Measuring Pickup Resistance

cjenrick

New member
After rewinding a few pickups I have noticed some funny things while checking the DC resistance of the coils.

These same things I first noticed while winding transformers.

If I wind a transformer coil and check the DCR, I get one reading.

After installing the coil onto the steel transformer core, I get a different reading.

This difference has been large or small, depending on the coil I use and the type of steel that is used for the core. A nickel core seems to make a bigger difference than the steel cores.

I was using a digital multimeter to make the DCR measurements.

As a hunch from the experiences I had with the transformer measurements, I decided to see if this also happens with pickups.

Sure enough, I noticed that measuring one coil of a humbucker before installing it onto to the magnets gave one reading, and after screwing it to the brass base plate and adding pole pieces, I get another reading. I know about the posts changing readings but this is without the pots soldered.

Also, if I measure two individual coils, I might get 4 K Ohms a piece. Then when I solder them in series and measure the resistance, I get a number that is a bit different than 8 K.

I have not tried using an analog meter like an old Simpson, but will try that in the future.

I was just wondering if anybody else has experienced this.

Maybe some of you DIY winders can try a few experiments and post results.

I wonder what type of meter Seymour Duncan uses.

Thanks!

cj
 
Last edited:
Re: Measuring Pickup Resistance

After rewinding a few pickups I have noticed some funny things while checking the DC resistance of the coils.

These same things I first noticed while winding transformers.

If I wind a transformer coil and check the DCR, I get one reading.

After installing the coil onto the steel transformer core, I get a different reading.

This difference has been large or small, depending on the coil I use and the type of steel that is used for the core. A nickel core seems to make a bigger difference than the steel cores.

I was using a digital multimeter to make the DCR measurements.

As a hunch from the experiences I had with the transformer measurements, I decided to see if this also happens with pickups.

Sure enough, I noticed that measuring one coil of a humbucker before installing it onto to the magnets gave one reading, and after screwing it to the brass base plate and adding pole pieces, I get another reading. I know about the posts changing readings but this is without the pots soldered.

Also, if I measure two individual coils, I might get 4 K Ohms a piece. Then when I solder them in series and measure the resistance, I get a number that is a bit different than 8 K.

I have not tried using an analog meter like an old Simpson, but will try that in the future.

I was just wondering if anybody else has experienced this.

Maybe some of you DIY winders can try a few experiments and post results.

I wonder what type of meter Seymour Duncan uses.

Thanks!

cj

What model of DMM are you using?
 
Re: Measuring Pickup Resistance

i cant speak to the transformers but i know when i wind a coil and check it as soon as im done and maybe an hour later when i check it again, it will have changed slightly. i assumed it was due to temperature difference
 
Re: Measuring Pickup Resistance

Measurements from an Epiphone LP Special 2 neck pickup:

Coils on base plate measured in K Ohms:

Meter A: 12.05
Meter B: 11.84

Pole Piece Screws removed:

Meter A: 12.31 difference: 180 Ohms
Meter B: 12.06 difference: 140 Ohms

Screw Pole Piece Coil removed from magnet and plate:

Meter A: 12.31 Difference: 260 Ohms
Meter B: 12.06 Difference: 220 Ohms

Meter A: Cheap Richmeter DMM
Meter B: Micronta 12-16

will repeat tests with fluke bench meter...
 
Re: Measuring Pickup Resistance

The presence of magnets, base plates, or pole pieces should have no affect on DCR. You aren't, by any chance, holding the probes with your fingers, are you? As opposed to using clip-on leads.
 
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