Quote Originally Posted by deeaa
...but the frequency must be correct (50).
Just to make a little correction, the Frequency only matters with devices that use the 50Hz/cps or the 60Hz/cps for timing, frequency, or speed. It does not matter if the device is just converting voltage from AC to DC. So for a power adaptor for pedals won't care what the frequency is, just that the voltage is correct (the pedals don't care either, they run on DC voltage, so there is no frequency).

For example, an Amp does not care what the frequency of the power it is plugged into is, it only cares if the voltage is correct. A clock, however, does care what the frequency is, because it uses it to maintain the correct speed (it also cares that the voltage is correct as well).