A disk drive includes a disk, a voltage supply, a head stack assembly and a switching
circuit. The head stack may include a coil portion that includes a coil assembly
having first and second wound coils. The switching circuit is electrically coupled
to the voltage supply and to the coil assembly, and is configured to selectively
switch the first and second wound coils between a first configuration and a second
different configuration in which the first wound coil is electrically in parallel
with the second wound coil.