http://www.audiohobbyist.com/projects/smps.htm The next day I design a PCB with paralleled MOSFET so that I can drive it to around 150~200W without any problem. I'm stick with ETD29 layout footprint and I can have two version, either for SE or PP type with just the difference of 1 pair/ 2pairs of MOSFET and ETD29 / ETD34 core. The final board measures 10cm X 11cm X 3.5cm. After I had installed all the parts on it and test run it, the performance of this new PCB is bad. MOSFET runs hot and draws current nearly twice higher than the first prototype. I check the schematics and the problem is come from the snubber RC and narrow track width. I mistaken the 0.1 uf as 0.01 uF and harmonics everywhere on the PCB. After I change to 0.1uF the power supply and tin coated the high current track ,it runs happily and only slightly warm, driving a 100W bulb.