Photo 1e.

Capacitor Cheat Sheet

Are you confused by capacitor nomenclature? Join the club!

To gain a thorough understanding of how caps work and how they’re labeled, Google “capacitor values.” In the meantime, here’s a handy cheat sheet showing the most common cap values for guitar applications.

The first number in each pair is the value in farads, the unit used to measure capacitance. The “µF” signifies microfarad—a millionth of a farad. People often substitute “uF” for “µF” to avoid the hassle of using a Greek letter. It’s also sometimes written as “MFD.”

The second number in each pair is the shorthand way of indicating these values, and that’s usually the number you find on the caps themselves.

The values appear in ascending order. The ones highlighted in green are typical values for conventional treble-cut tone controls. The ones in red are good starting values for the bass-cut controls in these projects. If a particular value doesn’t work for you, just step up or down in value till you hear what you like.

  • .0001 µF (101)
  • .00015 µF (151)
  • .00022 µF (221)
  • .00033 µF (331)
  • .00047 µF (471)
  • .00068 µF (681)
  • .001 µF (102)
  • .0015 µF (152)
  • .0022 µF (222)
  • .0033 µF (332)
  • .0047 µF (472)
  • .0068 µF (682)
  • .01 µF (103)
  • .015 µF (153)
  • .022 µF (223)
  • .033 µF (333)
  • .047 µF (473)
  • .068 µF (683)
  • .1 µF (104)

Regarding capacitor material: What sounds best? Ceramic caps? Mylar? Metal film? Mica? Tantalum? It doesn’t matter. In these applications, there’s no audible difference between various cap materials. Use vintage-style caps if you care whether your control cavity looks vintage.

This is a controversial statement, so feel free to disagree. But don’t expect to be taken seriously unless you can submit repeatable audio evidence demonstrating perceptible sonic differences between two caps of differing materials but equal value in standard guitar tone circuits. Anyone who does will receive my humble apology.

Capacitor hacks. If you find yourself lacking the perfect cap value, remember that you can wire together two caps in parallel, as shown in Photo 1e.

For once, the math is simple: The capacitance of parallel caps is equal to the sum of their values. For example, if you don’t have a .0015 µF, you can make one by soldering together two common caps, a .001 µF (102) and a .00047 µF (471) for a total capacitance of .00147 µF—well within the tolerance range of a .0015 µF cap.