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Bridge problem!


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Hi Mukhalled,
Attach the schematic of your bridged TDA2005 for us to see what is wrong with it.

The only difference on the datasheets between the TDA2005M (for a bridged amp) and the TDA2005S (for a stereo amp) is that the TDA2005M is selected for a max output offset voltage of 150mV. Then it will have a max DC current in a 3.2 ohm speaker of 150mV/3.2 ohms= 47mA without a signal which also creates heat. The TDA2005S doesn't have an output offset voltage spec so it could be too high for a bridged amp.

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Hi Mukhalled,
Attach the schematic of your bridged TDA2005 for us to see what is wrong with it.

The only difference on the datasheets between the TDA2005M (for a bridged amp) and the TDA2005S (for a stereo amp) is that the TDA2005M is selected for a max output offset voltage of 150mV. Then it will have a max DC current in a 3.2 ohm speaker of 150mV/3.2 ohms= 47mA without a signal which also creates heat. The TDA2005S doesn't have an output offset voltage spec so it could be too high for a bridged amp.


Hi Mr. Audioguru,

I was waiting for your answer

post-3826-1427914290482_thumb.jpg

tda2005.pdf

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Your very fuzzy schematic is a copy of the one in the datasheet so it should work. It would be clearer if you saved it at a GIF or PNG file type. You saved it as a huge JPG file type which is used for photographs.
The polarity of the electrolytic capacitors are shown with the solid bar as the negative end.

What is your exact supply voltage?
What is the voltage at pin 8 and pin 10?
What is the speaker's impedance?

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Ok, I've attached it again and i hope it's clearer now...

Thanks. It is much clearer and uses many fewer bytes.

the supply voltage i use is 9V.

Its minimum supply voltage is 8.0V and it uses a very high current at full output. If your supply is a little 9V battery then it won't work.

What is the DC voltage at pin 8 and at pin 10?
What is the impedance of the speaker?
What is the level of the input signal?
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It is oscillating at a low frequency.
I think it has way too much voltage between outputs because it isn't the IC selected for being a bridged amp which would have a very low voltage between outputs. The voltage between its outputs causes a high supply current which might reduce the supply voltage enough that the amplifier doesn't draw so much current so the supply voltage rises. Then it does it over and over.
It might work fine if the supply voltage doesn't change by its current. A regulated supply or a direct connection to a charged car battery.

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The only difference on the datasheet is the matching of the pin 8 and pin 10 voltages for the TDA2005M for a bridged IC. Your TDA2005S doesn't have the voltages matched causing  them to be 1.6V different.

Maybe the 1.6V difference is causing the IC to heat then shut-down for a moment before cooling then working again, over and over.

Did you use the pcb layout on the datasheet? If you didn't then maybe the IC oscillates at a very high frequency which makes it hot, shuts down then cools and works again, over and over.

The heatsink is too small if the IC gets hot enough to shut-down.

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The board you show is poor for a high current amplifier. Years ago I made a similar amplifier with Veroboard and it worked well. Maybe my wiring layout was lucky.

Tantalum capacitors have poor reliability and cause audio distortion when used as coupling capacitors. Electrolytic capacitors are better for audio but film capacitors are best. Since 2.2uF film capacitors are huge and expensive, use electrolytics.

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