TDA2822M Amplifier Audio Output is Cracking, Please Help !

[Razor2]

330nF is 0.33uF which is marked "334" in Asia. It should be available anywhere.
An Asian "474" capacitor is 470nF or 0.47uF and can be used instead.


C3 in the datasheet is a very importannt Supply Bypass Capacitor that keeps the IC from oscillating. It DOES NOT PASS AUDIO.
Your circuit has it missing.
C5 in your circuit passes audio to the input of the amplifier and since your input resistor is 10k then the capacitor should be a film capacitor of about 330nF or 0.33uF or an Asian 334 greencap. An Asian 474 will also be fine.


The The two 4.7k mixer resistors and 330nF coupling capacitor connect to your 10k audio taper volume control.


All electronic circuits need a supply bypass capacitor that keeps the supply voltage from jumping up and down when the circuit uses current. It prevents an amplifier from oscillating.


10uF as an input coupling capacitor is way too much. it should be a 330nF film cap as I said before.
The 10uF capacitor can be used as the supply bypass capacitor.


Yes. 10uF is way too high. It can pass earthquake vibrations.


Its value is 30 times too high so it can pass frequencies as low as earthquake vibrations (1.8Hz). Audio goes only as low as 20Hz and the 330nF capacitor produces a 53Hz cutoff frequency into the 10k volume control parallel with the 100k input resistance of the IC which is fine.

If you use a 20k ohm volume control the the 330nF input coupling capacitor can produce a cutoff frequency of 29Hz.

Thank you very much for clearing my confusion, I'll change the circuit as you said & will report how it's working tomorrow.
Once again thanks !

 

[Razor2]

I redesigned the circuit as you suggested.
Now the circuit is working for both my music player & laptop but the lower frequencies are distorting, what to do ?

 

[audioguru]

Distortion from an amplifier is usually when its output is "clipping" when you turn up the volume too high then it cannot produce the loudness that you want. This is an amplifier with a puny output power so turn down the volume then it does not distort.
Your amplifier also might be oscillating at a high frequency that causes distortion.

My car radio had a 128W (real Watts) amplifier for the sub-woofer and it could play as loud as I wanted with no distortion.
Your bridged amplifier has an output into an 8 ohm speaker of only about 0.75W like a cheap clock radio when the supply is 5V.

EDIT: I wonder why there is a big space here?

 

[Razor2]

Distortion from an amplifier is usually when its output is "clipping" when you turn up the volume too high then it cannot produce the loudness that you want. This is an amplifier with a puny output power so turn down the volume then it does not distort.
Your amplifier also might be oscillating at a high frequency that causes distortion.

My car radio had a 128W (real Watts) amplifier for the sub-woofer and it could play as loud as I wanted with no distortion.
Your bridged amplifier has an output into an 8 ohm speaker of only about 0.75W like a cheap clock radio when the supply is 5V.

EDIT: I wonder why there is a big space here?

actually i know that the amp. can amplify the signal upto certain level, further increasing the volume will just distort the audio, so i keep the volume at that level & its enough for my needs.
But the problem is diff.
i can clearly hear the distortion when i lowers the volume down
also at max volume level(the level i described above) i can hear distortion while playing some music !

 

[audioguru]

I can clearly hear the distortion when I lower the volume down.

The TDA2822M is not hifi so its distortion at low level is 0.12% and is 0.25% at clipping that some people can hear.

The LM3886 IC is hifi and its distortion is only 0.03% at low levels and is 0.1% at clipping.

 

[Razor2]

The TDA2822M is not hifi so its distortion at low level is 0.12% and is 0.25% at clipping that some people can hear.

The LM3886 IC is hifi and its distortion is only 0.03% at low levels and is 0.1% at clipping.

Thanks for all the help ! amp is up & running well.

One question
will it be better to add output capacitors to this circuit ( i have 470uf & 1000uf )
if so then please tell me where to connect them & what will it do...
if not why...
View attachment 69146

waiting for your reply...

 

[audioguru]

will it be better to add output capacitors to this circuit ( i have 470uf & 1000uf )
if so then please tell me where to connect them & what will it do...
if not why...

Output capacitors are not needed because pin 1 and pin 3 of the amplifier IC have exactly the same DC voltages (half the supply voltage).
An output capacitor is needed if a speaker is connected to ground with this circuit that has a single polarity supply voltage.

Your input capacitor C5 is 10uF so it passes frequencies as low as 1.6Hz! It should not have polarity because each end has zero VDC.
If you want the capacitor to cut bass frequencies then it could be a 0.1uF film capacitor to cut frequencies below 160Hz.
Or completely remove C5 and R1. The volume control will serve as R1. The music source will cut very low frequencies.

