P-Rails... diving in

alex1fly

alex1fly

Well-known member
Hi all! Starting a thread to track progress on installing a set of P-Rails. Been reading about it and it seems like this is a good starter scheme... I don't really use split coil sounds much, so parallel/series/P90 sounds like a solid place to begin.

image.png
https://www.seymourduncan.com/blog/latest-updates/the-p-rails-wiring-bible-part-2

Already I'm wondering... can this switch be an existing push/pull pot, or do I need to order up something like this: https://reverb.com/item/34461910-on...gle-switch-round-bat-lever-guitar-bass-chrome
There's "ON ON ON" and "ON OFF ON" switches which is a little confusing...
Also I'm wondering if I do separate DPDT switches for each pickup (assuming yes

I'm sure I'll have a lot more questions once I open the guitar up and see what the stock wiring is. Generally I prefer to maintain as much stock wiring as possible... the less I muck around inside there, the better lol

Anyways thanks for coming on this ride with me. Sure would be simpler to just put like a Custom/PG set in there but I already have the P-Rails and am quite curious about them!
 
alex1fly said:
Already I'm wondering... can this switch be an existing push/pull pot
Click to expand...

Hello,
The wiring shown in the pic that you've shared requires a 3 positions switch. A push/pull has only two positions and would allow series + only one split option.
That said, an ON OFF ON switch can be wired to offer split / series / split and one could even use one single ON OFF ON switch for TWO pickups. Actually, I've that on a guitar...
The trick to do that is to wire the black wire and hot output altogether to one of the external lugs in a row of three (bottom or upper lug if the switch is positioned like in your pic, with two rows of poles horizontally and 3 rows of poles vertically). On the other external lug, solder altogether the green wire / bare wire. On the center lug, solder altogether the red and white wire. It will give series wiring in center position and one coil only in each of the two extreme positions.
Do the same on the other vertical row of three poles for the other pickup - or reverse the wiring in order to have coil A enabled in the same time than pole B in the other pickup, or conversely...

Yes, I know, wordy post. If needed, I'll try to share later a pic showing how to wire this ON OFF ON switch. :-)
 
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freefrog said:
Below how to wire an ON OFF ON switch to have split / series / split modes...



Click to expand...

Thanks! I wired it up as just P90s for now as per the Duncan link… just hot and ground, with the other wires disconnected. Sounds good, nice and clear, like a refined Telecaster. Definitely want more beef on tap though so I’m looking forward to trying parallel and series with the on/off/on switch.
 
At least, I assume it’s the P90 with just hit and ground. Both the screws and the rail pop when I touch them with a screwdriver, guess I figured the rail would be silent in P90 mode. It’s definitely not a HB sound and does hum in the neck and bridge positions. Regardless, definitely an improvement over the 58/15s in the guitar (prs s2 standard). Got a love/hate relationship with that series of pickups.
 
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alex1fly said:
Thanks! I wired it up as just P90s for now as per the Duncan link… just hot and ground, with the other wires disconnected. Sounds good, nice and clear, like a refined Telecaster. Definitely want more beef on tap though so I’m looking forward to trying parallel and series with the on/off/on switch.
Click to expand...

You're too generous to thank me, since I've initially done a mistake in my interpretation of the Duncan schematic AND have realized that an equivalent of my own schematic shared above was already on the Duncan page, just above the pic that you've mentioned... :-P

That said, now that I've scrolled a bit more attentively through this Duncan page: there's an ambiguity, apparently due to a redactional error. The text says: "you can use an on/off/on DPDT switch to achieve series/P-90/parallel modes like this". But the image just under it (the pic that you've shared abovein this topic) achieves Series/split/parallel with an ON/ON/ON switch...

So and just to be clear: either you can use an ON OFF ON switch for split / series / split, either an ON ON ON switch giving series, P90 alone or both coils in parallel. In any case, the beefier option should be the series mode. Parallel should be noiseless but slightly weaker than either split option...

FWIW. Hope I've not done any mistake this time. :-)

alex1fly said:
At least, I assume it’s the P90 with just hot and ground. Both the screws and the rail pop when I touch them with a screwdriver, guess I figured the rail would be silent in P90 mode. It’s definitely not a HB sound and does hum in the neck and bridge positions.
Click to expand...

