In one illustrative example disclosed, a magnetic storage device includes
at least one magnetic disk; a magnetic head which includes first and
second read sensors; a suspension which supports the magnetic head
relative to the magnetic disk; and read circuitry which includes a
preamplifier. The preamplifier has a first input port coupled to the
first read sensor; a second input port coupled to the second read sensor;
a first bias source coupled to the first input port for actively
current/voltage biasing the first read sensor; a second bias source
coupled to the second input port for zero biasing the second read sensor;
and a subtractor having first and second inputs coupled to the first and
the second input ports, respectively. The first input of the subtractor
is provided with a first signal which includes a read sensor data signal
and an interference signal, whereas the second input of the subtractor is
provided with a second signal which includes the interference signal but
not the read sensor data signal. Thus, an output of the subtractor
provides a read sensor signal without the interference signal.