 

[Razor2]

Output capacitors are not needed because pin 1 and pin 3 of the amplifier IC have exactly the same DC voltages (half the supply voltage).
An output capacitor is needed if a speaker is connected to ground with this circuit that has a single polarity supply voltage.

Your input capacitor C5 is 10uF so it passes frequencies as low as 1.6Hz! It should not have polarity because each end has zero VDC.
If you want the capacitor to cut bass frequencies then it could be a 0.1uF film capacitor to cut frequencies below 160Hz.
Or completely remove C5 and R1. The volume control will serve as R1. The music source will cut very low frequencies.

the diagram i showed was just to remind you of the circuit
otherwise i made the circuit as you said earlier :
stereo to mono mixer circuit using to 4.7k connected directly to c5 - 470nf film
R1 - replaced by 10k vol control
added bypass capacitor 10uf between Vs & gnd

amp is running good, but recently i found that when i play some music containing huge bass, increasing the volume a little starts distorting the audio
while playing normal music i can get much higher volume
thats why i asked above question

 

[audioguru]

amp is running good, but recently i found that when i play some music containing huge bass, increasing the volume a little starts distorting the audio. While playing normal music i can get much higher volume.

What do you expect from this very low power amplifier? Its maximum output power before severe distortion is tiny. If you turn up the volume too high then of course it distorts the loudest sounds.

 

[Razor2]

What do you expect from this very low power amplifier? Its maximum output power before severe distortion is tiny. If you turn up the volume too high then of course it distorts the loudest sounds.

Yes, but i don't expect much as I want it to be as portable as possible.
can you suggest, how to enclose (box) the speaker to get the most out of it ?

 

[audioguru]

An 8 inches diameter woofer produces low frequencies pretty well. Its datasheet will have a sealed enclosure and a ported enclosure designs that are recommended.

A dome tweeter produces high frequencies pretty well. Its datasheet will have a recommended crossover type and frequency.

I made a good sounding speaker with a 5" woofer and a dome tweeter but its sealed enclosure is too big to be portable.

My computer speakers have 3" full range speakers with rubber surrounds and huge magnets and they sound pretty good. Each enclosure is about 1 litre.

 

[4pyros]

can you suggest, how to enclose (box) the speaker to get the most out of it ?

A speaker enclosure should be designed around the speakers specifications to get the most out of it.
Do you have any specs on your speakers?

 

[audioguru]

CHEEP cluck cluck CHEAPO speakers do not have specs.
They sound awful.

EDIT: Some people are deaf to sound quality.

 

[4pyros]

In that case you can put them in any box and thay will sound just as bad.
But if we even knew the size of the speakers, then we could guess at a box size.

 

[Razor2]

@audioguru & 4pyros
It's a 3 inch 8 ohm 1.5 watt full range speaker
& ya it doesn't have any specifications

 

[4pyros]

@audioguru & 4pyros
It's a 3 inch 8 ohm 1.5 watt full range speaker
& ya it doesn't have any specifications

You will have to use trial and error to find what soulds best if you have no specs.
Start with a small ported box.
You could put it in just about anything and it will still sound just as bad.
Seems to me you would be better off buying a set of computer speakers.

 

[audioguru]

Here is one of the best 3 inch speakers. It costs $34.65US. It is rated for 5W continuous power, is 8 ohms and resonates at 165Hz.
In a pretty big 6L bass-reflex enclosure it still does not produce deep bass sounds.

The frequency response curve is with the speaker mounted in an infinite baffle (a huge sealed enclosure) so that the resonance frequency is not increased.

 

[Razor2]

Sorry, it's been a long time but i need one suggestion

I'm making an ac - dc power supply for this amp
how much current(max) this little amp could draw to give its best ?

In Bridge connection
Supply 6V
Load 8ohm

Accordingly i'll buy the transformer of required current rating

Thanks

 

[audioguru]

I'm making an ac - dc power supply for this amp
how much current(max) this little amp could draw to give its best ?

In Bridge connection
Supply 6V
Load 8ohm

Its datasheet shows an output at clipping of only 0.9W into 8 ohms with a 6V supply and it dissipaters 1W of heat. so the total load on the power supply is 1.9W maximum FOR ONE CHANNEL. To produce 6VDC using a full wave bridge rectifier, the transformer must have a voltage of 6VAC.

If you play at full blast the transformer must produce 1.9W/6V= 317mA.