TDA2003 AMPLIFIER

Thread Starter

dadadiouffy

Joined May 4, 2020
78
This amplifier is working but its overheating too much at 12v supply, then I use 5v supply, still its overheating but not that much, but so soon I switched it on

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the over-heating problems is caused by the 2.2Ohm and 1Ohm resistors which I used 10Ohm in their places or what that I cant figure out?
 

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Audioguru again

Joined Oct 21, 2019
2,690
Using the wrong resistor values causes the obsolete TDA2003 amplifier to oscillate at a very high frequency and get very hot.
Other problems:
Remove your 100k resistor at pin 1.
The capacitor at pin 1 should be 10uF.
The 39nF capacitor and 39 ohm resistor are missing.
Your 470uF capacitor should be at least 1000uF.
The speaker is supposed to be 4 ohms.
 

Thread Starter

dadadiouffy

Joined May 4, 2020
78
Using the wrong resistor values causes the obsolete TDA2003 amplifier to oscillate at a very high frequency and get very hot.
Other problems:
Remove your 100k resistor at pin 1.
The capacitor at pin 1 should be 10uF.
The 39nF capacitor and 39 ohm resistor are missing.
Your 470uF capacitor should be at least 1000uF.
The speaker is supposed to be 4 ohms.
I have combined some features from this schematic and the one I posted early, maybe something wrong with the speaker, protection for the speaker I wrongly soldered and 2.2R, 1R which replaced with 10R
 

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Audioguru again

Joined Oct 21, 2019
2,690
Why not look at the datasheet for the obsolete TDA2003?
1) It shows a MINIMUM supply of 8V.
2) It shows speakers 4 ohms and less.
3) It does not have your 100k resistor that will mess up its biasing.
4) It has a 39nF capacitor and a 39 ohm resistor to help prevent high frequency oscillation.
 

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schmitt trigger

Joined Jul 12, 2010
390
What Audioguru is trying to tell you, is that in these early power amplifier ICs, you must read and follow the datasheet recommendations.

Additionally, and I speak from painful personal experience, you *must follow* a star grounding scheme, which your breadboard clearly shows it does not.
 

MisterBill2

Joined Jan 23, 2018
8,005
IN ADDITION, the TDA2003 MUST have an adequate heat sink properly attached. That is in addition to following all of the other recommendations.
 

Audioguru again

Joined Oct 21, 2019
2,690
The IC will barely be warm when it has a 6V supply and an 8 ohm speaker. Its maximum output voltage will be 4Vp-p which is 1.41V RMS. Then the power in an 8 ohm speaker is only 0.25W if it works with the supply voltage less than its minimum of 8V.
Its heating will be about 0.12W plus its idle power of 0.24V for a total heating of 0.36W.
 

MisterBill2

Joined Jan 23, 2018
8,005
The IC will barely be warm when it has a 6V supply and an 8 ohm speaker. Its maximum output voltage will be 4Vp-p which is 1.41V RMS. Then the power in an 8 ohm speaker is only 0.25W if it works with the supply voltage less than its minimum of 8V.
Its heating will be about 0.12W plus its idle power of 0.24V for a total heating of 0.36W.
If the power were really only that small amount then why is the device put in a power-tab package instead of the much cheaper 8 pin Dip? And at 50% efficiency, with 250 mW out that says that a half watt may be dissipated.
 

Audioguru again

Joined Oct 21, 2019
2,690
If the power were really only that small amount then why is the device put in a power-tab package instead of the much cheaper 8 pin Dip? And at 50% efficiency, with 250 mW out that says that a half watt may be dissipated.
The power output number of an amplifier and its heating is Voltage times Current. If you double the voltage then the current almost doubles then the power and heating also increase almost 4 times.

The datasheet for the old TDA2003 says it was made for a car radio powered by 14.4V and driving a 4 ohm speaker. Then its output power was 6 Whats at high distortion or 4.8 Watts at low distortion. Then its heating was about 4W and it needed a power-tab package and a heatsink.

With the 14.4V car supply, the datasheet shows 10 Whats into 2 ohms. It also shows with a 17V supply, an output of 17 Whats into
1.6 ohms. Then the heating was very high. With a 17V supply, its idle current (not playing) was 46mA then its heating was 46mA x 17V= 0.78W.

An LM386 amplifier is in an 8 pin Dip because with a 9V supply and driving an 8 ohm speaker then its output power is 0.7 Whats or 0.56 Watts and its heating is 0.56W. Its maximum allowed heating is 1.25W.
 

