Understanding D.C. Resistance For Guitar Pickups

D.C. Resistance, or a pickup’s Ohm reading, is not the “Holy Grail” of understanding a pickup’s output – it will give you a rough understanding.

On occasion, we get a customer’s email stating that “their 8.2K Pure P.A.F. bridge reads 8K – What’s Wrong?” The answer is simply “Nothing at all.” There are a lot of variables that can make the same pickup provide different readings. However, there are more important things to take note of – at Fralin Pickups, we count turns rather than rely on ohm readings. Let’s learn a little bit about Ohm readings and what they mean for your guitar’s pickups:


Why Are Ohm Readings Important?

An Ohm reading shows the D.C. resistance of pushing electrical current through the pickup. It does not define the output of the pickup. The output of the pickup is affected by the number of turns of wire, and the magnet strength.

Ohm readings are a useful way of roughly measuring the output between identical pickup designs. This means comparing a Telecaster Bridge to another Telecaster Bridge, or a Stratocaster Neck to another Stratocaster Neck. For example, if you were to take a reading of a Vintage Hot Strat Neck (6K) and compare it to a Blues Special Strat Neck (6.3K), you’ll be able to confidently tell that the Blues Special will give you more output. This is true – the Blues Special has 5% more turns than the Vintage Hot, and roughly 5% more output.

The same applies to Humbuckers, which are normally measured by their ohm readings. A 9K humbucker will be higher output and louder than an 8K.

Ohm Readings tell you if a pickup works or not. If you test a pickup and get a reading, there is continuity in the coil – it works. If you get a reading of 0 Ohms, the pickup is shorted out. If the meter reads “Infinity”, the coil is broken somewhere and your pickup will not work.

Ohm readings can help diagnose problems. When we rewind pickups, we might get an old Strat pickup that has a reading of 50K, when it should read around 6K. We can use that information to tell that there’s corrosion in the coil eating away at the copper, giving it a point of high resistance. This coil would need to be re-wound to be fixed.


Ohm Reading Variations:

There are a few factors that can cause an ohm reading to fluctuate. Here are some of the most common:

  • Temperature: The hotter the pickup is, the higher the ohm reading will be. When we test a pickup when it goes into the wax vs. when it comes out of the wax all hot, the ohm readings are vastly different. Why? As the temperature increases, the ions in the copper wire vibrate more than they do at room temperature, thus collide more with electrons as they flow through the copper wire, giving the wire more resistance.
  • Length of Wire: See above! The longer the wire is (i.e. more turns per coil), the higher the resistance will be. This is how many users test guitar pickup output. Another example is a 5-String Jazz Bass versus a 4-String Jazz Bass. The 5-String Jazz bass is physically longer, and thus the same number of turns will result in very different ohm readings.
  • Diameter of Wire: 42 Gauge Wire (larger diameter wire) will have less resistance than 43 Gauge Wire (smaller diameter wire). For instance, we wind Telecaster Bridges with 42 Gauge Wire, and the Telecaster Necks with 43 Gauge Wire (the bobbins are smaller). Even though the necks have less turns than the bridges, they have a higher ohm reading due to the smaller gauge wire. That does not mean that the neck pickup is louder than the bridge pickup – it just means it has more resistance.
  • Testing Equipment: Depending on the manufacturer, quality, digital vs analog, etc. The way you test the ohm reading could have a significant impact on your reading.
Ohm Readings

These two multimeters are different styles and manufacturers, and are reading the same pickup. One reads it closer to 8.8K, and the other reads 10K.


COMMON MISTAKES WITH OHM READINGS:

The most common mistake we see people make when using Ohm readings is comparing two completely different pickup designs to each other. For instance, our Stock Pure P.A.F. set reads 7.8K in the Neck, and 8.2K in the Bridge. Our Blues Special Telecaster Neck also reads 7.8K – so they should be equal in output, right? Nope!

The design of the pickup and the amount of turns has the greatest effect on the pickup’s output and tone. For instance, the Humbucker might have two coils wired in series with 42 Gauge Wire, and the Telecaster Neck will have one tall, narrow coil with a 43-Gauge Wire. They might read the same, but their outputs and tone will be completely different.


OHM READING BRASS TACKS:

The number of turns is far more important than the Ohm reading of a pickup. If you got a Pure P.A.F. Neck that was reading 7.7K, rest assured that the correct amount of turns is on the pickup!

Always compare identical pickup designs. We can’t stress the word “Identical” enough – the slightest variation in design can really impact the ohm reading.

Call us when comparing different models. When comparing a Hum-Cancelling P-90 Neck to a Bridge Humbucker, we can narrow down the models that will work best. Call us. We’re here to help.

16 Comments

  1. Hi,

    I just built a 1-stringed pup modeled after 50s/60s PBass (10,000 turns…). I haven’t magnetized it yet, and am getting a 2.8k read. Does that seem right?

    Thanks!

