Two channels meet at the selector
The supported passive Les Paul-style circuit has a volume and a tone control for each pickup. Each pickup signal feeds the corresponding volume input; each volume wiper supplies one selector input. The selector chooses neck, bridge or both and sends the resulting connection to the output jack TIP.
Four knobs do not mean four isolated signal sources. The pickup channels share the output path and ground network. In the combined position they can load one another through that connection, so a control can influence the result differently than it does with only one pickup selected.
A volume pot is a divider and a load
Apparition identifies volume lug 3 as signal input, lug 2 as wiper/output and lug 1 as ground. The full track loads the pickup while the wiper selects an output point along it. Turning the knob changes attenuation and the impedance presented to the cable and amplifier input.
The nominal resistance and taper are different specifications. Resistance contributes to loading; taper changes resistance progression with rotation. A knob set to five is not a calibrated promise of half loudness, and replacing a control with a different taper can alter the useful sweep even when its nominal resistance stays the same.
Why one volume can affect both pickups
In the conventional supported wiring, the both position connects the two wiper outputs to a common output. With a volume fully down, its wiper approaches the grounded end of the track. That can pull the shared output toward ground and mute the combined signal. This behaviour does not by itself identify a faulty selector.
At intermediate positions the interaction is more nuanced than adding two independently fixed levels. Pickup impedances, control resistance and the connected loads matter. The current response tool does not validate the combined-pickup response, so its single-pickup curve should not be presented as a simulation of this blend.
Each tone control loads a signal node
A tone pot and capacitor form a frequency-dependent loading branch toward ground. In Modern wiring that branch originates at volume input lug 3; in the supported 50s configuration its feed comes from the volume wiper lug 2. The main path still reaches the jack without an inline tone capacitor.
The tone setting, capacitance and pickup impedance together influence the response. A larger capacitance does not establish a universally better sound, and a capacitor material name does not supply an electrical explanation. Choose values deliberately and inspect the specific wiring before attributing a change to a component.
Selected does not mean every other node disappears
A selector opens and closes contacts; it does not rewrite the whole harness. The disconnected channel still has its own controls and ground connections, while the selected contacts establish which output paths are joined. A switch label must be checked against the actual contact arrangement.
Do not assign contact functions by the direction of a photograph alone. The correct common, pickup inputs and ground/shield point depend on the part. Use the part documentation and continuity checks alongside the Generator’s supported reference.
A useful test sequence
Begin with a known-good cable and an identified jack TIP/sleeve pair. Select one pickup, check its volume through the travel and then its tone adjustment. Repeat for the other pickup before checking the combined position. This isolates a channel problem from a shared output fault.
If there is no output in every position, inspect the shared selector output and jack before replacing four controls. If only one pickup fails, follow that channel from pickup hot to volume input and wiper. Keep a note of the configuration and use continuity evidence rather than the visual neatness of a joint.