TinkercasterWhen you are ready to wire it
The WD_MM_3B replacement circuit, not a universal map for every Music Man, StingRay or Sterling bass.
Three positions, one pickup
The source labels position 1 parallel, position 2 split and position 3 series. Parallel uses both coils side by side; series joins them in a chain. The middle is the source’s split arrangement.
A 3.3 kΩ resistor bridges two switch terminals. Preserve it when reproducing this circuit. Do not replace it with a generic hard-split circuit or infer exact noise and output performance from the word “split”.
Follow the blade switch
In the source orientation, the upper row receives white at its first terminal and green plus bare at its second, with that second terminal grounded. A 3.3 kΩ resistor bridges upper third and fourth.
The lower row has black at its first terminal and red at its fourth. A jumper joins lower third to upper fourth. Output joins black and goes to the preamp’s gray wire, as labelled by this source. Switch layouts and preamp colours are not universal.
Two-coil and three-coil versions differ
The sheet warns that a stock pickup with a third coil underneath needs the corresponding three-coil replacement. A standard two-coil pickup is not a drop-in substitute.
Its examples mention Sterling and certain five-string StingRay instruments. Identify the actual electronics revision rather than deciding from name or age alone.
Before replacing anything
Confirm the original coil arrangement, blade contact map and preamp lead identification. This guide explains the sheet; it is not a verified native simulation of the preamp.
Source and interpretation
Original explanation by Tinkercaster, based on these Seymour Duncan sheets: WD_MM_3B. The guide describes the stated configuration; it does not establish compatibility with every pickup or switch.
Seymour Duncan’s wiring diagram library ↗
Not affiliated with or endorsed by Seymour Duncan. Refer to your exact component’s instructions when a detail differs.