A traditional "linear" power supply uses a transformer to convert the incoming voltage to the right level before rectifying it and distributing it to what ever needs it. This type of circuit is found in most "old" units that used valves or early transistor technology.
If you put the wrong voltage in you run the real risk of blowing up the input stages as too much current will be drawn.
In more recent times switching mode power supplies have become much more common. These rectify anything coming in and then do level conversion by some clever electronics to produce the required outputs. The advantage of this approach is that they can be run off a wide range of frequencies and voltages. Always check the input ratings on the unit.
One final note of warning. Some transformers (in fact all to a greater or lesser extent) are frequency sensitive, so even though you get a step up transformer to provide the correct 240v supply you might find that you get a strange buzzing noise from your 50Hz amplifier now struggling with 60Hz!!
If you put the wrong voltage in you run the real risk of blowing up the input stages as too much current will be drawn.
In more recent times switching mode power supplies have become much more common. These rectify anything coming in and then do level conversion by some clever electronics to produce the required outputs. The advantage of this approach is that they can be run off a wide range of frequencies and voltages. Always check the input ratings on the unit.
One final note of warning. Some transformers (in fact all to a greater or lesser extent) are frequency sensitive, so even though you get a step up transformer to provide the correct 240v supply you might find that you get a strange buzzing noise from your 50Hz amplifier now struggling with 60Hz!!