After reading your posts and rethinking my project I decided not use the TDA7265, I want to do decent amplifier for a computer, I'd like to avoid the power supply but then I'd have to feed it with +12V.
My tests with TDA7265 have all gone wrong and I understand nothing about its behaviour I can only think the chip its damaged it seems to be in some sort of short circuit (or perhaps it's oscillating even with the capacitors soldered to chips legs).
So I changed to TDA 2030, I made exactly the circuit in the datasheet
http://www.st.com/stonline/books/pdf/docs/1458.pdf and it worked beautifully well from the start. With a portable CD player and my big loudspeakers I get quite good sound.
Now the problem: when I put a connecting wire to the computer it starts to hum loudly, in fact it gets all the noise when a wire is connected to the + input, no matter which power supply I use (transformer or switching power supply from the computer).
I imagine this problem is very easy to solve but have no idea how to: input cable disconnected, or connected to the computer: big hum, input cable connected to the portable CD player: absolute silence or music when playing.
I show you a pic of the new amplifier connected, yes the cabinet in the pic is the computer, you can see it here:
**broken link removed**, I made that small loudspeaker for the comp, it sound much better computer loudspeakers do.
Thank you for your help