Audio distortion in Tba820 amplifier

Thread Starter

Anirvan

Joined Sep 21, 2019
6
I constructed a small audio amplifier for personal use using Tba820 ic according to the datasheet but when I increase the volume to maximum , the sound clips and distorts a lot. I play music from my android phone and my phone volume is also set to maximum. What can I do to prevent Clipping or distortion ?
 

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Dodgydave

Joined Jun 22, 2012
8,383
Firstly turn your mobile volume to Half, what supply voltage are you using and what speaker resistance have you got,

Ideally you want 12V supply on a 8 Ohms speaker, for max 2W power,
 
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BobTPH

Joined Jun 5, 2013
2,021
The output from your cell is designed to drive headphones, not an amplifier. At full volume it will be too high and cause the amp to distort.

Bob
 

Thread Starter

Anirvan

Joined Sep 21, 2019
6
So,
The output from your cell is designed to drive headphones, not an amplifier. At full volume it will be too high and cause the amp to distort.

Bob
So, what should be done to play with mobile phone output without distortion even if it's volume is turned all the way up ?
 

Thread Starter

Anirvan

Joined Sep 21, 2019
6
I'm using 9
Firstly turn your mobile volume to Half, what supply voltage are you using and what speaker resistance have you got,

Ideally you want 12V supply on a 8 Ohms speaker, for max 2W power,
I'm using 9Volt supply and 8-ohms 10 Watts rated speaker. I don't know if it can really handle 10 Watts but atleast it can handle upto 5 watts. Since this amp Tba820 is only 1.2 Watts amp so there shouldn't be any problem with the speaker I'M using.
 

Thread Starter

Anirvan

Joined Sep 21, 2019
6
Hello all!!
I'm a electronics lover and keep making circuits. I'm specially taking interest in making audio amplifier circuits these days, basically the chip amps. But I am facing a same problem with them and that's Distortion or Clipping of audio. I don't have much knowledge about the inside architecture of the audio chips nor I know about the term 'Impedence' used in the datasheets of these chips but I guess it has something to do with Distortion or Clipping. I want to know how to have a clean loud audio output without distortion even if the input is turned up to maximum accidentally ?
I made amplifier circuits with a few amp chips like Tda2003, Tda6283, LA4440, Tba820 etc according to datasheet but in all case if I increase the volume to maximum, there's distortion
 

bertus

Joined Apr 5, 2008
20,048
Hello,

Wich TBA820 version do you use?
There is the 8 pins TBA820M and the 14 pins TBA820.
The TBA820M is capable of 1.2 Watts.
The TBA820 is capable of 2 Watts.

Bertus
 

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bertus

Joined Apr 5, 2008
20,048
Hello,

What resistor value are you using for Rf?
That resistor determines the gain of the circuit.

Bertus
 

Audioguru

Joined Dec 20, 2007
11,251
The TBA820M amplifier IC is obsolete and has not been made for many years.

You said you want it to be loud. Then you need a 30W to 300W amplifier, not a puny 1W. 10 times the output power sounds twice as loud.
You also said you want maximum volume but no distortion. Then turn down the volume to where there is no clipping distortion.

All amplifiers produce clipping distortion if the volume control is turned up too high.
 
More supply voltage will help. And consider using a more sensitive (efficient) speaker. Or, use an amp chip that can be bridged, which means you'll need 2 amp chips per speaker, but will give you about 4 times the watts. Or just buy a class-D amp board from China; those can deliver 10 real clean RMS watts with a 12V supply, for the price of a hamburger. TA2024, YDA138, YDA148, TPA3110, TPA3116 are some examples of class-D amp chips.
 
Look carefully at the datasheet - the MIN Po possible is 0.9 W, so you could have a 'runt'

Then look at all the audio power ratings - they are given at 10% THD
Figure 4 (https://www.mycomkits.com/reference/TBA820.pdf) says you get just 0.8W (at 9V) for distortion under 0.5%

So as a hi-fi amp it SUCKS

Like others have stated there are issues with speaker efficiency and impedance matching but the primary reason is that;
it is a lousy amp for your purpose

Give it away and get an amp whose specs you have carefully reviewed and that has some muscle
 
Look carefully at the datasheet - the MIN Po possible is 0.9 W, so you could have a 'runt'

Then look at all the audio power ratings - they are given at 10% THD
Figure 4 (https://www.mycomkits.com/reference/TBA820.pdf) says you get just 0.8W (at 9V) for distortion under 0.5%

So as a hi-fi amp it SUCKS

Like others have stated there are issues with speaker efficiency and impedance matching but the primary reason is that;
it is a lousy amp for your purpose

Give it away and get an amp whose specs you have carefully reviewed and that has some muscle
Hello
From the datasheet with a 120 ohm resistor for R1 the input level is 60mV and the output of the phone is at least 20X that amount, so you will definitely get distortion. the solution is to put in a volume control to the amp and fix it so that at maximum level from the phone the audio is clean.
AFAIK the drive circuit and speaker of a cell phone is quite complex and the audio level is perceived to be quite loud, so you might not get much of an improvement from the amp with a 9V battery. the speaker you are using is also overated use a smaller speaker. the extra mass of the coil and cone reduces the efficiency.
 
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DUFFER

Joined May 3, 2013
11
As deep bahudoor said , replace R1 's with a dual pot of at least 10K and bring the output of the phone to the wipers via ~4.7 uF caps (negative to the wipers) and it could surprise you especially if you are using a proper speaker enclosure (miniature or not).
 

inOr

Joined May 31, 2017
4
Look carefully at the datasheet - the MIN Po possible is 0.9 W, so you could have a 'runt'
Then look at all the audio power ratings - they are given at 10% THD
Figure 4 (https://www.mycomkits.com/reference/TBA820.pdf) says you get just 0.8W (at 9V) for distortion under 0.5%

So as a hi-fi amp it SUCKS
I agree. I saw only one of those IC power amps with distortion specs I could tolerate. I forget which one it was. They work OK in cheap auto and boombox amps, but you shouldn't use them for a quality audio system. I suggest building an amp using discrete devices. There are plenty of schematics online and in books. I'm not impressed with the distortion specs of inexpensive class-D amps either. They are used because they are very efficient and small units can output high power, not because of their sonic qualities.
 
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