I was thinking about using a stk chip amplifier for my car . I have a kenwood unit and I am planning to make an amplifier for the subwoofers . I already have a pcbs for a 100w dual channel stk which can also be bridged . I would like someone to help me out with the power supply designs . I require +40 -40v . my friend has already done a power supply ,but he has used an inverter ,but instead of 220v ,he has +30 -30v a.c at the outputs . The only hitch was that he used a normal iron core transformer than a ferrite core . could any of you help me with the circuit . I have acess to a pcb factory and ,if anyone else is interested I could also make a few more pcbs.