A magnetic recording disk drive comprising: a rotatable magnetic recording disk having a plurality of circular data tracks; a magnetoresistive read head structure for reading data from data tracks in a two-dimensional magnetic recording (TDMR) disk drive, wherein the trailing surface of the head carrier extends in a generally cross-track direction relative to the data tracks, the read head structure comprising: a head carrier having a surface for facing a disk and a trailing surface generally orthogonal to the disk-facing surface; a first magnetic shield on the trailing surface; first and second read heads (S3a and S3b) electrically connected to the first shield and spaced apart in a cross-track direction; a second magnetic shield on the trailing surface of the carrier; third and fourth read heads (S3c and S3d) electrically connected to the second shield and spaced apart in a cross-track direction different from the cross-track spacing of the first and second read heads, the third and fourth read heads being spaced from the first and second read heads in an along-the-track direction, the first and second shields being electrically isolated from one another; a first slider termination pad electrically connected to the first shield; and a second slider termination pad electrically connected to the second shield, the first and second slider termination pads being electrically isolated from one another; and a rotary actuator connected to the carrier for moving the carrier across the disk; a suspension comprising a first set of traces that includes a common trace connected to the first magnetic shield and traces connected to the first and second read heads, and a second set of traces that includes a common trace connected to the second magnetic shield and traces connected to the third and fourth read heads, the common traces being electrically isolated from one another; four amplifiers, amplifiers (A1-A4), each amplifier connected to a trace from an associated read head and its associated common trace; and switching circuitry connected to the amplifiers for selecting either first and third amplifiers of the four amplifiers or second and fourth amplifiers of the four amplifiers as an active pair, the unselected amplifiers being an inactive pair. a rotatable magnetic recording disk having a plurality of circular data tracks; a magnetoresistive read head structure for reading data from data tracks in a two-dimensional magnetic recording (TDMR) disk drive, wherein the trailing surface of the head carrier extends in a generally cross-track direction relative to the data tracks, the read head structure comprising: a head carrier having a surface for facing a disk and a trailing surface generally orthogonal to the disk-facing surface; a first magnetic shield on the trailing surface; first and second read heads (S3a and S3b) electrically connected to the first shield and spaced apart in a cross-track direction; a second magnetic shield on the trailing surface of the carrier; third and fourth read heads (S3c and S3d) electrically connected to the second shield and spaced apart in a cross-track direction different from the cross-track spacing of the first and second read heads, the third and fourth read heads being spaced from the first and second read heads in an along-the-track direction, the first and second shields being electrically isolated from one another; a first slider termination pad electrically connected to the first shield; and a second slider termination pad electrically connected to the second shield, the first and second slider termination pads being electrically isolated from one another; and a head carrier having a surface for facing a disk and a trailing surface generally orthogonal to the disk-facing surface; a first magnetic shield on the trailing surface; first and second read heads (S3a and S3b) electrically connected to the first shield and spaced apart in a cross-track direction; a second magnetic shield on the trailing surface of the carrier; third and fourth read heads (S3c and S3d) electrically connected to the second shield and spaced apart in a cross-track direction different from the cross-track spacing of the first and second read heads, the third and fourth read heads being spaced from the first and second read heads in an along-the-track direction, the first and second shields being electrically isolated from one another; a first slider termination pad electrically connected to the first shield; and a second slider termination pad electrically connected to the second shield, the first and second slider termination pads being electrically isolated from one another; and a rotary actuator connected to the carrier for moving the carrier across the disk; a suspension comprising a first set of traces that includes a common trace connected to the first magnetic shield and traces connected to the first and second read heads, and a second set of traces that includes a common trace connected to the second magnetic shield and traces connected to the third and fourth read heads, the common traces being electrically isolated from one another; four amplifiers, amplifiers (A1-A4), each amplifier connected to a trace from an associated read head and its associated common trace; and switching circuitry connected to the amplifiers for selecting either first and third amplifiers of the four amplifiers or second and fourth amplifiers of the four amplifiers as an active pair, the unselected amplifiers being an inactive pair.