To avoid interference from magnetic fields, try to keep the sensitive input and signal wires far away from the power supply wires, speaker output wires, transformer, AC mains wires, and rectifier diodes on the power supply. To minimize the loop area, the following wires should be tightly twist...
A Fly Back converter is less efficient than a Buck Converter because all the output current needs to go through the Schottky diode which has a forward voltage drop that dissipates power. Also a real transformer coupling coefficient K, is always less than 1 due to magnetic flux leakage. The ...