I did try to power a 4 ohm woofer from a LM1875 circuit (it's the second circuit in the datasheet?) And it worked but not giving more than 3watts. Now I went into trying the first circuit in the datasheet but because it's a little bit complicated I did re-draw it and soldered the parts together. You can see in the pics below the schematic and compare it with the original one in the datasheet. First when I touch the pin which should be Vin, no noise is coming out. And secondly I'm a bit confused about where should I input the negative side of the power supply (12v lead acide) is it -Vee or just ground or both ? And where should I also connect the input signal
I appreciate your help

 

We're waiting for your pics.......

 

Here is the re-built shcematic

 

I was having some errors sorry for being late uploading the pic

 

Here is also the original one

 

You are confused because the first circuit requires two separate supply voltages.
It won't give you more power unless you add a second supply.

For a single supply you need to stay with the second circuit.
According to this:

you should be getting about 5W output into an 8Ω speaker with a single 12V supply.
You should be getting more than that into a 4Ω speaker but perhaps it is current limited at that supply voltage.

If you want more than that from your 12V supply then you need to go to a bridge output type of amplifier.
That will double the peak speaker voltage and give 4 times the power output (since power is proportional to V²).
There are a number of 12V audio power chips available with a bridge output, which are common for automotive applications.
Here's an example.

 

Now I've already built the first circuit. What should I do please ?

 

If you are going to run from a single power supply you should consider putting a large capacitor in series with the speaker, as shown in the second schematic in the datasheet. That will save you a lot of wasted power.

 

Now I've already built the first circuit. What should I do please ?

You could build another and use them in a bridge configuration (speaker connected between the two outputs).
For that you would also need a gain of -1 inverting op amp to invert the signal to one of the amp's inputs, so that one amp is pushing while the other is pulling.
For a bridge configuration you don't need the large output capacitor in series with the speaker.