How to Make a Simple Stereo Audio Amplifier Circuit Using IC 1521

A simple stereo audio amplifier circuit discussed here is built around the IC TDA 1521, requires very few external passive components and is able to provide a powerful 12 + 12 watts of music output.
The IC contains all the built in features required for an amplifier circuit like automatic mute, overload and over heat protections.

The circuit of a stereo audio amplifier using IC TDA 1521 presented here is very simple to build, utilizes very few external components and yet is able to produce 12 + 12 watts of hi-fi music power. The input can be from a CD player or your cell phone

Building a stereo audio amplifier usually refers to using two mono amplifiers and integrating their inputs, common ground and the supply to get the required stereo provisions. However such circuits generally tend to become too bulky and moreover making identical modules simply makes everything double and thus the costs involved also get doubled. But there are quite a few single chips available in the market which contains built-in dual amplifier blocks to make things really compact and sleek. One such IC is the TDA1521 which is a dual high fidelity power amplifier chip embedded inside a 9-pin plastic encapsulation. The chip is perfectly suited to be used with rough power supplies and indeed has rugged specifications. We will discuss how to make a simple stereo amplifier using this IC, but before that let’s first go through some interesting specifications of this device.

The TDA1521 basically produces optimum performance with dual supply voltages of around 16 volts and will deliver a good 2 × 12 watts of music thrust into a couple of 8 Ohms loud speakers.

The gain of the amplifier is internally calibrated and fixed at 30 dB with a space of 0.2 dB. This ensures a nice balance of gain in between its two channels.

The chip carries a special in-built music mute facility. The feature enables the IC to disconnect its non-inverting inputs when the supply falls below +/- 6 volts, although the amplifier remains successfully biased at this voltage.

The above property makes the circuit free from unnecessary clicking noises while switching the circuit ON and OFF.

The output of the IC is well protected against overloads and accidental short circuits. The IC also includes a thermal runaway protection so that excessive heating of the IC will not damage it; however it may shut-off at high case temperatures. Therefore it is recommended that the IC is fixed with a heatsink rated at 4K/W when the output is subjected to a 8 Ohm load @ +/- 16 volts supply.

Please note that the pin #5 of the IC is internally linked with the external metal tab over the IC.

Specifications

The following data provides a few interesting specifications accompanied with this stereo amplifier chip:

Total Harmonic Distortion: 0.5% @ 12 watts,

Quiscent Current Drain is less than 40 mA,

Gain Balance is around 0.2 dB,

Supply Ripple Rejection is around 60 dB,

Channel Separation is @ 70 dB,

Output Offset Voltage is 20 mV,

Power Bandwidth (@3 dB) is 20 to 20000 Hz.

Circuit Description:
The circuit shown is quite simple and is almost self explanatory. As you can see this stereo audio amplifier hardly requires any components to become a full fledged stereo amplifier. Just a resistor/ capacitor network to handle frequency compensation and a couple of input DC blocking capacitors is all that is needed to generate high quality stereo music from this little package….amazing indeed. The whole unit of this stereo audio amplifier can be easily built over a general purpose board and the whole system along with the power supply may be enclosed inside a sturdy metallic box. Whether it’s your CD player or your cell phone, it will convert every bit of it into a heart throbbing true pulsating stereo output.

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60 comments

comments
December 28, 2011 at 8:50 PM delete

hello sir i am glad to meet you here. i have been redirected here from bright hub.i appreciate you for the special circuit request.coming to my problem, i am studying in a college far from my home. it takes 2 hours to go to college by college bus and again 2 hours to come to home.i am feeling bored of traveling. in the bus we wanted to listen music. but volume from the cell phone is not audible to everyone. so i made a amplifier circuit using ic lm386.but the sound clarity and the volume is low.it is producing some other sounds. i want a circuit which gives more volume better clarity and works at 12v or below. i read about the ic tda 1521, but they are not available in our area. so kindly send me a circuit which consists of regular ic's. or even by using transistors which works at 12v or below. thank you

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December 28, 2011 at 9:56 PM delete

Thank you Harish, Welcome to my Blogspot.

