TDA2050 Amp Questions

[Abhijeet Jadhav]

I have 4 circuit of TDA2050. What will the single power supply ratings(voltage and ampere). capacitors are rated to 35v.

 

[audioguru]

The TDA2050 is obsolete and is not made anymore. All its details are in its datasheet that is available everywhere but I get it from www.datasheetarchive.com where you can select the manufacturer of a device. I do not know if there is a good or bad copy of it made in China.

The 330uF capacitors have low values too low to be the main power supply filters. Their 35V rating is good and is much higher than the absolute maximum allowed supply voltage of plus and minus 25V. The spec's in the datasheet are when it has a supply that is plus and minus 18V when its output at 1kHz with fairly low distortion is 28W into 4 ohms or 18W into 8 ohms. With an output of 28W into 4 ohms it heats with about 16W so the power supply must provide 28W + 16W= 44VA. The total supply voltage is 36V so the current should be a minimum of 1.22A. The IC will need a pretty big heatsink to dissipate 16W.

If your speaker is 8 ohms then you should have said so and you can calculate the lower current from the power supply yourself.

 

[Abhijeet Jadhav]

Special thanks to audioguru for fast reply and helpful info.
Ok, As per your info i have to use 36v,5amp single power supply for 4*TDA2050.

But I'm going to bulid custom transformer and i want to extract maximum power from it which can handle by that circuit.
So can i supply 50v5amp to 4 circuits (after changing onbord capacitors rated to 50v)

 

[DerStrom8]

Hello Abhijeet Jadhav, welcome to Electro-Tech-Online!

When you reply to someone else's thread asking about your own project, that is called "thread hijacking", which is not allowed here. It would have been much better to start your own thread, as your questions were about your own project.

I have moved your posts and Audioguru's response to your own thread. Please carry on the discussion here, and next time please start your own thread instead of asking your question on someone else's.

Regards,
Matt

 

[audioguru]

I assume that your speakers are 4 ohms since you need 1.2A of current for each amplifier? If your speakers are 8 ohms then the current is half.
I said that the 330uF capacitor values are too small, use 1000uF/35V. They do not need to be 50V since each one will have a maximum of half the total supply across it.

I NEVER operate an electronic part at its maximum allowed rating because it will probably fail too soon. Did you notice that the datasheet does not specify its power output nor its heating when it uses a 50V total supply?
With a plus and minus 18V supply its output into 4 ohms at 1kHz with fairly low distortion is 28W. If you extend the lines on the power graph in the datasheet to a supply of plus and minus 25V then its low distortion output into 4 ohms is about 46W.
Is 46W much louder than 28W? No, our hearing's sensitivity to loudness is logarithmic so 10 times the power sounds twice as loud so 46W sounds only a little louder than 28W. Some people might not notice the difference.

 

[Abhijeet Jadhav]

Hello Abhijeet Jadhav, welcome to Electro-Tech-Online!

When you reply to someone else's thread asking about your own project, that is called "thread hijacking", which is not allowed here. It would have been much better to start your own thread, as your questions were about your own project.

I have moved your posts and Audioguru's response to your own thread. Please carry on the discussion here, and next time please start your own thread instead of asking your question on someone else's.

Regards,
Matt

Sir sorry for that, i will take care next time.!

 

[Abhijeet Jadhav]

I assume that your speakers are 4 ohms since you need 1.2A of current for each amplifier? If your speakers are 8 ohms then the current is half.
I said that the 330uF capacitor values are too small, use 12000uF/35V. They do not need to be 50V since each one will have a maximum of half the total supply across it.

I NEVER operate an electronic part at its maximum allowed rating because it will probably fail too soon. Did you notice that the datasheet does not specify its power output nor its heating when it uses a 50V total supply?
With a plus and minus 18V supply its output into 4 ohms at 1kHz with fairly low distortion is 28W. If you extend the lines on the power graph in the datasheet to a supply of plus and minus 25V then its low distortion output into 4 ohms is about 46W.
Is 46W much louder than 28W? No, our hearing's sensitivity to loudness is logarithmic so 10 times the power sounds twice as loud so 46W sounds only a little louder than 28W. Some people might not notice the difference.

Thanks sir, again very helpful stuff.
Now i deside to use 0-36v 5amp.
But, really that i have to use 2*12000uF/circuit.??

 

[audioguru]

I have asked many times but you do not answer: What is the impedance of your speakers?? The impedance of the speakers determines how much power supply current you need and how much output power the amplifier/speaker will produce.
The speaker impedance also determines the value of the filter capacitors. I made a typo error on the value of the capacitors. They should be about 1000uF each.

 

[Abhijeet Jadhav]

I have asked many times but you do not answer: What is the impedance of your speakers?? The impedance of the speakers determines how much power supply current you need and how much output power the amplifier/speaker will produce.
The speaker impedance also determines the value of the filter capacitors. I made a typo error on the value of the capacitors. They should be about 1000uF each.

