At the back of my music keyboard's electric adaptor it says "INPUT: 230V, 50Hz 0.2A OUTPUT: 12V, 1.5A Suppose my adaptor busted and couldn't find the original replacement. Can I use a 9V instead? Will it work? Will it has to be 1.5A then? Power is=I^2 x R as well as I x V, does that mean as long as A value is 1.5A it justifies the formula and voltage is not important?? Will my device burn if I used -say- 24V ? How flexible I can be?