Thankyou very much for your help Hero.
The noise has already got low many times by using shielded cables and putting a sheet of foil, insulated by cardboard under the pcb.
The next time I make a pcb, I will surely consider your advices.
In my case I'm using aluminum foil connected to my ground, and paper sticker to fix it in the floor of my box where I put my circuit. it is doing fine.
Thankyou very much for your help Hero.
The noise has already got low many times by using shielded cables and putting a sheet of foil, insulated by cardboard under the pcb.
The next time I make a pcb, I will surely consider your advices.
Thanks. I also have seen the caps put across the rectifier in the supply os a cd player I ripped apart.
Please tell me how does it work? Doesn't the ac signal get into the dc supply through the caps?
Please explain me, just for knowledge.