Wiring diagram feedback - coil split & series mode on a P90 + Humbucker circuit

[Linus Pickle]

I'm figuring out my wiring for a build I'm planning out using a P90 at the neck and a rail humbucker at the bridge. My goal with this is to get a few other options in addition to the usual 3 way switch setup - I've drawn this with a 4 position lever switch with the 3rd position being the neck and bridge pickups in series. I'm also hoping I can make a coil split on the bridge pickup work too, but I haven't been able to find any wiring diagrams that have both of those features.

Is this a workable idea? Am I at least heading in the right direction? I've done series/parallel wiring mods before but I haven't had any experience working with a coil split.

I do realize that I might need to adjust something if the P90 isn't in phase with the split coil on the humbucker.

(Also I goofed on my labeling for the switch positions and listed the bridge twice, I believe the 4th one should say neck)

Feedback, suggestions etc all welcomed, I am pretty green when it comes to designing wiring diagrams so I'm sure I've made a few errors at least.

 

[Deaf Eddie]

Close - you missed the lead from the 4-way to the volume pot (orange line):

Should work as expected.

The only potential issue is that your neck pickup should have independent negative and ground leads, which you don't show.

If it does not, you may get a little noise in the SERIES throw due to the fact that all the metal parts on the neck pickup are in the "middle" of the circuit, rather than being grounded. This is why when you use a standard two-lead Tele neck pickup in this circuit, you have to modify the pickup to give it a third lead to unground/reground the cover. IF you don't already have your P90 in hand, ask the maker to build it with three-lead wiring, with an independent ground/shield lead.

This potential issue could be avoided if you ran the series the other way - leave the P90 grounded and run the dual-coil pickup in series with it. You show the humbucker as a four-lead with separate ground/shield conductor- which is just what is just what you need to do this "electronically" correctly. You would also have to change the jumper on the coil-shunt switch (no biggie).

I may be being a bit too picky about this, but that's me.

For now, I suggest that you go ahead and wire it up as you drew it. Then, if the SERIES combo is a bit noisy, let me know and I'll draw it up the other way (as I described) for you.

 

[Linus Pickle]

Close - you missed the lead from the 4-way to the volume pot (orange line):

View attachment 1225498

Should work as expected.

The only potential issue is that your neck pickup should have independent negative and ground leads, which you don't show.

If it does not, you may get a little noise in the SERIES throw due to the fact that all the metal parts on the neck pickup are in the "middle" of the circuit, rather than being grounded. This is why when you use a standard two-lead Tele neck pickup in this circuit, you have to modify the pickup to give it a third lead to unground/reground the cover. IF you don't already have your P90 in hand, ask the maker to build it with three-lead wiring, with an independent ground/shield lead.

This potential issue could be avoided if you ran the series the other way - leave the P90 grounded and run the dual-coil pickup in series with it. You show the humbucker as a four-lead with separate ground/shield conductor- which is just what is just what you need to do this "electronically" correctly. You would also have to change the jumper on the coil-shunt switch (no biggie).

I may be being a bit too picky about this, but that's me.

For now, I suggest that you go ahead and wire it up as you drew it. Then, if the SERIES combo is a bit noisy, let me know and I'll draw it up the other way (as I described) for you.

Thank you very much Eddie! The P90 does not come with a separate shielding ground but I can ask Ryan at Bootstrap if they will do that - I know they're good about responding to that sort of thing so I'm optimistic that they'll be able to do something. I will email them and see. I assume the extra ground wire from the neck pickup just goes on the back of the volume pot with the other ground connections?

 

[Deaf Eddie]

"I assume the extra ground wire from the neck pickup just goes on the back of the volume pot with the other ground connections?"

Yup.

 

[Tuxedo Poly]

This is one possibility if you can't get the P90 with separate grounds. I've not tried it but it looks feasable. It is the Fender pickup switching sequence not as above. The red and green of the rail also may need swapping.

 

[Linus Pickle]

This is one possibility if you can't get the P90 with separate grounds. I've not tried it but it looks feasable. The red and green of the rail also may need swapping.View attachment 1226008

Cool, thanks. I emailed Bootstrap but haven't heard back yet, so a backup plan is helpful.

I'd swap the red and green wires if the coil split sends the wrong coil (the one that's not RWRP with the P90) to the ground, right?

 

[Linus Pickle]

I've been trying to wrap my head around the extra ground wire for a telecaster neck pickup in series. I found this article on Lindy Fralin's site about how to convert a 2 lead pickup to a 3 lead with an extra ground, but it only applies to pickups with a metal cover, which my P90 will not have.

Is a second ground wire necessary or even possible in this case? Where would I attach it to on the pickup if there's no metal cover?

 

[Bob J]

I put a squeaky clean in the neck with a Palo Duro in the bridge with a 4-way switch. I just ignored the neck cover ground wire in n the schematic

 

[peterg]

I've been trying to wrap my head around the extra ground wire for a telecaster neck pickup in series. I found this article on Lindy Fralin's site about how to convert a 2 lead pickup to a 3 lead with an extra ground, but it only applies to pickups with a metal cover, which my P90 will not have.

Is a second ground wire necessary or even possible in this case? Where would I attach it to on the pickup if there's no metal cover?

P90s have a metal baseplate which is grounded. If the P90 only has 2 wires then one is attached to the baseplate plus one end of the coil. Reversing the wires on a P90 requires taking apart the pickup.

