I have a power supply (salvaged from a boom box) . The power supply works fine , and my output voltage is 9 volts D C . Without changing any of the components , can I change the connection of the secondary of the transformer , to get 18 volts D C as my output voltage ? The secondary of the transformer has taps which are not in present use . I think I can , but I do not know what it might do to the other components . Help please ! This may sound like a dumb question !