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I have built an audio amplifier circuit like the test circuit in this TDA2007A datasheet I am going to use this circuit with Raspberry Pi 3B+ and going to feed sound via 3.5mm of Raspberry Pi to this circuit.

I am using 2x3W 4Ohms speakers at the output of pin7 of the circuit (using like a mono.) I have not created another part of the circuit of pin1,9 and 2.

I have connected everything perfectly on the zero PCB and made it run but lots of noise is there on playing anything. So how can I remove those noises?

enter image description here

enter image description here

EDIT

Hi, I have tried the solution of Potentiometer it worked a little bit. The sound which is coming out still has noise. If I set Potentiometer at which the noise is not produced the output Sound is very Low on that. And If I increase the sound with the noise I can't hear anything at all.

Helpm me to solve it Please.

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  • \$\begingroup\$ What sort of noise? \$\endgroup\$ – HandyHowie Jun 21 at 7:48
  • \$\begingroup\$ you'll need to do a bit more debugging here; does the noise increase or decrease with volume? What about different frequencies of signals? The classical beginner error would be to underdimension the power supply. What's your power supply? Please also add a photo of the actual circuit you've built to the question. \$\endgroup\$ – Marcus Müller Jun 21 at 7:48
  • \$\begingroup\$ @MarcusMüller I have added the pictures of my circuit and I am providing a power supply of 10V. And using 2 3W 4ohms speakers. I don't have DSO or CRO or anything to check the signal. So if you can help regarding it. \$\endgroup\$ – El_Dorado Jun 21 at 9:51
  • \$\begingroup\$ One of your electrolytic capacitors in the centre of the board looks like neither of it's terminals are connected to anything. \$\endgroup\$ – HandyHowie Jun 21 at 9:56
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    \$\begingroup\$ Describe the noise. Buzz? Hum? Scratchy? White noise? Sonething else? \$\endgroup\$ – JRE Jun 25 at 8:37
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Lets start this by getting a picture of your circuit.

This is the "test circuit" from the datasheet:

enter image description here

From your description, you say there's noise there when you play something through the amplifier. That sounds to me like you are talking about distortion.

That happens (in the simplest case) when you have too much input signal for the amplifier.

See that little note by the title of the circuit (Gv= 36dB?) That says the circuit has a voltage gain of 36dB. That means if you put a 1V peak to peak signal on the input, then the amplifier will try to output a signal with 63V peak to peak. It can't do that, though, because you can't power the TDA2007A from a voltage source that would allow that much voltage swing - the TDA2007A can only operate on up to 26V, but you would need like 65V to get the full swing from a 1V peak to peak input.

The datasheet also says that the maximum input level is 300 millivolts RMS. That's less than 1V peak to peak. The input stage itself can't accept more than that.

The most likely cause of your problem is just that you are giving to too much of an input signal. Any device intended to drive an earphone directly will easily give you a 1V peak to peak signal.

The fix is fairly simple:

Reduce the input level.

Connect a 10k potentiometer to your amplifier as a volume control.

Like this:

enter image description here

Vin goes to your signal source, and the wire from the wiper (the arrow) goes to the input capacitor of your TDA2097A.

Set your audio source (mp3 player, phone, whatever) to the middle of its output range, then adjust the potentiometer so that the output doesn't sound distorted.


Now that you've posted a recording, I can tell that you aren't talking about distortion.

The noise in the recording comes from the processor in your Pi.

I think the simplest thing to do is to put a relatively low value resistor across the output of the Pi. Say, 100 ohms.

The "noise" makes its way into your amplifier by various ways, most of which will be fairly high impedance. A low impedance load will "short circuit" the noise from high impedance sources.

The other (simple) thing you can do is to use the potentiometer to turn the volume down until the amplifier output is clean, then turn up the volume on the source until it is loud enough.

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  • \$\begingroup\$ Ok, so potentiometer at where the 22uF cap is connected means on pin 5 because from there I am providing the input signal through audio jack cable. Not place it Vs right from where I am providing power supply, right? Just for confirmation. And this circuit isn't used for application purpose? \$\endgroup\$ – El_Dorado Jun 21 at 9:53
  • \$\begingroup\$ Connect the wiper of the potentiometer to the capacitor C1. The capacitor must be there, and the signal must go through the capacitor. \$\endgroup\$ – JRE Jun 21 at 10:07
  • \$\begingroup\$ Again for confirmation the capacitor symbol in the circuit: white side is positive and black side is negative right? \$\endgroup\$ – El_Dorado Jun 21 at 10:09
  • \$\begingroup\$ Plus is the white side. \$\endgroup\$ – JRE Jun 21 at 10:19
  • \$\begingroup\$ Thank you so much. I am right now adding the potentiometer to it. \$\endgroup\$ – El_Dorado Jun 21 at 10:20

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