I'll surely try to find out a suitable amplifier circuit for you and publish it here soon.
I'll inform you once it done.

Regards.

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January 9, 2012 at 9:48 PM delete

Hi Harish,

Please inquire whether the IC 810 or IC TDA2003 are available in your area or not, because I'll be writing an article on one of these ICs.

Reply me if any one of these are available, so that I can provide you with the circuit information.

Regards.

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January 12, 2012 at 7:35 PM delete

thank you for your fast reply. none of these ic's are available in electronic shops.IC ul2003 is available in our area.i'll try to find this ic 810 or tda2003 in tv and amplifiers shop.
regards.

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January 13, 2012 at 8:30 AM delete

OK, I'll wait for your reply.
Regards

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January 17, 2012 at 7:15 PM delete

sorry for the late reply.i bought the IC tda2003.hope you would make the circuit quickly.
with regards.

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January 18, 2012 at 8:28 AM delete

Hi Harish,

I'll publish the related article by today itself.
Regards.

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January 18, 2012 at 12:50 PM delete

Hi Harish,

For the time being, you may refer the following article, if possible go ahead and make the circuit:

http://www.brighthub.com/engineering/electrical/articles/81276.aspx

Regards.

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January 22, 2012 at 11:19 AM delete

if the article is published please inform me. I will be thankful to you.

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January 22, 2012 at 12:41 PM delete

Hi Harish,
Did you go through the link which I gave you? It contains all the information required to build an amplifier using IC TDA2003.

I'll write the related article on a separate blog which will include only amplifiers, but it may take quite sometime until it appears.

Regards.

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January 24, 2012 at 9:34 PM delete

Yes i gone through the link and made the circuit. But i think the sound is low when connected to a 9v battery. Can you publish the circuit which gives more sound and good quality of sound with this ic TDA2003.

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January 24, 2012 at 9:49 PM delete

No circuit can work if the required amount of power is not supplied to it, after all the power in the speaker will depend on how much power you provide to the IC.
A 9V PP3 battery will never be able to drive any circuit, therefore you will need to increase the power input.
Use small SMF battery 9 to 12V 1AH for powering the circuit and in order to get desired level of output.
Regards.

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February 4, 2012 at 4:49 PM delete

Hai sir .. I am very much interested in assembling circuits but my friends telling it is not possible .. Is it possible for beginners to assemble there circuits.. What will be the average cost?

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February 4, 2012 at 5:27 PM delete

Hi Neil,
Who told you this?...they are ignorant.
It does not cost much to procure basic electronic components.
In India it's very cheap, you can assemble any small electronic project at costs less than Rs 50/-that's $1.
However, learn the basics first before moving toward practical stuff.
Regards.

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February 4, 2012 at 7:33 PM delete

Thank you sir ..
I have done course in mobile service and 5.1 hometheatre assembling is that enough basics. Can i have your mail or facebook id for asking doubts,. Please

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February 4, 2012 at 9:01 PM delete

Hi Neil,
If you know how to understand and use the basic electronic components then it's enough, probably you should have learned them by now...
You can correspond in the blog here, our conversation will help to enlighten the other folks also who would be reading the articles...

Regards.

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April 11, 2012 at 3:24 AM delete

Hie there
these have really been a help, am looking forward to assembling my own amplifier and i hope the information provided here will be of great. help thanks

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April 12, 2012 at 7:54 PM delete

i need help..
I bought a sony dvd player .. It has only coaxial output for 5.1audio.. I asked in shop they told to buy amplifier for 5000rs but i already own a home theatre.. I need any assembled pcb or circuit to convert coaxial to analogue.. Please .. Reply

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April 12, 2012 at 9:42 PM delete

Please refer the article given in the following link, if possible build it for your application:

http://sound.westhost.com/project85.htm

Regards.

