A lot of power transformers are built with dual primary windings. You put them in parallel for 120V and series for 240. Some even have taps for 100V Japanese power.
Look inside your equipment and see what's in there. For example some Adcom amps have a small board with terminals for 100/120/240 - you just replace the power cord and fuse.
Four wires connecting the power cord and transformer would be another clue.
Look inside your equipment and see what's in there. For example some Adcom amps have a small board with terminals for 100/120/240 - you just replace the power cord and fuse.
Four wires connecting the power cord and transformer would be another clue.