Those capacitors and resistors form a treble bypass circuit.
Normally, on a Jazz bass, your pickups' tone is affected by the volume control as well as the tone control. If you turned only the bridge pickup up and then slowly brought it down, not only would the bass be quieter, but it'd also lose a lot of its high end and become duller.
The resistor and capacitor across the input-output lugs make sure the highs do not get affected by the current volume turn - instead, the sound remains crisp even if it's quieter.
Originally Posted by rtav
Progressive Rock is like pornography - it can be hard to define but I know it when I hear it.
Originally Posted by Nev375
Fission is like fusion, but the original genre is obliterated in the jazz process.
Brony bassist #42