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May 14, 2012 at 9:46 AM delete

hai.. Again..
I still didnt find any coaxial circuit or pcb ..

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May 14, 2012 at 9:47 AM delete

also i can we increase the channel separation.. Is there any circuits for that.. Please help

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May 14, 2012 at 10:20 AM delete

Hi Neil,

I think the circuit can be easily built over a piece of veroboard, because there's hardly any components involved.

Not sure about a channel separation circuit, I'll to try to find out, though.

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October 9, 2012 at 1:20 AM delete

hello sir,
my name is naval singh, and i want to assemble a high quality and high power amplifier for my room, that can give crisp and super clear audio quality(high bass and treble), please suggest me any circuit diagram.
i will be greatly thankful to you.

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October 9, 2012 at 2:45 PM delete

Hello Naval,

You may try the circuit shown in the following link, I have tested it it's wonderful.

http://www.eeweb.com/project/circuit_projects/300-watt-mosfet-real-hi-fi-power-amplifier

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Anonymous
October 30, 2012 at 4:58 AM delete

Is it possible to use an TEA2025B ic?

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October 30, 2012 at 3:36 PM delete

It will provide only 2 watt output

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November 7, 2012 at 10:42 PM delete

thank u very much sir. and sorry for the late reply as my exams were going on.

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guru
November 16, 2012 at 8:53 PM delete

hello friend..
i have a 12v 1Amp transformer and few lm324 and 1c 741 with me. i would like to do a audio amplifier of my can u help me with a circuit using above components.
thanking u in advance

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November 17, 2012 at 8:46 AM delete

Only with opamps you won't be able to make an amplifier, you will have to add output transistors also for it.

You may refer the first circuit in the following link:

http://homemadecircuitsandschematics.blogspot.in/2011/12/how-to-build-electronic-spy-bug-circuit.html

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guru
November 17, 2012 at 7:38 PM delete

hey, thank u dude.
but that circuit is four small speakers and for head phones.
i have 4 50w speakers. could u pls guide me to make cheap stereo amplifier??

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November 17, 2012 at 8:33 PM delete

OK dude, then probably you will have to go for this circuit:

http://homemadecircuitsandschematics.blogspot.in/2012/04/how-to-make-simplest-100-watt-mosfet.html

741, 324 etc won't help much....

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May 9, 2013 at 11:32 PM delete

Dear friends i want to make an.audio amplifier at my home in.order to increase my knowledge about amplifier.....pls try to send a practically made amplifier diagram to my mail id mukeshthakur55@gmail.
Thanks & Regards
Mukesh Thakur

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May 9, 2013 at 11:37 PM delete

Dear sir please help me to make an audio amplifier for my mobile.......i want to make this because i want to increase my knowledge about amplifier....

..
Please enlist the components and homemade diagram of simple audio amplifire
Thanks & Regards
Mukesh Kumar

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May 10, 2013 at 12:18 PM delete

The design shown in the above article is the simplest and the best, you can try it.

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January 13, 2014 at 6:24 PM delete

good evening sir!!!
belated christmas and a happy new year!!

I have some doubts.
1. Do I need to use preamplifier before the amplifier?
2. Can I use 4w / 1.6 ohms Speaker?

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January 14, 2014 at 12:10 PM delete

wish you the same

1)no need of a preamp if the input is from a source such as a cellphone, DVD player, TV, Ipod etc.

2) did you mean 16 ohms? never heard of 4 watt 1.6 ohms speaker, anyway both can be used here.

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January 14, 2014 at 3:55 PM delete

thanks for the reply
no it says here:

Impedance: 4 ohms
Rated Input: 1.6 watts
made in japan
and its a casio product. A speaker from my mother's piano. :- )

I have another question.
1. Can I power the speaker (mentioned above) with 10 watts amplifier?

