Question about rotating neck pickup 180 degrees

[Greg Jones]

Yesterday during a string change on my SCT I decided to flip the neck pickup (a Duncan PG) around 180 degrees ala Peter Green. It has a Duncan CC in the bridge.

Funny thing was, after I got her restrung and plugged her in the middle position DID NOT yield the quack and loss of output being out phase usually does. ???

How is this possible? Mr. Collins. ??? I sure would like to understand this. The neck pup now sounds a bit brighter, a little less muddy, which was what I wanted. I was certain I'd be out of phase though with the bridge pup and have the weird sounding middle position. I expected that and was prepared to live with it. How can it be that both orientations of the neck pickup do NOT produce this???

Thanks in advance for any input.

[Serious_Poo]

I've done this on a lot of my guitars, and I find that sometimes it's more noticable as you go higher up the fretboard. Also, I suspect lower output pickups may react differently than higher output pickups.

[Greg Jones]

Thanks Poo.

When my SCT had the stock #6 in the neck and I first installed the CC in the bridge the SD and PRS pups were out of phase and it was as obvious as getting hit in the head with a hammer. I had the CC wired up 'normally', so I just reversed the hot and ground wires 'til I got the PG. Then changed the CC's wiring back to normal, wired in the PG normally.

Guess I shouldn't be complaining but it did strike me as odd. Especially since I heard the CC and #6 when out of phase.

[Jim Collins]

The orientation of the pickup has no effect on its phase relationship to the other pickup. I recall from physics class -- I think I took physics when Newton was still nursing a bruise from that apple -- something called the "right hand rule."

Make a fist with your right hand, but leave the thumb pointing out. Your thumb points to magnetic north, and your fingers point in the direction of current flow. You can move your right hand any way you want, but the fingers and thumb maintain their relationship. (This is, of course, obvious, or else there were would be fingers and thumbs lying all over the ground, from people moving their hands.) So it is with pickups and their phase relationship. Your right hand is a representation of a pickup. By simply rotating the pickup 180 degrees, you haven't changed the phase relationship, because the coil and magnet have not moved, relative to each other.

The right hand rule governs how pickups should be connected to maintain a proper phase relationship to each other. To create an out of phase condition between two pickups, one -- and only one -- of the following must be changed. You either reverse the magnetic polarity of ONE pickup (for a humbucker, this means flipping the magnet), OR you reverse the positive and negative leads of ONE pickup.

The Peter Green sound has two components, and these components are not related to each other. The first is the rotated neck pickup. All this does is put the adjustable pole pieces under a different part of the strings. If the adjustable pole pieces are raised a bit higher than the slugs in the other coil, the resulting sound will be a bit different, even when the pickup is used alone.

The second component is phase. You have two choices, here. You can either flip the magnet of the neck pickup, or you can reverse the positive and ground leads of the neck pickup. Actually, you can do this to either pickup, and it won't make any difference. If you choose to reverse the positive and ground leads, make sure your pickup does not have vintage style wiring, in which the coil ground is integrated into the base ground. The metal base of the pickup must always be grounded, regardless of the phasing.

[Greg Jones]

Thanks Jim!!!

Excellent explanation as always!!! This is one for the archives I'd think. Right hand rule eh? I've heard that before in the context of why gyroscopes work. Coriolis effect.

I'll leave it as is. Didn't really want the OOP sound.

So this experiment also tells me that the phase relationship between a normally wired Duncan vs. a normally wired PRS pickup is 180 degrees out due to the magnetic poles being opposite between the two.

[Jim Collins]

Two pickups can have opposing magnetic polarity, yet still be in phase. As long as each pickup is wired in accordance with current flow for that pickup, the pickups will be in phase. By the same token, two pickups can have the same magnetic polarity, yet be out of phase, if one of them is wired "backwards." You wouldn't be able to tell if pickup was wired "backwards" if that pickup were the only one in the circuit.

[Greg Jones]

Ooh!!!

It just dawned on me while trying to visualize the difference between SD and PRS pickups.

If I hold my right hand in a fist with my thumb pointing up, I could 'call' this a Duncan pup.

Then take my left hand and do the same thing, but 'call' this a PRS pup.

So to get a PRS and Duncan to play nice together, you have to flip a magnet (remove thumb and reinstall on pinky side of hand) OR, reverse the wires. (If I were double jointed I could curl my fingers backwards to represent the reversed current flow).

Thanks again Jim.

EDIT: Just read your last post Jim. I get it. You have to account for both variables in each pickup to determine the phase relationship. I guess I was hunting for the specific one that is different between a PRS and SD pup. Doesn't matter really. I just know that in the case of my neck #6 and CC bridge I had to reverse the wires. I could of flipped the magnet in one of the pickups to produce the same result.

Thanks much Jim!!

[Big Mike]

Great thread, thanks Jim!

Copying to the archives.