on the original L-1000 basses, the switch was wired parallel/single-coil/single-coil with bass boost (aka, OMG mode)
they accomplished it by wiring a cap across one of the coils in series mode so it shunted one of the coils and boosted the output in the other, providing a few extra decibels of bass and treble but there were less mids. the later year L1Ks may have switch to a simpler setup with a basic series/parallel switch. on the old L1Ks with the 3-way switch, if you pop off the control plate and snip the cap off, you will have you series/single-coil/parallel settings. i did this to my '81 L1k and the difference is a tad less bass and treble but a good bump in the mids. thickens up the tone quite well.
they accomplished it by wiring a cap across one of the coils in series mode so it shunted one of the coils and boosted the output in the other, providing a few extra decibels of bass and treble but there were less mids. the later year L1Ks may have switch to a simpler setup with a basic series/parallel switch. on the old L1Ks with the 3-way switch, if you pop off the control plate and snip the cap off, you will have you series/single-coil/parallel settings. i did this to my '81 L1k and the difference is a tad less bass and treble but a good bump in the mids. thickens up the tone quite well.