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January 15, 2014 at 10:49 AM delete

I think you should use a smaller amplifier with this speaker,10 watts could damage it, you can try a LM386 circuit for it.

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June 8, 2014 at 6:06 PM delete

Pls sir, help me with this questions:
1. Are all capacitor electrolytic?

2. Are those 100k presets?

3. Is there volume control in the circuit?

4. What is 10E and log dual.
Thanks alot.

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June 8, 2014 at 8:23 PM delete

1. the one which is between bridge is only electrolytic erst all are ceramic disc.

2. 100K are pots not presets.

3. the 100k pots are the volume controls.

4. 10E = 10 ohms, log is the specification of the pots.

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April 13, 2015 at 11:30 PM delete

hellow sir . i am new to electronics and i have been interested in amplifiers projects which they have been working well . But i have been facing problem of signal clipping mostly on small amplifiers such as tda 2822 even of higher such as tda2040 . how can i avoid this

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April 14, 2015 at 9:39 AM delete

Hello Joshua, are you sure it's signal clipping? Did you check it with an oscilloscope?

TDA2030 will not have this problem normally, please confirm the fault once again....

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August 19, 2015 at 5:57 PM delete

Hi sir i am new to electronics. We are asked to make a battery operated dual audio amplifier for MOBILE PHONES in OUR electronic project. The above circuit is fine except that it uses mains supply and a transformer. Please suggest a good circuit with ALL POSSIBLE DETAILS AS I AM NEW TO ALL THIS. Thanks in advance.

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August 20, 2015 at 3:53 PM delete

Hi Kanak,

you can operate the above circuit with a battery as well, however you will need two 12V batteries and connect them in series.

just remove the four diode bridge and the capacitor and the transformer and connect the battery as explained below:

The center series connection of the two batteries will join with the line which is marked with a "ground" symbol.

positive of the battrey will go to the pin7 of the IC and negative with pin5 of the battrey

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August 20, 2015 at 3:54 PM delete

...sorry it's pin5 of the IC ....not the battery.

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August 24, 2015 at 11:42 PM delete

How do i add bass and treble control in the circuit?

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August 25, 2015 at 12:12 PM delete

You can do it as explained here:

http://www.homemade-circuits.com/2012/01/how-to-make-your-own-active.html

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September 8, 2015 at 3:48 PM delete

Well thnx , but now we are given an amplifier circuit from the net. Its a 20w stereo amplifier using tda7377. They have also used an irf1405 mosfet .... but I dont know why it has been used. I am not getting the irf1405 mosfet anywhere in the market..... what should I do?? Is there any other mosfet which I can use over there? Can u tell me what is the mosfet used as..... a voltage regulator or linear amplifier? Is there any alternative?

Thanks in advance. Regards.

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September 8, 2015 at 7:54 PM delete

check the datasheet of the mosfet to find its voltage and current specs, any other mosfet with similar rating can be used as a replacement.

without seeing the diagram I won't be able to suggest much.

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January 4, 2016 at 10:01 PM delete

the Ic in this article uses ± 21 V maximum would that be 42 volts accross the 2 end termials and 21v from end to center? Or is it that ± 21V is 10.5v from end terminal to center?

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March 23, 2016 at 10:17 PM delete

is it possible to parallel transistors in this circuit I sent to get more power out say 600 watts, what would I need to do?

https://www.dropbox.com/s/epye1zn0c0hhkwu/200watt-anfi-devre-semasi.png?dl=0

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March 24, 2016 at 11:09 AM delete

the image is taking too long to open...

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March 24, 2016 at 8:04 PM delete

Ok sorry about that this is my google drive link

https://drive.google.com/file/d/0B0N-CQJdWSP0RXBIWHZpclRRVEk/view?usp=sharing

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March 25, 2016 at 7:51 AM delete

I am not sure whether the transistor can be paralleled in this circuit or not, normally transistors can be paralleled to increase power by using individual resistors at their bases, but in this deign I am not sure because of the IC in the middle.

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