A preamplifier with Junction Field Effect Transistor (JFET) makes your guitar sounds great, operating in similar manner to the vacuum tubes. This circuit is very simple to build and can be also used as a booster. Additionally, the high input impedance will enhance the bright tone of your guitar. With this PCB you can use trimmers to easily adjust the bias point and behavior of the transistor. You can use a voltmeter to measure the voltage of the source (Vs) and drain (Vd) on the PCB pads. Materials list 1x JFET Preamp DIY PCB 1x 47NF 0.047UF 100V 5% POLYESTER FILM BOX TYPE CAPACITOR   1x 220PF 50V CERAMIC DISC CAPACITOR 1x 100UF 35V 105C RADIAL ELECTROLYTIC CAPACITOR 6X11MM 1x J201 JFET N-CHANNEL AMPLIFIER TRANSISTOR 1x 1M OHM 1/4W 1% METAL FILM RESISTOR 1x 33K OHM 1/4W 1% METAL FILM RESISTOR 1x 5K OHM TRIMMER POTENTIOMETER CERMET 1 TURN 3362P 1x 50K OHM TRIMMER POTENTIOMETER CERMET 1 TURN 3362P 1x 100K OHM LOGARITHMIC TAPER POTENTIOMETER