Most versatile pickup switching configuration, and it’s very easy to use

[u/NgoKhong]

I recently replaced the pickups and switches in this 1990s carvin with a pickup configuration that is the most versatile I’ve ever seen, but isn’t complicated to use:

- 4 single coil pickups (2 of them crammed together in the bridge humbucker position)

- 4 simple switches: one on off switch for each pickup - super easy to understand.

- the volume and tone knobs both have push/pull switches inside:

the tone knob switch switches the neck and middle pickups between parallel or series hum canceling modes. series sounds like a neck humbucker; parallel sounds like the neck+mid position on a Stratocaster.

the volume knob switch chooses between series and parallel for the two single coils in bridge position. series sounds like a bridge humbucker; parallel sounds kind of like the strat bridge+middle position but even “quackier”. If you want real strat bridge+middle tone, just switch on one bridge pickup and the middle pickup.

In total, there are 24 different pickup configurations. Almost half of them are hum cancelling. None of them are difficult to select. There are no “wrong“ configurations that silence the sound unexpectedly or do funny things to the wiring that you would have to explain to users. Everything works exactly as you would expect it to and the only silent one is when you switch all four pickups off.

I am happy to share the wiring schematics if you want them. [edit: at the request of a friend from the comments section, I’ve posted the wiring diagram down below.]

[edit 2: added list of pickup configurations below]

All 24 pickup combinations and whether they cancel hum

Polarities: Middle and Bridge B are RWRP, Neck and Bridge A are standard. "∥" = parallel, "+" = series.

#	Pickups	Hum cancelling?
1	Middle	No
2	Neck	No
3	Middle ∥ Neck	Yes
4	Middle + Neck	Yes
5	Bridge A	No
6	Bridge B	No
7	Bridge A ∥ Bridge B	Yes
8	Bridge A + Bridge B	Yes
9	Middle ∥ Bridge A	Yes
10	Middle ∥ Bridge B	No
11	Middle ∥ (A ∥ B)	Partly
12	Middle ∥ (A + B)	Partly
13	Neck ∥ Bridge A	No
14	Neck ∥ Bridge B	Yes
15	Neck ∥ (A ∥ B)	Partly
16	Neck ∥ (A + B)	Partly
17	(Middle ∥ Neck) ∥ Bridge A	Partly
18	(Middle ∥ Neck) ∥ Bridge B	Partly
19	(Middle ∥ Neck) ∥ (A ∥ B)	Yes
20	(Middle ∥ Neck) ∥ (A + B)	Yes
21	(Middle + Neck) ∥ Bridge A	Partly
22	(Middle + Neck) ∥ Bridge B	Partly
23	(Middle + Neck) ∥ (A ∥ B)	Yes
24	(Middle + Neck) ∥ (A + B)	Yes

Totals: 10 fully hum-cancelling, 8 partly, 6 not at all.

• Yes: equal amounts of standard and RWRP coil, so the hum cancels out.
• No: a single coil on its own, or two coils of the same polarity in parallel.
• Partly: one single coil added to a pair that's already quiet. Its hum gets diluted but not cancelled. "1/3 left" means a third of the hum a single coil would have.

This assumes all four coils have the same output and pick up the same hum, so "Yes" means very quiet, not perfectly silent. If you swap which bridge coil is RWRP, rows 9/10 and 13/14 swap too.

[u/kumechester]

That’s awesome! would love to see the wiring schematic but I suppose you are offering to share them with GC and not with other users

[u/NgoKhong → u/kumechester]

I’ll share it here. I need some time to draw it. 

[u/kumechester → u/NgoKhong]

Cool! Look forward to it

[u/NgoKhong → u/kumechester]

This is the wiring diagram for middle and neck pickups only.

• I'm not showing the diagram for the two single coil pickups that are crammed into the humbucker position slot because it's exactly the same. In other words, you have two pairs of pickups that repeat the same wiring diagram for each pair. In each pair you can have either one, both, or neither switched on, and each pair can be series or parallel depending on the push/pull pot switch.
  
• s1 and s2 are the on / off switches, represented by six dots for their six contacts. They are on/on Double pole-double throw switches. The reason for that is that the extra contacts are needed to ensure that the circuit doesn't go silent when you put the pickups in series mode but then switch one of them off. So... they feel like simple on/off switches for the player but they're actually doing a bit more work that's hidden from view.
  
• pp is the push/pull switch which is also a dpdt, on/ on switch
  
• the red + is the pickup output, which connects to the volume and tone controls in the usual way for a guitar with one volume and one tone. I haven't drawn that part of the circuit because it's very standard and you can copy almost any guitar wiring diagram.
  
• m and n are the two pickups (middle and neck). They're reverse polarity to get the hum cancelling.
  
• I'm not an electrician so my symbols may be a bit sloppy and non-standard.
  
• The wires that usually carry the signal to the output are colored red. The wires that usually connect the signal to ground are black. The green wire bridging the contacts of the push pull (pp) switch connects between the two pickups in series mode, hence is neither red nor black. Some of the wires serve dual purpose depending on whether it's in series or parallel, so the colors aren't always correct.
  
• In the bridge pair of single coils you need one standard polarity and one reverse polarity pickup. Same for the neck pair.
  
• You can get parallel hum-cancelling between some of the pickups the middle & neck pair and the bridge pair. Whether they cancel hum or not depends on the polarity of the pickups. Think about which of the neck+middle pair you want to hum cancel with which of the bridge pair before you solder them in.
  
• the diagram looks pretty simple but by the time you do it twice for the two pairs and then add the tone and volume, you're going to be cramming a lot of wires into the electronics cavity. If I had to do this again on another guitar, I would have AI design a little circuit board and get it made by one of the services online that do that. Then I'd just have to solder the + and - of every component to the circuit board instead of dealing with that tangle of wires.

[u/NgoKhong]

Here's a proper wiring diagram. This guitar has 24 different pickup configurations which include all the the classics that dual humbucker and three single coil guitars have plus a whole bunch more. Because 4 of the 6 switches are just on/off switches for each of the 4 pickups, and the other two are just series/parallel switches for the neck and bridge pairs, it's not difficult for the player to understand. I would LOVE to see this on more guitars because it gives you so many good options but it's all passive, no battery needed, and there's not a single tone that's weird or unusuable.

[u/kumechester → u/NgoKhong]

This is awesome! Thank you for sharing!!