The capacitor acts on the high frequencies of the pickups. He will filter these frequencies. The capacitors have different values ranging from 0.001 to 0.47mF.
The higher the value, the more it cuts the treble.
A .22mF capacitor cut less treble than a .47mF capacitor.
A simple pickup Fender is quite bright and rather acute. We will want to cut the most treble. So we will put a .47mF. But some guitarists like treble, for example on a Telecaster in country style, and will put a .22mfd. Like its’s a matter of taste!
A double humbucker pickup is rather dark. We will not want to remove too much treble. So we will put a .22mfd capacitor to use its whole sound palette.
Nevertheless, a Dark Metal player who plays rhythmically will be able to try a .47mfd capacitor, also a jazz player who wants a deafer sound too.
But in brief generally we have :
- .22mF for humbucking pickups
- .33mF for bass
- .47mF for single coil pickups.