How to Measure DC Resistance for Guitar Pickups
Overview – In this blog post I’m going to teach you how to use a multimeter to measure the DC resistance of a guitar pickup. I have a couple of different examples that I’m going to show you, and I’ve found that this is a skill that I use regularly as part of my guitar repair business here in Binghamton, NY. Hopefully this information will be worthwhile for aspiring luthiers, guitar techs, and guitarists who wants to learn more about the technical aspects of the instrument. Additionally, if you’re interested in watching as opposed to reading, I’ve created a video on this subject for my YouTube channel. So with that said, let’s get into it!
In order to do this you’ll need two things, one is a multimeter, and the other is a guitar pickup that you want to measure. One thing to note is that I am using an auto-ranging multimeter. If you have a manual multimeter you’ll have to set it accordingly. Typically, 20k will cover the vast majority of guitar pickups. Either way, we’re going to be using the ohms setting. You will take the black plug and put it into the negative common jack, and take the red plug and put it into the positive input jack.
First I’m going to show you how to measure the DC resistance of a single coil pickup. Take the black probe and connect it to the bare wire of the black lead coming off the pickup, and take the red probe and connect it to the bare wire of the colored wire coming off of the guitar pickup. When you do this you should see a measurement. Usually for Stratocaster pickups, 6K ohms is a fairly common measurement. One thing to note is that you can use the probes on either lead and get the same result. Personally, I like to have the black probe attach to the wire that I’m using for ground.
On a humbucker with two conductor wires, the process is very much the same as it was the single coil pickup. You take the black probe and connect it to the ground wire, and you take the red probe and connect it to the hot wire. In this example you can see a DC resistance of around 15.4k ohms. If instead of the red plastic casing you had a braided shield wire, you would simply connect the black probe to that in order to get a reading.
For a humbucker with four conductor wires, it can be slightly more complicated. Each pickup manufacturer has their own color code that shows which wires serve what function. If you want to measure the total DC resistance of a humbucker with four conductor wires, you’ll need to look up this code from the manufacturer for whichever pickup your measuring.
In this case I’m going to be measuring a Seymour Duncan style humbucker, and this is how you do it. You take the red and white wire and twists them together. You then take the green and bare wire and twist them together, and you leave the black wire by itself. You then take the black probe from the multimeter and connect it to the green and bare wire, this will be your ground connection, and you take the red probe and connect it to the black wire, which will be your hot connection.
Lastly, if you want to measure the DC resistance of a guitar pickup that’s inside of an actual guitar, you can connect a guitar cable and attach the probes from your multimeter to the sleeve and the tip of the jack. You can then use the selector switch to chose which pickup you want to measure. In the picture below, you’ll see I’m measuring the bridge pickup in my shop guitar that I upgraded extensively.
Anyway, that’s it for now! If you’re in Broome County N.Y. or the surrounding areas and need guitar repairs, feel free to message me here on my website by following this link to my Contact page where you can call me, email me or ask me questions. Thank you!
-David