Capacitors work as hi-pass filters in electric guitar circuits. They block lower frequencies in the signal and allow higher ones to come through. The rating of the capacitor determines how much of the lower tone signal will be audible. A higher-rated capacitor allows more of the higher frequencies to pass through. Different capacitor materials affect tone as well, and some materials work better than others.
Farad ratings identify capacitors. Many electric guitars use capacitors rated .022 mfd (micro farads). Another common rating stands at .047 mfd. Players who turn their volume knob down, often insert a .001 mfd capacitor on their volume control to maintain high frequencies at lower volumes.
Many stock guitars commonly employ ceramic capacitors. Upgrades often include film capacitors, those made of materials such as polystyrene and Teflon. Professionals regard oil/paper capacitors as another option for improvement. The cost of oil/paper capacitors often exceed those of film capacitors.
Orange drop film capacitors made by Sprague produced legendary changes to tone. SB Electronics now manufactures these components, retaining the quality of the original products. The 715P and 225P provide exceptional results in Fender Stratocasters.
Sprague Vitamin Q capacitors were once popular for use in hi-fi audio equipment. Guitar players seek these vintage caps for use in guitars. Allparts, a guitar and amplifier parts distributor, now manufactures a reproduction of the original.