Patent ID: 7206155

Claim:
A hard disk storage system, comprising: (a) a magnetic disk; (b) a head for writing data to said disk; and (c) a preamplifier for orienting a current through said head in a desired direction responsive to a data signal, said preamplifier comprising: (i) first and second output ports for coupling to said head; (ii) first, second, third, and fourth output devices for driving a current through said head, said first and third output devices connected to said first output port, and said second and fourth output devices connected to said second output port; (iii) a first matching resistor coupled between a first reference node and said first output port; (iv) a second matching resistor coupled between a second reference node and said second output port; and (v) control circuitry for maintaining the voltage of said first reference node at substantially the same voltage as said first output port and for maintaining the voltage of said second reference node at substantially the same voltage as said second output port. (d) whereby current through said first and second matching resistors can be minimized.