How to Add a Guitar Pickup Emulator to Your LINE2AMP July 25, 2012 14:46 4 Comments
The PPE mod equips your LINE2AMP reamping kit with a classic, single-coil pickup output which, in addition to providing a new tonal option, allows it to interface more "authentically" with vintage guitar amps and effects.
While browsing Jack Orman's excellent "Lab Notebook" series, I came across his drawing of a simple guitar pickup emulation circuit. This article and the Passive Pickup modification for the LINE2AMP are greatly indebted to Orman's article. There are three electrical properties we must recreate to mimic a guitar pickup: inductance, impedance, and capacitance. Accordingly, our passive emulator circuit consists of only three components--you guessed it: an inductor, a resistor, and a capacitor. Together, these components form an low-pass filter with a resonant peak that is largely responsible for the unique tonal signature of a passive pickup.
The component values in the LINE2AMP (pictured above) recreate the performance of a standard single-coil pickup. The inductor and capacitor set the cutoff value for the low-pass filter at 5.5kHz, while the resistor damps the ringing of the resonant peak. This creates a filter with a smooth bump around the resonant frequency and a gradual LPF after.
Approximate Frequency Response
Performing the Passive Pickup Mod
- Mount both output jacks in the chassis. This will keep the work steady and allow us to better gauge the wire lengths needed.
- Trim the leads of the inductor and a length of black wire according to the distance between the jacks.
- Place the 820pF capacitor between the two pins of the Passive jack.
- Place one of the inductor leads in the Tip pin and one end of the black wire in the Sleeve pin of the Passive jack. Solder the inductor, capacitor, and wire in place. (Illustration 1)
- Solder the remaining leads of the inductor and wire to their respective pins on the switching side of the Active jack.