 

[jfgesquire]

I've been trying to wrap my head around the extra ground wire for a telecaster neck pickup in series. I found this article on Lindy Fralin's site about how to convert a 2 lead pickup to a 3 lead with an extra ground, but it only applies to pickups with a metal cover, which my P90 will not have.

Is a second ground wire necessary or even possible in this case? Where would I attach it to on the pickup if there's no metal cover?

Your P90 does not have a metal cover, but it does have a metal base plate, AND if you reverse your wires at the switch/pots to be in phase, the end wire on the pickup will actually end up on the hot side. Your pole screws touch that metal baseplate so you need to separate the ground wire. It is really no different than a Tele bridge pickup ground wire with a small section of the wire soldered to the baseplate.

I did this mod for a 4-way switch...

 

[Freeman Keller]

P90s have a metal baseplate which is grounded. If the P90 only has 2 wires then one is attached to the baseplate plus one end of the coil. Reversing the wires on a P90 requires taking apart the pickup.

Another way to say that is to put two pickups in series one of them has to have both ends of the coil available and ungrounded. To abate noise its desirable to have the metal parts of the pickup (enclosure, baseplate) grounded.

There are lots of descriptions on how to modify a pickup to do this, here is a neck P90

 

[Deaf Eddie]

EDIT: after closer study of Tuxedo poly's post, these edits may NOT be relevant...
His drawing looks good!

********************************
Here are a couple of edits I did. Note that I have the series pair on the MIDDLE lug of the p/p, and the blue lines are the shunt leads. When you shunt to the hot, you get the red and black coil; when you shunt to the negative, you get the green and white coil.

Coil-shunt plays RED and BLACK coil:

Coil-shunt plays GREEN and WHITE coil:

Note that if the color code in the drawing does NOT match your pickup, you will have to translate the colors in the drawing to match your pickup. I can help with that if needed.

 

[Linus Pickle]

Tuxedo poly has posted a neat drawing, but there are several errors. The series jumper is in the wrong place and the coil-shunt p/p wiring is goofy.

Here are a couple of edits I did. Note that I have the series pair on the MIDDLE lug of the p/p, and the blue lines are the shunt leads. When you shunt to the hot, you get the red and black coil; when you shunt to the negative, you get the green and white coil.


Coil-shunt plays RED and BLACK coil:
(link removed)


Coil-shunt plays GREEN and WHITE coil:
(link removed)

Note that if the color code in the drawing does NOT match your pickup, you will have to translate the colors in the drawing to match your pickup. I can help with that if needed.

Thanks again Eddie- DiMarzio says their green wire is the ground and red is hot, while the black and white wires are the two leads to connect if wiring the pickup in series. So I think you've got it correct, except that the green and red need to be swapped (the key on the diagram is incorrect)

 

[Deaf Eddie]

Right, swap red for green - unless your P90 plays out of phase (unlikely) then you would wire it as it is drawn.

 

[jfgesquire]

Another way to say that is to put two pickups in series one of them has to have both ends of the coil available and ungrounded. To abate noise its desirable to have the metal parts of the pickup (enclosure, baseplate) grounded.

There are lots of descriptions on how to modify a pickup to do this, here is a neck P90

View attachment 1226018

I was getting wordy and didn't know how to explain it. Thanks for finishing my thoughts precisely and concisely!

 

[Linus Pickle]

Right, swap red for green - unless your P90 plays out of phase (unlikely) then you would wire it as it is drawn.

Or... perhaps not. The DiMarzio arrived this afternoon and I opened the box to see this little bit of information:

Interesting choice on DiMarzio's part - I wonder why they do it that way?

 

[Deaf Eddie]

Good info!

 

[Tuxedo Poly]

That is the way the rail is wired. They use it on the Richie Kotzen wiring diagram
Got to disagree with Deaf Eddie about the pushpull coil shunt.
It's not goofy but a method Fender have used for coil splitting.
This might help explain how it functions for a split to the south coil.

Can't find fault with my diagram either.

4 way switch numbering

This is how it appears to work

Pos 1 Bridge - ground on 4 way A2 linked to A1 switched to 4 way A0 (common) to HB red through HB coils out on HB green (hot) switched by pp to white from push pull common to A3 linked to B2 and B3 wired to volume. Neck hot wired to B0 common switched to unused B1

Pos 2 B+N Parallel - neck hot on B0 common switched to B2 linked to B3 wired to volume, bridge ground on A2 switched to A common as Pos 1 above

Pos 3 Neck - neck hot on B0 common switched to B3 wired to volume. bridge HB short cct between A0 common and A3

Pos 4 B+N Series - neck ground on volume pot, neck coil, neck hot wired to B0 common switched to B4 linked to A4 switched to A0 common bridge red, coils, out on bridge green (hot) to pp switched to pp common (white) wired to A3 linked to B2 and B3 wired to volume

 

[jfgesquire]

Or... perhaps not. The DiMarzio arrived this afternoon and I opened the box to see this little bit of information:View attachment 1226119

Interesting choice on DiMarzio's part - I wonder why they do it that way?

Interesting. The plate doesn't effect the impedance, but it does affect the inductance. You can even put a small plate on the bottom of a Strat pickup to give it a little more punch. Maybe they felt their P90 was punchy enough without it.

 

[Linus Pickle]

Interesting. The plate doesn't effect the impedance, but it does affect the inductance. You can even put a small plate on the bottom of a Strat pickup to give it a little more punch. Maybe they felt their P90 was punchy enough without it.

Maybe, however I'm not using a DiMarzio P90 - this is from a Tone Zone T rail humbucker. The P90 has been ordered from Bootstrap and I probably won't see it for another few weeks.