Determining a pups polarity without installing it

[rmcfee]

There must be a way to test a pups polarity without going to the trouble of installing it to see if it will hum cancel with another pup?
Would a compass do it. Pickup scientists unite! Thanks - Rob McFee

[jmutations]

Re: Determining a pups polarity without installing it

An easy test is to hold the pickup above its proposed mate upside down (pole to pole, bass side to bass side) The two should stick together rather than repelling each other. Opposite magnetic coils (which attract) will hum-cancel. It may take some fiddling with the wiring to get the phase correct, but your polarity should be there.

[ArtieToo]

Re: Determining a pups polarity without installing it

I'm not so sure that would tell you anything. It would certainly mean that the magnets we're reversed, but what if the coils were wound reversed?

A pup could pass your magnet test, and still be out-of-phase with another.

I don't think there's any good way to do this without installing them. For one thing, to check phase, they'ld both need the same stimulus, at the same time, as in a string vibrating.

You could, of course, build a p'up phase tester by mounting a single string on a good stiff board. Slide the two pups under it and pluck the string. The problem with this is, it still means you'ld have to remove one pup from the guitar in order to compare two.

There's just no easy way around this.

[dr.barlo]

Re: Determining a pups polarity without installing it

ArtieToo is right. (of course when both of the HB are in full mode, no probles there because each of them wash the others reverse wound coils themselves.) But to some extent so is jmutations. Because generally we are talking about HBs from the same manufacturer!

Often I change the magnet of a HB that I am already using. Then when I take the magnet off, I am very careful to remember the way I pulled it out. The new magnet should have the same polarity as the one that just got out. So they should push each other. Works for me!

But when such a test needs to be done from scratch, as ArtieToo said, apart from some moderately costly ways (getting a polarity tester from StewMac), the only thing to do is to install them and hear the results for yourself.

B

[sanrafael]

Re: Determining a pups polarity without installing it

Jmutations has it right. You have to know if the magnets are reversed, and that is easy with his test. You need two coils with opposite magnets to make a humbucker. You do not have to put the pickup in the guitar to determine the coil polarity. Wire the pickup to a cable, plug it into your amp and listen, and then reverse the wires on one coil; does it hum more connected one way or the other? If you have the magnet polarities reversed on the two coils this has to tell you right way to connect it.

[Lightning]

Re: Determining a pups polarity without installing it

Jmutations has it right if your talking about 2 SD HBs but there are some variations coil starts between manufactures. SK guitars has a good list regarding this.

I would definitely test with ears for phase and hum with both pickups on before adding additional switching.

Mirror PU leads if there is a phase issue. Move slug bobbin to screws and visa versa for the screw bobbin then follow Jmutations instructions for mag polarity in hum has occurred.

Chuck

[mongrollo]

Re: Determining a pups polarity without installing it

Another way, related with Jmutations method, it is to use a normal magnet. The same pole of this magnet has to behave in the oposite way in the two sigle coils you want to test. Then you just have to deal with the hot and ground conections. The problem comes if both pickups doen't have the ability reverse phase (like the braided conectors). If only one can be reversed and magnets are in oposite direction then everything will work just fine.

[ArtieToo]

Re: Determining a pups polarity without installing it

Kinman explains on his site how the use a meter to determine phase . . .

Thanks Kent. Great website. I'll have to add that to my "links" webpage.

[dr.barlo]

Re: Determining a pups polarity without installing it

And secondly, Barlo ... any word on that seven way switch yet? I PM'ed you but never heard back yet? Later.

Did not hear anything from the man yet. I sent an email, and no replies! But he will eventually come back.

B

[Kent S.]

Re: Determining a pups polarity without installing it

Did not hear anything from the man yet. I sent an email, and no replies! But he will eventually come back.

B

Just checking,as that would open a few more tone possiblities, thanks again B!