Introduction: 32W Stereo Audio Amplifier

Picture of 32W Stereo Audio Amplifier

special thanks to ALAMGIR NASIR

Who helped me make this project
                             The aim of the project was to make a stereo audio amplifier. in addition to this additional features should be that it should have volume control, bass control,treble control and left right control too.

                              For this project i used
1- Operational amplifier TDA2050 which is used in the main amplifier circuit
2- TDA1524 which is used in the pre-amplifier of the circuit.
3- I used the split DC power  ±22V as an external supply. The main advantage of the split supply over the single supply is that it is filtered from both sides (+) and (-) terminals and has the proper grounding system which are caused to decrease the output noise of amplifier but u can use single supply too.

Step 1: Pre-amplifier

Picture of Pre-amplifier

                            The arrangment shown in the diagram is the pre-amplifier.The circuit is designed as an active stereo-tone/volume control for car radios, TV receivers and mains-fed equipment.
It includes functions for bass and treble control, volume control with built-in contour (can be switched off) and balance.
All these functions can be controlled by d.c. voltages or by single linear potentiometers.

                             It starts from the input power supply integrated into the 3 pin is the positive voltage and negative voltage to pin 8. This circuit will have only R and C classes of devices to filter out frequencies in different area.When the signal from the sound source enters into the pin 15 of IC1, the INPUT signal is coupling through the C1 and C2 signals of each channel.
Left and the right, then the IC will amplify signals with C6 and C4. C5 and C3 act as base (low frequency control) with VR1-VR4 to adjust the Volume, Balance, Bass and Treble, respectively.

                  see the image for part list

Step 2: Main Amplifier

Picture of Main Amplifier

                               TheTDA2050 is intended for use as an audio
class AB audio amplifier. Thanks to its high power capability theTDA2050 is able to provide unto 35W true rms power into 4ohm load @ THD= 10%,VS =  ±18V,f=1KHz and up to 32W into 8ohm load @ THD=10%,VS = ±22V,f=1KHz. Moreover ,theTDA2050 delivers typically 50W music power into 4ohm load over 1sec at Vs= 22.5V,f=1KHz.

This is a power amplifier and requires 200mV RMS for full output. Voltage gain is 30.5dB with resistor values shown. Closed loop gain is set by Ratio R1/R2. Increase R2 for less gain and vice versa. Power bandwidth is 20Hz to 80KHz. R3, C3 and R6, C11 form a zobel network to prevent high frequency instability.

The speaker is direct coupled, therefore no expensive large value electrolytics are needed and the bass will be crisp and clean. It is advisable to place fuses in the power supply (not shown).

R1,R4,R5,R8______22k 1/4W Resistor
R2,R7__________680R 1/4W Resistor
R3,R6___________2.2R 1/4W Resistor
C1,C10___________1u NP 25V Capacitor
C2,C12__________22u 63V Electrolytic
C3,C11_________0.47u 400V Polyester
C4,C7,C8,C9_____100n 400V Polyester
C5,C6,C13,C14___220u 63V Electrolytic
U1,U2__________TDA2050V 32W Audio Power Amp

Step 3: Power Supply

Picture of Power Supply

you can take any 2 power supplies from the market they can be 20V each or a single that can supply +-20V ..

i am sorry about the power supply
because i  myself used two regular power supply from the lab and converted +22V to 12V for the pre-amplifier using lm7812 IC whic is simple to make.

the configuration below can help u making power supply

Step 4: Testing(video)

here is the video if some one likes to see . 100% working .

if u have any problems u can ,ail me at

and if u like this instructable please rate it  : )


tclayton (author)2017-03-11

Just a heads up to all who wanna build this, the tda2050 is a discontinued amp and if you try to order it online you may get fakes, i bought 10 of these and 6 so far were fake and didnt work at all. Id recommend the tda2003 as a replacement, theyre cheap, reliable, and have a low amount of external parts, ive used it many times with great success!

usbg3rd (author)tclayton2017-03-14

Thanks for giving the heads up, In my country they are easily available and mostly they are working, unless someone burns the IC while soldering.
and for the second part tda2003 has very less output power its around 10W i guess whereas tda2050 has 32W so it pretty much depends on the usability.