Thread Starter

dadadiouffy

Joined May 4, 2020
78
The power output number of an amplifier and its heating is Voltage times Current. If you double the voltage then the current almost doubles then the power and heating also increase almost 4 times.

The datasheet for the old TDA2003 says it was made for a car radio powered by 14.4V and driving a 4 ohm speaker. Then its output power was 6 Whats at high distortion or 4.8 Watts at low distortion. Then its heating was about 4W and it needed a power-tab package and a heatsink.

With the 14.4V car supply, the datasheet shows 10 Whats into 2 ohms. It also shows with a 17V supply, an output of 17 Whats into
1.6 ohms. Then the heating was very high. With a 17V supply, its idle current (not playing) was 46mA then its heating was 46mA x 17V= 0.78W.

An LM386 amplifier is in an 8 pin Dip because with a 9V supply and driving an 8 ohm speaker then its output power is 0.7 Whats or 0.56 Watts and its heating is 0.56W. Its maximum allowed heating is 1.25W.
Thank you people for your help, my Amp is now working 100% very well. I run it for almost 4 hours without a heatsink but it was not heating up, but I will add a heatsink as well. The problem is only it cannot work well on small speak like 4Ohm 25W its distorting, with 8Ohm 300W its output is okay
 

MisterBill2

Joined Jan 23, 2018
8,005
Thank you people for your help, my Amp is now working 100% very well. I run it for almost 4 hours without a heatsink but it was not heating up, but I will add a heatsink as well. The problem is only it cannot work well on small speak like 4Ohm 25W its distorting, with 8Ohm 300W its output is okay
I am quite impressed by this performance. Is there any way you can post the amplifier circuit and let us know the voltages of the power supply? That could be a very useful circuit to use for some of my applications.
 

Audioguru again

Joined Oct 21, 2019
2,690
Any half-decent speaker rated at 25W pays perfectly with low distortion when fed low distortion audio at 25W. Your TDA2003 amplifier produced much less power than 25W.

The maximum output current and power supply current are doubled when an 8 ohm speaker is replaced by a 4 ohm speaker. Maybe you powered the amplifier with a weak little 9V battery that could not provide enough current when the speaker was 4 ohms.
 

AnalogKid

Joined Aug 1, 2013
8,946
Another thing about almost all audio power amplifier chips, especially older designs like this one: they are critically dependent on the power supply decoupling. Schematic #5 has no decoupling capacitors. This is a critical error.

In schematic #1, C1 and C2 must be as close as possible to pins 3 and 5. C1 should be closest, and both caps should have the shortest possible leads. Yes, 1" of wire here or there actually matters.

ak
 

Thread Starter

dadadiouffy

Joined May 4, 2020
78
Any half-decent speaker rated at 25W pays perfectly with low distortion when fed low distortion audio at 25W. Your TDA2003 amplifier produced much less power than 25W.

The maximum output current and power supply current are doubled when an 8 ohm speaker is replaced by a 4 ohm speaker. Maybe you powered the amplifier with a weak little 9V battery that could not provide enough current when the speaker was 4 ohms.
I used 5v supply from the main
 

Thread Starter

dadadiouffy

Joined May 4, 2020
78
Any half-decent speaker rated at 25W pays perfectly with low distortion when fed low distortion audio at 25W. Your TDA2003 amplifier produced much less power than 25W.

The maximum output current and power supply current are doubled when an 8 ohm speaker is replaced by a 4 ohm speaker. Maybe you powered the amplifier with a weak little 9V battery that could not provide enough current when the speaker was 4 ohms.
I will post the schematic diagram
 

Audioguru again

Joined Oct 21, 2019
2,690
5V supply? The TDA2003 has a minimum supply of 8V because some of them or all of them do not work with less voltage.
The datasheet shows the maximum output power dropping as the supply voltage drops and at 6V I calculated an output power of only 0.25W into 8 ohms if it works. With your 5V I doubt it works.
 

Thread Starter

dadadiouffy

Joined May 4, 2020
78
5V supply? The TDA2003 has a minimum supply of 8V because some of them or all of them do not work with less voltage.
The datasheet shows the maximum output power dropping as the supply voltage drops and at 6V I calculated an output power of only 0.25W into 8 ohms if it works. With your 5V I doubt it works.
thats why it was distorting, causes of underpowering I hope
 
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