My speakers impedance is 4 ohms. Ooh thank god for suggesting 1000uF caps.
is there any advantage of using split power supply?

 

[Les Jones]

I do not think it is a good idea to run a device right on or above it's published maximum ratings. Using a 36 volt transformer the peak voltage will be about 51 volts. (36 x √2) When lightly loaded the transformer will give a slightly higher output than 36 volts RMS so you will probably exceed 50 volts DC output by quite a few volts even alowing for the 1.5 volts or so loss in the bridge rectifier. For use as an adio amplifier I don't think there is any advantage or disadvantage in using a split supply. With a split supply you would not need an output capacitor. (But you would need an extra capacitor in the power supply.) If you wanted it to work down to DC for example driving a servo motor then you would need to use a split supply.

Les.

 

[spec]

Just another point, by eliminating a big electrolytic capacitor in the audio path you will reduce distortion over the entire audio band, and, depending on your speakers, tighten up the the bass. In general, split supply amplifiers are superior to a single supply because of other advantages too. You would be wise to pay particular attention to decoupling, which should be shown in the application section of the chip's data sheet. I would recommend that you leave the local decoupling capacitors on the board as they are and put the big capacitors mentioned on the power supply. That way you will have the best of both worlds; low ripple voltage and good decoupling.

 

[audioguru]

Here is the difference between a split supply and a dual supply as shown in the datasheet. The 1000uF output capacitor value when there is a single supply cuts frequencies and reduces their resonance damping at and below 40Hz when the speaker is 4 ohms.

 

[Abhijeet Jadhav]

Is this circuit support split supply??
Or i have to do changes in it.!

This is mirror image of pcb

 

[Les Jones]

The design is for a split supply. (It does not have an output capacitor.) You need a power supply with an absolute maximum of + and - 25 volts with respect to ground. One thing that has not been mentioned is that the TDA2050 will need to be bolted to a heatsink. Note that if you do not use insulating washers (Which will increase the thermal resisrance.) between the heat sink and the TDA2050 then the heat sink will be sitting at -25 volts with respect to ground.

Les.

 

[Abhijeet Jadhav]

The design is for a split supply. (It does not have an output capacitor.) You need a power supply with an absolute maximum of + and - 25 volts with respect to ground. One thing that has not been mentioned is that the TDA2050 will need to be bolted to a heatsink. Note that if you do not use insulating washers (Which will increase the thermal resisrance.) between the heat sink and the TDA2050 then the heat sink will be sitting at -25 volts with respect to ground.

Les.

Thank you..!
Yes i will provide sufficient heat sink with a CPU fan for fast dissipation of heat.
And i will not connect ground to heat sink and anywhere to cabinet.

 

[Abhijeet Jadhav]

I found this simple split supply diagram.!
Plz can u revalue all caps

for 18-0-18 ac transformer.

There is one typo mistake in circuit diagram (+45 insted of-45)

 

[spec]

Thank you..!
Yes i will provide sufficient heat sink with a CPU fan for fast dissipation of heat.

A fan is not normally necessary. Also use a mica insulating washer between the amp case and the heat sink, with a thin layer of heat sink compound on both faces of the mica washer. Mica has the lowest thermal resistance out of the reasonably priced insulators.

 

[Abhijeet Jadhav]

A fan is not normally necessary. Also use a mica insulating washer between the amp case and the heat sink, with a thin layer of heat sink compound on both faces of the mica washer. Mica has the lowest thermal resistance out of the reasonably priced insulators.

i will not connect ground to heat sink and anywhere to cabinet.i will made a ground hub on stripboard.

 

[spec]

I found this simple split supply diagram.!
Plz can u revalue all capsView attachment 97303for 18-0-18 ac transformer.

There is one typo mistake in circuit diagram (+45 insted of-45)

I would be inclined to go for a 15V 0 15V transformer to give the amp an easier time especially as you are using a 4 Ohm loudspeaker. This will give you a voltage of (15* 1.414)-2 = 19V approx, . You can use a piece of aluminum as a heat sink, bolted to the amp case/chassis if that is made of aluminum. You will not damage the amp by overheating because it has built-in thermal protection. If you find that the amp is shutting down when played loud, just add some more aluminum.

 

[spec]

I found this simple split supply diagram.!
Plz can u revalue all capsView attachment 97303for 18-0-18 ac transformer.

There is one typo mistake in circuit diagram (+45 insted of-45)

The current cap values would be excellent- you can go as high as you like. It would be best not to go below 4m7F (4700 uF) though. The big capacitor is the reservoir and controls the power supply ripple voltage and the small capacitor is for high frequency decoupling.