I have made an amplifier using tda2003 quite a while ago if someone is interested check out my other projects you will be able to find it there.

TeiglerP (author)2016-09-02

What it will be if i connect the -22 and the ground to make the negative side of the power supply , and the +22 side o the positive side? it will work?

usbg3rd (author)TeiglerP2016-09-03

I dont understand what are you trying to say so let me just tell what i think u are asking.
u will never touch -22 with ground or it will short circuit and your battery might get fire/damage. There is no such thing as voltage. its always a voltage difference (which means if I have a 22V battery/Supply it implies that the positive terminal of the battery is 22Volts higher than the negative terminal) so If you want to generate -22V All you need to do is connect the Positive terminal of your battery with the ground of the circuit (Ground is generally at 0 Volts so) your negative terminal gets 22V lower than it (0 - 22 = -22V). Its just a perception of it. I repeat there is no such thing as negative voltage.

Marc FlorenceC (author)2016-02-08

how much is the total cost of this amplifier?

usbg3rd (author)Marc FlorenceC2016-02-09

I dont remember exactly, its been a long time but as an estimate it was approximately 30$ (amp+ preamp)

AbbaR (author)2016-02-05

Hello. Can I ask if we can replace the pre amp circuit? Because the required ic is not available here. Thank you :)

usbg3rd (author)AbbaR2016-02-05

Hello. Yes you can replace the whole pre-amp circuit with any other pre-amp u want ... you can even ignore the pre-amp and just build the mail amp... pre-amp is just for tuning the sound.

AbbaR (author)usbg3rd2016-02-06

Thank you :D

MoinS2 (author)2016-01-31

how can i add the voice echo control in this, please guide?

usbg3rd (author)MoinS22016-02-01

The pre-amp TDA1524A does not suppot echo effect, as i mentioned before it only controls the volume, bass and treble. To gain echo effect some other pre-amp (audtio processor etc) can be used. I googled it and fount this IC

HT8972 Voice Echo

I havent seen it in detail but it will work .. just make sure the output of the ic is compatible with the input of the main AMP.

5PRO5KOMP5 (author)2016-01-24

Hi, Can I use only main amplifier for my speakers?

usbg3rd (author)5PRO5KOMP52016-02-01

Yes you can use the main amplifier without the pre-amp. the purpose of pre-amp is to change bass, treble and volume.

GrantC4 (author)2015-12-28


I cant open the:

TDA1524A tone control .rar

TDA1524A tone control 7.0 version.rar

files. what do they contain?


usbg3rd (author)GrantC42015-12-29

Hello, I just downloaded then and extracted them both are working fine. I am using winRar to extract these files. these files contain .lyt files (layout files) that can be opened in proteus.

GrantC4 (author)usbg3rd2016-01-04

where can i download proteus? becuase i cant seem to find it.

usbg3rd (author)GrantC42016-01-07

GrantC4 (author)usbg3rd2016-01-08

thanks :)

GrantC4 (author)usbg3rd2015-12-30

ok thanks, ya i can download it just not open it.

guess i don thave the right program to open it. im trying proteus now.

usbg3rd (author)GrantC42016-01-07

Good luck.

GrantC4 (author)GrantC42015-12-28

also, does the picture "parts list" contain all the parts necessary to build the whole instructable? or do all the other typed in parts list need to be added?

usbg3rd (author)GrantC42015-12-29

No the picture contains the part list for the pre-Amp and the partlist in text is for the main amplifier.

ainsworthl (author)2015-12-15

So the resistor to ground, should I place it before the 1uf capacitor where the signal enters the amp or should It be after the capacitor?

