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Schaller 'p' Megaswitch


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Firstly i'll freely admit that guitar electrics are not my forte in any shape or form.

I have a customer that wants a Schaller 'P' switch used in his build - 2 humbuckers. Now, everywhere it says that seeing the contacts are numbered it couldn't be simpler to wire up - sounds like my kind of wiring. As the switch came from Germany in OEM type packaging (a Schaller polybag without instructions) i went onto Stew Mac's wiring section and was confronted with the following text:

For the 'P' Model Megaswitch to work properly, the pickups must be correctly installed. The outside coils of the pickups must have opposite magnetic polarity. To check this, place one pickup over the other. If the pickups repel each other, the coils have the same polarity. The pickups will attract each other if their polarities are opposite.

The pickups i have, WB Firewater matched set, the coils have the same polarity - they repel each other when placed on top of each other - so does this mean i just have to mount the neck pickup back to front or do i have to change the wiring or am i stuffed ?

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I'm confused at whether "over the other" means face-to-face or stacked both facing up :D

I bought one for my new build. Haven't got around to wiring it though. Thankfully you can't tell if the pickup is upside-down or not. I would install them backwards and then check to see if they work properly. It's a good thing the issue rests on moving a pickup backwards, as opposed to a wiring issue. Easier to fix.

I'm in the same boat as you, though. Electronics aren't my thing. I'm glad someone else is running into this issue before I do, though!

My plan is to see which of the 3 other options I like, and at some point down the road switch out the P-Switch with a Superswitch, keep the selections I like, and throw in phasing or coil tap on the ones I don't. Oh, glorious over-the-top wiring schemes...

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For the 'P' Model Megaswitch to work properly... the outside coils of the pickups must have opposite magnetic polarity.

The pickups i have....the coils have the same polarity - ....so does this mean i just have to mount the neck pickup back to front or do i have to change the wiring or am i stuffed ?

i've done lots of two humbucker installs like this. you have several choices:

--mount the neck pickup back-to-front. if it has a logo on it or one coil of screw poles, it will look weird this way. you will also have to change the wiring, reversing the hot & ground wires, and maybe also swapping the series link wires for the hot & ground (if the middle switch positions sound out of phase).

--install the pickup normal, and just accept the fact that the switch positions aren't going to give the best coil-cut combinations. so instead of outer coils or inner coils, it would be bridge outer + neck inner and bridge inner + neck outer. they will all hum-cancel, but neither of those sounds as distinct as both inner or both outer.

--my favorite solution: pop the magnet out of the neck pickup, rotate it flat 180 degrees, then put it back in. this changes the magnetic polarity so you can install the pickup normal but still have the proper middle switchs positions and still have them hum-cancel. you may have to change the wiring to get the phase right, but at least you know the magnet polarities are right and there is a wiring combination for the neck pickup that will make everything hum-cancel.

Edited by scott from _actual time_
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  • 3 months later...

Boink! Bumping an old thread again! I'm finishing the finishing on my guitar this week, so I wanted to get any electronics questions out of the way first. I know I responded up earlier in the thread, but I wanted to re-ask:

My pickups (PAF Pros) are neither bridge nor neck-specific, and have two sets of screws. Thusly, how can I tell if I'm installing them "upside-down"? They do have stickers on the baseplates with the model numbers on them. Should I assume that the stickers are meant to be read with the headstock being "up"? The Dimarzio website says it doesn't really matter if they're upside-down or not, but I'd still like to install them right.

I'll probably end up just flipping the pickup, because you can't tell that they're upside-down anyways. Scott, if you see this, would only the hot and ground wires need to be switched?


I just picked up a potentially huge detail on this scheme. The Dimz website links to this diagram for installing their version of the P Megaswitch. Aside from the wiring differences between it and the StewMac version, the diagram also shows both pickups facing in the same direction, with the text on them being read with the bridge being "up." Very interesting.....

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I just finished modding my strat so that the middle coil is moved down next to the bridge, like a slant humbucker. At first, I was worried about the pickup direction because I would have had to saw off one of the tabs on the bottom bobbin to get the two coils to lay next to each other. I posted a question about it on another forum, and a helpful luthier told me that it didn't make a difference which way the pickup was oriented. Sure enough, he was right. But, that's for single coils. I have a feeling it's the same for humbuckers too. I would just wire it up and if it sounds out of phase, you'll know it and it'll be an easy fix.

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