    1. Hey Aimee,

      This really depends on the size of the pickup and gauge wire. Our P-Bass Coils read something like 7K each, with 42 Gauge wire.

  2. Hey, I own a player series sss strat and according to the factory specs the dc resistance of the pickups should be the following: Neck : 7.44k? , Middle : 8.00k?, Bridge : 8.5k?. When I measure the resistance at the same room temperature with the same multimeter etc. the neck and the middle pickups are quite close to the specs,but the bridge pickup is 500 Ohms less than the specs. The middle and the bridge pickups have the same dc resistance reading. I bought the guitar brand new two months ago and this reading seems quite off. Is this kind of variation covered by warranty?

  3. How would using thicker gauge wires to connect the pickups to the pots and switch affect the sound compared to thinner gauge wires? I’m not sure if I sure go thicker or thinner?

    1. Dan,

      I wouldn’t really worry about the gauge of wire as much as the resistance of it. I would take an ohm reader and take a reading of the start and finish of the wire. If you get a resistance reading, I would choose a different wire. The object is to have the least amount of resistance as possible, preferably none.

      Tyler

  4. Hey Tyler,

    I am building a Baritone Tele with a thinline ash body and a 28.629 neck
    250 pots and a .047mf cap
    So far I am planning on using Ernie Ball Baritone Slinkys 13-72
    I have read that higher output pickups can muddy up the sound.
    Can you please recommend a set of L. Fralin’s that should work for me.

    Thank you,

    Jack

    1. Hey Jack,

      I wouldn’t say “higher output” pickups muddy the sound, because adding a stronger magnet to a high DCR pickup can make it brighter and more articulate. I would say there’s a combination of things that can make it “muddy”, most importantly the design (a High Output Single Coil will not sound as muddy as a High Output Humbucker).

      Are you using Single Coils or Humbuckers? I would email our [email protected] for further assistance, or call the shop.

      Tyler

  5. I just buy a Telecaster 1972 and someone change the pickup.
    On the neck is a Dimarzio humbucker can be split in single with 5.75 ohms or 3.03 ohms in single.
    On the bridge is a single coil with 7.17 ohms.
    Combine with the switch on the middle give me 3.27 ohms for the humbucker+single and 2.18 ohms for the hum split in single+single.

    I want change the humbucker or it is just bad connect on the guitar?

    The sound on with the middle switch is too soft why?

    Maybe a other neck pickup with 7 ohm give me a better result…

    I can not check the magnet on the humbucker because the metal cap block possibility of a test .

    Thank you for your help

    1. Etienne,

      Cool name by the way. The middle position connects the pickups in parallel which will always give an ohm reading of less then the smallest resistance connected/used (approx 2/3 of smallest value). If you look for the article about resistors on this site it will provide you a formula to calculate these values. I did calculated your figures and got 3.2 (k im assuming) ohm im humbucking and 2.13 ohm split so your tele must have a mojo factor of 0.6 and many a story to tell :). Real world and theory are often not exact but should be reasonable close. Sounds like its just doing what it does. Always let your ears be the final judge, a lot of things we now consider beautiful in our world often started their life as a mistake (not always a happy one either). I would suggest a boost pedal because im that way inclined and contrary to what our parents/neighbours might say louder is better.

      Hope you have a good day and get to play the guitar.

  6. I am interested in replacing the p-90 in a Les Paul Junior I intend to buy with your noiseless one. What information do you need? Thanks.

    1. Hey Michael,

      It’s pretty straightforward. I would pick a Dogear Bridge, then select your output that you want (Stock, +5%, -5%). Gibson Lead will work fine. Gibson Spacing will be fine as well. The only thing I would suggest is to make sure you don’t need any shims. You shouldn’t, but double check anyway: Check it here.

  7. What would be the mostly likely culprit when one pickup position does have some output, but it is very, very low output?

    1. That could mean a couple things, Alan:

      1.) There could be some corrosion somewhere on the coil, leading to a very weak signal. If you attach your multimeter to your pickup and it reads something like 50-60K, then you know you have a spot of high resistance on your coil and you’ll need a rewind.

      2.) Bad solder joint. If the pickup reads fine, check your solder joints, especially at the switch.

      3.) Demagging – this one is a little more rare, but it’s a possibility. It’s possible you de-magnetized your pickup and it’s not as efficient as a fully-magged pickup. To check this, take a small screwdriver and tap each magnet. You want to feel the pickup’s pull as you pull away from it. If one pickup feels stronger than the other, you might have weak or demagnetized magnets.

      There’s a few more, but if you can’t solve it with the above mentioned remedies, I recommend taking it to a luthier.

      Tyler

  8. Re-send winding some mini humbuckers. Getting a 4.5 n 4.7 b.. what kind of result would that yeild for the player.

    1. Probably a very clear, very bright low-output tone. Most of ours come in at around 6K+, using 42 Gauge wire.

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