I'm making an audio amplifier on 12v 5amp supply. But when I connect it with the power supply, the speakers are making some buzzing sound. It wont go high when increasing volume and won't decrease also. I connected my amp board with another supply of 1 amp and it doesn't have that problem. It was a f full bridge supply without centertap. I'm using a 12v dual 5amp supply. For this amp, I connected just *12v and 0. ( I didn't used the negative part) . So what is the problem and if I want to make another supply, which circuit should I use. Half Bridge rectifier with two diodes or full bridge with four diodes. I have a 12-0-12 5 amp transformer.
Post up a schematic of your circuit. But most likely, you are hearing mains hum. Which means that you have inadequate filter capacitors after the rectifier, or some other way of the unfiltered AC/DC leaking onto the final stage of the power supply. Could also be a board or wire layout issue. Posting pictures of all would help.