(I cant find any reference to voltage on the back or in the instructions, but a similar player on Amazon says its only 120V). What would happen if I plugged it in simply with a plug adapter? Would it blow up, short circuit, play CDs at lower speeds, etc?
It will blow up...... Or at best it will burn out, blow a fuse, and most likely take a few other internal components along with it as well. Don't even
think about trying it!
--My IBM laptop (dual-voltage)
If it's marked for 240V, it will be fine with a suitable plug adapter or replacement power cord.
--Sonic toothbrush (no idea about its voltage)
You need to check the device for the rating label which should tell you what voltage(s) it's designed for. If it's a fairly new cordless, battery model, then the charger may be multi-voltage -- see below.
--battery chargers for all my digital cameras (no idea about voltage, but they worked fine in the Middle East with nothing more than a plug adapter).
--AA rechargeable battery chargers (no idea, but again they worked overseas with just a plug adapter)
Some chargers are designed for one voltage only, and you would either need to replace them or tun through a transformer to step the British 240 volts down to 120. A few models (less common these days) have a little switch somewhere to let you select 120 or 240.
Many of the latest chargers are designed to operate over a very wide input range though. Have a look at the label on the unit, and if it says something like 90 to 250V, then you have such a unit. These will work fine with the appropriate plug adapter.
By the way, in the Middle East there are some areas using 220 to 240V supplies while others run on a 127-volt system. If your chargers were designed for 120V only you might have just been lucky and been in a 127V area.