p><p>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)</p><p>2- Either the connections are loose in ur PCB/Bread-board.</p>
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.
<p>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 :) </p>
<p>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.</p>
<p>good day sir, is it okay to use a power supply with 18 volts, 3 amps full bridge rectified.?</p>
<p>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 :) </p>
<p>thank you sir, for answering my question. more powers and project sir. this is so helpful.</p>
<p>my pleasure :) .. and haven't been able to do something in a while... will upload one real soon .. and thank u .. favourite/share/follow :)</p>
<p>What type of socket is the tda2003 plugged into?</p>
<p>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 ... </p><p>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 .</p>
<p>can you tell me how loud this amplifier can be? and the voltage output</p>
<p>loudness is 10w in layman terms its 2x as laptop usb speakers <br>and voltage output ? what do u mean by it ? it depends on the signal what will the output be.</p>
<p>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.</p><p>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.</p>
<p>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.</p>
<p>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 :)</p>
<p>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 &quot;Audio&quot; caps used in high-quality stuff just to see how noticable the effect is.</p><p>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 ^^</p>
<p>well m glad :) thank u , fav , vote :) </p>
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.
<p>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.</p><p>if it works do tell me.</p><p>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. :) </p><p>thanks for your comment , like and follow :)</p>
<p>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?</p>
is the wattage of all resistor 1/2?
<p>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.</p>
<p>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. </p>
<p>the layout in page 3 is what i mean.</p>

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