Mystery Pickups

I wanted to largely use parts that I already have for the first stab at the wiring arrangement that I want. Luckily I have a set of humbuckers sitting around and 500k pots to wire them up. There was just one small problem. The pickups contain no clear brand markings, only indicators which one is the neck and which one is the bridge pickup. Since pickup manufactures don't standardize on the wire colors, not to mention I have no idea the brand, I need to figure out the wires for myself.

http://www.neighborhost.com/scrapbook/pickup-id.html

Using the technique above, armed with my trusty multi-meter, I went to town.

The pickups have four wires. Each humbucker has two poles (north and south), with a pair of wires being the start and finish for each pole.

The first step is to determine which wires belong to each pole. Doing so is straight forward. Using the resistance (ohms) setting on the multi-meter. If a pair of wires has a measurable resistance (should be in the 5k - 15k ohms range), then they belong to the same pole. If the pair of wires has infinite resistance, they belong to different poles. Performing this test shows that the black and white wires belong to one pole and the red and green to the other. I was measuring ~12k Ohms per pole. Looks like they are hot pickups!

The second step is to determine which pair of wires belong specifically to the south pole and which pair belong to the north pole. With the multi-meter hooked up to the black and white wires, set in DC volts mode, tap a screw driver to each of the poles. If you see a spike on the multi-meter, then you have the wires for the pole in question. If you don't see a spike, or more likely, a much reduced spike when compared to the other pole, then the wire pair you are testing do not belong to the pole. Performing this test shows that the black and white wires belong to the south pole (the one with the visible screw lugs) and the red and green wires belong to the north pole.

The third and final step is to determine which direction is correct for a series wiring. Using the screw driver tap above, observe which direction the needle on the multi-meter moves as you tap. You want the south and north poles to move in the same direction. The article at the top of this posting seems pretty sure that the reading must be in the positive direction as you tap and negative as you pull away. I'm not sure it matters that much, but I'm going to use that convention and give it a shot.

After this whole procedure, I get the following wire assignments:

• South Pole (screw lug)
• White -
• Black +
• North Pole (covered lug)
• Green -
• Red +

If I perform a mapping to known pickups (say Seymour Duncan), commonly available wiring diagrams can then be applied to these pickups.

You may be asking, why use unknown pickups on a custom built guitar? At this stage I'm more interested if my unconventional wiring ideas are actually viable than the sound of the pickups. But that is a topic for another post...