The Secrets of Electric Guitar Pickups
By Helmuth E. W. Lemme
Update: July 22, 2003
 Fig. 2. A pickup as an audio voltage source plus second-order lowpass 
The external load consists of resistance (the volume and tone potentiometer in the guitar, and any resistance to ground at the amplifier input) and capacitance (due to the capacitance between the hot lead and shield in the guitar cable). The cable capacitance is significant and must not be neglected. This arrangement of passive components forms a so-called second-order low-pass filter (Fig. 3).