TDA2822M Amplifier Audio Output is Cracking, Please Help !

[Razor2]

I built the below circuit & was working fine.

View attachment 68543

But then I changed the output capacitors with 1000uf in order to get more bass frequencies & the problem started. Although the bass has increased but the sound is not clear, its distorting or cracking sound is coming out.

Then I reverted back the output capacitors to 100uf but still the same is happening.

Please help !

 

[transistor495]

You may double check all the wiring and find if any loose jonts. Post detailed clear double side view of the item. Before that clean the pcb tracks well to remove any solder balls especially at input pins.

 

[Razor2]

Thanks for the reply, I'll post em

Edit:

The distortion is going high when both the channels are being amplified
if i'm disconnecting a channel (left or right channel) the other plays fine with a less distortion & good bass quality

what should i replace in the above circuit in order to get some good quality bass for both channel simultaneously & stop the distortion ?

 

[crutschow]

I think the USB power, which is limited, may not be sufficient to power both channels. Can you try it with an external power supply?

 

[Razor2]

@crutschow
Yes I did tried with a 9v supply, but the same is happening
btw, currently the output capacitors are not 100uf but 1000uf(it gives a good quality bass but for a single channel only, connecting both the channels makes the distortion high with a very little bass)

 

[transistor495]

If everything is wired correctly then there shouldn't be any distortion, but a clean sound regardless of the value of the caps connected in the output.

You may also check whether ground connections are wired correctly, please check the attached image edited with 'red circle'. One ground connection goes to stereo input pin. These wiring issues can add distortion.

View attachment 68559

 

[Razor2]

@transistor495
The areas that you indicated, I checked em again but their correctly connected

 

[transistor495]

It is a good procedure to use DIP sockets for IC so that you can try replacing the chip with new one(if the chip is bad), and you can take them out to use for other projects later as well.

Also testing the whole thing on a breadboard fully before assembling is preferred so that you can attain the confidence for building.

There are alternative debugging procedures out like:-

*) Leave the USB , power it using a 6V battery.

*) Step by step method: Remove stereo pin and test the individual inputs using some other sources, and finally both simultaneously.

Next time post that you hit on success

 

[Razor2]

It is a good procedure to use DIP sockets for IC so that you can try replacing the chip with new one(if the chip is bad), and you can take them out to use for other projects later as well.

Also testing the whole thing on a breadboard fully before assembling is preferred so that you can attain the confidence for building.

There are alternative debugging procedures out like:-

*) Leave the USB , power it using a 6V battery.

*) Step by step method: Remove stereo pin and test the individual inputs using some other sources, and finally both simultaneously.

Next time post that you hit on success

Yes i did used socket for the IC
I'll try by replacing the IC & will soon report
is their any way of getting some good quality bass for both the channels

 

[Razor2]

I tried your debugging procedure

stereo source : Mobile
power : 9v battery

same result no change

 

[transistor495]

If nothing works then try with a new chip. Do not use 9V, use 3V -6V or 4 AA cells to power.

If you have a breadboard then try everything on that first. Do not fry the chip again by wrong/short connections.

Not sure what bass you're taking about this little USB powered amplifier. In this kind of projects bass almost depends on the speakers/drivers used. Cheap speakers means no bass at all. Also USB does not provide much current.

 

[Razor2]

If nothing works then try with a new chip. Do not use 9V, use 3V -6V or 4 AA cells to power.

If you have a breadboard then try everything on that first. Do not fry the chip again by wrong/short connections.

Not sure what bass you're taking about this little USB powered amplifier. In this kind of projects bass almost depends on the speakers/drivers used. Cheap speakers means no bass at all. Also USB does not provide much current.

Thanks !
So, should i keep the 1000uf capacitors(output) or revert back to 100uf ?

 

[picbits]

Use the USB to charge a set of rechargable batteries which in turn are used to power the amplifier.

A USB socket gives out 5v at aroudn 500mA so a maximum of 2.5W unless you have an out of spec USB port.

 

[transistor495]

Thanks !
So, should i keep the 1000uf capacitors(output) or revert back to 100uf ?

1000uF not needed, a 100/220/470uF are pretty OK.

Post any pic.

 

[ronv]

Does it sound better with the volume low??
If it does you might eliminate R1 and make C1 larger (1000 Ufd.)
If you use 470 Ufd. for the output caps the low frequency will be good to about 40 HZ.

 

[alec_t]

Yes I did tried with a 9v supply, but the same is happening

If the 9V battery is a little PP3 it's not surprising! You need a battery (or wall-wart supply) which can provide a lot of current if you want undistorted bass from both channels.

 

[Razor2]

Use the USB to charge a set of rechargable batteries which in turn are used to power the amplifier.

A USB socket gives out 5v at aroudn 500mA so a maximum of 2.5W unless you have an out of spec USB port.

1000uF not needed, a 100/220/470uF are pretty OK.

Post any pic.

Does it sound better with the volume low??
If it does you might eliminate R1 and make C1 larger (1000 Ufd.)
If you use 470 Ufd. for the output caps the low frequency will be good to about 40 HZ.

If the 9V battery is a little PP3 it's not surprising! You need a battery (or wall-wart supply) which can provide a lot of current if you want undistorted bass from both channels.

Thanks everyone for your help !

@alec_t
Yes, the 9v batt.. is pp3,
as I want to make the whole thing small enough to fit in my laptop bag

@ronv
case 1
as you said, i tried by removing the R1 & replacing C1 by 1000uf & output capacitors 470uf
Result - produced large amount of noise
case 2
connected the R1 again having C1 1000uf & output capacitors 470uf
using usb power supply - same thing happened, didn't work for both channel
using 9v batt.. - produced large amount of noise

so i reverted back the circuit

 

[ronv]

It is a simple enough circuit and as shown in your drawing should work. That is why everyone suspects your power supplies are not big enough for it to work with both channels.
Other things we don't know is what the assembly looks like. Sometimes if wires are to long and output wires are close to input wires that can cause problems.

 

[audioguru]

Get rid of the 1 ohm resistor. All it is doing is limiting the already very low maximum output power.

With a 5V supply and the 1 ohm resistor removed, each channel has an output at clipping of only 0.32W. Their total is 0.64W and the heating is about 0.8W so the total from the 5V power supply is 1.44W (288mA).

With a powerful 9V battery, the little IC will overheat. 6V is the maximum supply voltage shown on the datasheet when driving two 4 ohm speakers.

 

[transistor495]

I would say do not get rid of R1 from the circuit as it seems like a short circuit protection with USB compliance. If any other power supplies are used, then omit R1.