The reason why I asked is because in the schematic there is a 22k resistor going to ground after the 1uf capacitor.

usbg3rd (author)ainsworthl2015-12-18

It should be after the capacitor. make sure its connections are in good condition. i.e. they are properly connected to ground.

ainsworthl (author)usbg3rd2015-12-18

yes I already have a 22k resistor going to ground after the capacitor just like how it is in the schematic, or should I add another resistor?

usbg3rd (author)ainsworthl2015-12-20

No, personally i dont think that you should add any other resistor just verify the connections that the resistor is grounded properly ... or just test by shorting the terminal with the ground when the amplifier is running if the hum goes out it means there is a connection issue with the resistor. otherwise there might be an issue with the supply ... what type of supply are you using ? it should be pure DC. if you are using a supply with a transformer in it the signal is not pure DC and causes the amplifier to Hum. you can test this by using a DC battery instead of a supply ... if the hum goes out thats the issue if not then we can go in deep.

ainsworthl (author)2015-12-15

Oh and for the preamp I actually left out the pot for the balance control because I didnt think I would use it, do you think that thats what caused it not to output any signal

usbg3rd (author)ainsworthl2015-12-18

cant say for sure as i did use them and my works fine so it might be the issue.

ainsworthl (author)2015-12-12

can I build both sides of this amp and tie inputs together then tie outputs to make 64 watts stereo amp?

usbg3rd (author)ainsworthl2015-12-14

Haven't tried it not sure if it will work or not .. but it should i guess... but why risk it when u can even get a better IC of TDA series or some other IC to make Higher output power amps.

ainsworthl (author)usbg3rd2015-12-14

ok thats true, I built this amp and it works, when its not connected to my phone it makes noise when its connected there is a small hum but its not too bad can I get rid of that sound? Also I built the pre-amp but it doesn't work when I connect the signal to it and then the output to the amp I don't get any sound and I double check my wiring and it looks correct to me.

usbg3rd (author)ainsworthl2015-12-15

the noise might be due to the fact that the input of the amplifier is not grounded through a resistor. Using a resistor will remove the noise.The hum sound might be due to slight variations in the capacitors used or due to the power supply .. try using dc battery if the hum is removed than use capacitors to filter the input of power supply. Cant say about the pre-Amp it worked for me, you will have to debug it. try replacing the IC if needed.

Abbas arshad (author)2015-12-12

ok thanx...

usbg3rd (author)Abbas arshad2015-12-14

no problem :) rate if you like it.

Abbas arshad (author)2015-12-11

can i use mylar caps for all non polarized capacitors..with same values ..thanx for your reply...

usbg3rd (author)Abbas arshad2015-12-11

Mylar is one of the non-polarized capacitor therefore you can use one... each type has its own pro's and cons i hope it works for you.

Abbas arshad (author)2015-12-11

in main amp ..can i use two 10k resisters in series instead of using 22k ........

usbg3rd (author)Abbas arshad2015-12-11

You can use any combination of resistors but the equivalent resistance should be the same

Abbas arshad (author)2015-12-08

is switch 1 is vr1 's switch.....and tell me the types of capacitors u used in pre amp

usbg3rd (author)Abbas arshad2015-12-10

Types of capacitors , part list and every thing else is given in the figure in step1.

Abbas arshad (author)2015-12-08

whare is the part list for pre amp ( tone control circuit)

Shahriarr (author)2015-11-09

Can i use this pre-amplifire circuit with any main amplifire ? like LA4508 ic based amplifire

usbg3rd (author)Shahriarr2015-11-10

Yes you can use it with any amplifier its generic purpose. just make sure u give ur input to pre-amp and the pre-amp's output to the main amplifier not vice versa.

DuttA1 (author)2015-11-04

i will use in woofer that amplifier

usbg3rd (author)DuttA12015-11-05

yea, thats a nice idea .. I didnt had any spare so used a normal speaker.

aman.patnayak (author)2015-05-16

please send me the layout file of main amplifier..

usbg3rd (author)aman.patnayak2015-07-19

M sorry .. my Hard Disk failed recently and all data in it is gone ...
but u can find the pcb layout of the main amp in the datasheet of the
ic. and I used a lab-power supply for my amp. but still its pcb will
only take 5 mins .

nguyentienson121992 (author)2015-03-14

can you give me the pcb layout of main amplifier and power supply?

M sorry .. my Hard Disk failed recently and all data in it is gone ... but u can find the pcb layout of the main amp in the datasheet of the ic. and I used a lab-power supply for my amp. but still its pcb will only take 5 mins .

Spoonman192 (author)2015-01-26

The parts on your list do not correspond to the parts on the circuit diagrams, which is right, as I have bought the parts based on the parts list and when compared to the diagram they are wrong and/or unneeded?

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