BTW...
- if hot and ground are connected and white + red taped altogether, you have the whole series mode and not the P90 alone (which would require white as ground and black as hot).
-the P-Rail being not symetrical, I wouldn't expect it to cancel the hum quite like a Gibson style HB. Nor would I expect it to sound like a "normal" humbucker in series (the inductance of the P-Rail bridge in series mode seeming to be in the range of Hot Rails, IOW very high).
Now, parallel mode might be interesting, since it should give the inductance of a typical Fender single coil in bridge position and the inductance of a Filter'Tron with the neck PU (with tones in the ballpark of these references, therefore)...
​
 
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When I wired up my on off on switch for the half rails i put min my blue ehdwuld headless

The rail and screw coil made a sound on on pickup but not the other

The bridge behaved nicely
The neck was suspicious

But it all works just fine
 
Man now I’m wondering what options there are with the existing push/pull. It was previously wired for coil split.

Unfortunately there’s not much room under the pick guard to add switches, and being a pick guard guitar there’s no room for Triple Shots. I’d love to be able to click between series and P90 or series and parallel.
 
alex1fly said:
Man now I’m wondering what options there are with the existing push/pull. It was previously wired for coil split.
Click to expand...

For one pickup, down, can give you series, parallel, or split to one coil or the other, but not both. Up will do the same thing, so you have to decide which two modes you want most.

For two pickups, down will give you series, or split to one coil or the other, for both pickups. (But one could be series, while the other is split.) Same for up. So, again, you decide which two you want. A popular option for two pickups, would be both series when down, P-90's when up.
 
alex1fly said:
Man now I’m wondering what options there are with the existing push/pull. It was previously wired for coil split.

Unfortunately there’s not much room under the pick guard to add switches, and being a pick guard guitar there’s no room for Triple Shots. I’d love to be able to click between series and P90 or series and parallel.
Click to expand...

Spontaneously, I agree with what Artie said.

Now, scrolling in the Duncan pages made me realize they had an interesting schematic with two push-pull pots in the "Part 3" of their discourse about P-rails:

https://www.seymourduncan.com/images/wiring-diagrams/2PRail_3G_1VppSPL_1TppSPL.jpg

TBH, I haven't tried to check this schematic by myself but if it works, I find it very clever and salute the Duncan staff for that... :-)
 
I might pop the guard off and solder the green and red wires (the rail pickup) the coil split to see what happens. Or solder them together. Right now they’re just dangling in the cavity with electric tape over the ends.

assuming/hoping this isn’t a bad idea. Just want to try some of the different sounds before committing.
 
alex1fly said:
I might pop the guard off and solder the green and red wires (the rail pickup) the coil split to see what happens. Or solder them together. Right now they’re just dangling in the cavity with electric tape over the ends.

assuming/hoping this isn’t a bad idea. Just want to try some of the different sounds before committing.
Click to expand...

Not sure to understand but if you solder green and red to the coil split (IOW: to the white wire), the pickup won't be grounded no more... Unless you've already put white to ground and simply left green/red unused?

I sympathize with the idea to try different options anyway. When I have to do that on a guitar with a pickguard, I leave sometimes the wires of a pickup sticking out from the cavity and I connect them in different ways. In this case, I'd try...
-Green to ground, black to hot, white and red taped altogether (series).
-Same thing with a jumper between grounded green and white/red (P90 mode).
-Same thing with the jumper between white/red and black to hot (rail mode).
Only the parallel mode will/would be more tedious to try as it requires green + white to ground and red + black to hot...

Do what you want and be happy. :-)
 
nice I have a p-rails project coming up for a customer but I think he wants to use the triple shot rings
 
I've had the P Rails in my HH partscaster jazzmaster for the last 15 years with the two push-pull setup. Honestly I find myself using the p90 and parallel 90% of the time. Flipped the neck earlier this year and use the rail coil more now but it's still somewhat dark compared with a true strat pickup. Not a bad sound at all just not "strat" IMO.

One other thought - don't know what guitar you're putting these in, but if it's a strat you've got 3 knobs to work with, so you can use one as a blend pot and get a 3-way super switch to go between series, parallel, and p90.
 
Came across this thread, I love the p-rails but in some guitars some sounds like in series sound muddy almost unusable in some of my guitars I installed fender tbx tone controls along with a tone bypass switch ( I use triple shots) but the tbx on "10" really cuts the mud in the series position and gives a powerful ballsy clear tone and the bypass switch just cuts the tone out completely which gives an even more interesting raw tone.especially in p90 mode.
 
the prails (normal one) in series sounds very thick to me, i use the parallel and p90 options most of the time
 
Series was too thick for me. The P90 and parallel sounds are where its at for me, but that wasn't enough for me to keep them in the guitar.
 
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