Understanding DC Resistance

DC Resistance (DCR) is the main specification that pickup manufacturers use to describe the construction of their models. Electrically, resistance describes how easily electricity is conducted by a material. In pickups, it is referring specifically to the resistance of the wire within the coils. It does not account for the pickup’s design or magnet. It is also not entirely correlated with output. This makes it difficult to use as a predictor of the pickup’s sound. DCR measurements can even change based on the temperature they are recorded at. DCR will always vary slightly when measurements are taken, and shouldn’t be expected to be exact.

More importantly, wire gauge influences DCR heavily. Pickup wire is measured in AWG (American Wire Gauge). Common wire gauges used in pickups are 42 AWG, 43 AWG, and 44 AWG – 42 AWG being the thickest, and become thinner as the number increases. As the wire gets thinner, the resistance per foot increases. This means that two pickups with the same resistance, but different wire gauges, will contain a very different amount of wire. This means they will sound very different. See the images below of the DiMarzio PAF 59, which uses 42 AWG, and the DiMarzio EJ Custom, which likely uses 44 AWG. Notice how filled each bobbin is, even though they have similar DCR measurements.

DiMarzio PAF 59 Neck, 8.2K (42 AWG)
DiMarzio EJ Custom Bridge, 8.0K (~44 AWG)
 DiMarzio PAF 59 NeckDiMarzio EJ Custom Bridge
Wire Gauge42 AWG~44 AWG
DC Resistance8.2 K8.0 K
MagnetAlnico 5Alnico 5
Inductance4.4 H2.2 H
Resonant Peak3.0 kHz4.3 kHz

Looking at the resonance curve, we can see that they are vastly different pickups:

One of the reasons multiple wire gauges are used is to increase available space for more wire turns. Increasing turns increases the output of the pickup by increasing inductance. The reason most PAF-style humbuckers are around 8-9K is simply a matter of space – it’s close to the total amount of wire that can fit on the bobbins. In contrast, a Seymour Duncan JB uses 44 AWG and can fit significantly more wire on the bobbins.

Increasing inductance also comes with the trade-off of decreasing the resonant peak. In some situations this is preferable. In others, it may be detrimental.

Lastly, let’s compare a standard PAF, medium output, and high output humbucker from Seymour Duncan. Each of these contains 42, 43, and 44 AWG respectively. Otherwise, their construction is similar.

 Seymour Duncan JBSeymour Duncan PegasusSeymour Duncan 59 Model
Wire Gauge44 AWG43 AWG42 AWG
DCR16.4 K12.1 K8.5 K
MagnetAlnico 5Alnico 5Alnico 5
Inductance8.3 H6.1 H5.0 H
Peak2.0 kHz2.4 kHz2.6 kHz

To use DCR with any reliability, it must only be compared with other pickups of the same construction and wire gauge. When these are accounted for, it can be an estimation for total wire on the bobbins, which can translate to output and an estimated resonant peak. Even still, this does not account for asymmetrically-wound humbuckers. Fortunately, most pickups of similar types (PAFs, vintage strats, high output humbuckers, etc) typically use the same wire gauge. Using DCR within a category is generally a safe assumption, but not a rule.

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