Hello,
I've built k1803 preamp to run it with tda7375. I had to make it, because when I connect it to my mp3 it isn't loud, but with pc is ok. I just used NE5534, later I also tried LM748 in place of lm741. The problem is that it's making noise like old radio. I don't know why, I run it with 9V battery so it isn't ground loop problem, I tried to shield it, put 10nF between 4 and 7, nothing helped. Everything is connected as it should, it works, makes sound louder, but it makes unacceptable noise. Maybe this preamp isn't suitable to use it with tda7375, if so I hope you can suggest good, simple preamp with asymmetrical power supply that will work (make sound from mp3 louder without noise).
k1803: http://www.velleman.eu/downloads/0/illustrated/illustrated_assembly_manual_k1803_rev1.pdf
tda7375: http://www.classiccmp.org/rtellason/chipdata/tda7375.pdf
I've built k1803 preamp to run it with tda7375. I had to make it, because when I connect it to my mp3 it isn't loud, but with pc is ok. I just used NE5534, later I also tried LM748 in place of lm741. The problem is that it's making noise like old radio. I don't know why, I run it with 9V battery so it isn't ground loop problem, I tried to shield it, put 10nF between 4 and 7, nothing helped. Everything is connected as it should, it works, makes sound louder, but it makes unacceptable noise. Maybe this preamp isn't suitable to use it with tda7375, if so I hope you can suggest good, simple preamp with asymmetrical power supply that will work (make sound from mp3 louder without noise).
k1803: http://www.velleman.eu/downloads/0/illustrated/illustrated_assembly_manual_k1803_rev1.pdf
tda7375: http://www.classiccmp.org/rtellason/chipdata/tda7375.pdf