Why do humbuckers sound different wired in series or parallel?

GotMetalBoy

GotMetalBoy

Power User
I know when using 2 pickups at the same time, their positions cause phase issues, which causes comb filtering but why does a humbucker sound different when wired in standard series compared to parallel?

Up until a couple years ago, I played guitars with 2 humbuckers with a 3 way pickup switch. I hurt my back and left shoulder, so I had to find a light weight guitar. Someone recommended an Ibanez S or RG series, so I bought a low cost S521 and it had the tones I've been searching for the past 20 years. I really like the 2nd and 4th pickup positions. The 4th position is the neck humbucker in parallel. Why does it sound so different?
 
The two coils pickup different but similar signals. Some frequencies are canceled out, others are boosted. Depending on the pickup polarity and the pickup position this happens in different frequency ranges.
 
When a humbucker is run in series (standard wiring) both coils are added together (R1 + R2 = Rt). This means the pickup is at maximum output and will sound as dark as it can sound all by itself. In parallel the resistance of the two coils is divided (1/R1 + 1/R2 = 1/R3). This results in a humbucker with less output than series wiring and a brighter sound overall.

Generally speaking, the darker the pickup sound in series wiring the more noticeable the change will be when wired in parallel. The bright the pickup is in series wiring the less noticeable the change will be in parallel.

Bear in mind that resistance (a pickup's DC resistance) is not an accurate measure of its tone or output. The thickness and gauge of the wire used as well as the magnets will be better guide to its tone and output.

I've wiring hotter pickups for parallel (e.g. Dimarzio Tone Zone) and found the tone to be usable and much different than the pickup in series. Conversely I've wired a more vintage pickups (e.g. Dimarzio PAF) in parallel and wasn't thrilled with the result. It was usable but not a big enough tonal shift or output difference for me. That led me to just split the pickups (one coil only) which was much better as far as output difference (about half) and much, much brighter.
 
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Matt_B_77 said:
When a humbucker is run in series (standard wiring) both coils are added together (R1 + R2 = Rt). This means the pickup is at maximum output and will sound as dark as it can sound all by itself. In parallel the resistance of the two coils is divided (1/R1 + 1/R2 = 1/R3). This results in a humbucker with less output than series wiring and a brighter and less bassy sound overall.

Generally speaking, the darker the pickup sound in series wiring the more noticeable the change will be when wired in parallel. The bright the pickup is in series wiring the less noticeable the change will be in parallel.

Bear in mind that resistance (a pickup's DC resistance) is not an accurate measure of its tone or output. The thickness and gauge of the wire used as well as the magnets will be better guide to its tone and output.

I've wiring hotter pickups for parallel (e.g. Dimarzio Tone Zone) and found the tone to be usable and much different than the pickup in series. Conversely I've wired a more vintage pickups (e.g. Dimarzio PAF) in parallel and wasn't thrilled with the result. It was usable but not a big enough tonal shift or output difference for me. That led me to just split the pickups (one coil only) which was much better as far as output difference (about half) and much, much brighter.
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I know the formulas to add resistance in series and parallel but I thought when there's more resistance it causes less output? Do you know why speaker resistance causes the opposite? Example: An 8 ohm speaker causes more output than a 16 ohm. I figure this all has something to do with Ohm's Law, which I know all the formulas to find V, R, I and P when I know 2 of the values but I don't know what it all means.

I took one semester of basic electronics courses over 20 years ago in college but then I majored in bong hits and minored in alcoholism, so I didn't get very far haha o_O
 
GotMetalBoy said:
I know the formulas to add resistance in series and parallel but I thought when there's more resistance it causes less output? Do you know why speaker resistance causes the opposite? Example: An 8 ohm speaker causes more output than a 16 ohm. I figure this all has something to do with Ohm's Law, which I know all the formulas to find V, R, I and P when I know 2 of the values but I don't know what it all means.

I took one semester of basic electronics courses over 20 years ago in college but then I majored in bong hits and minored in alcoholism, so I didn't get very far haha o_O
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Together with the resistance also the output voltage changes. Think about batteries: If you put 2 in series, the voltage doubles, if you connect them in parallel, the voltage stays constant.

And there's one main difference between a speaker and a pickup: The speaker consumes energy, the pickup produces energy.
 
A pickup is basically a 2nd order low-pass defined by the wire resistance, the coil inductance and its capacitance. The more turns the higher its resistance, inductance, and capacitance causing a lower cut-off frequency of the low pass.
 
Also the resonant frequency (cause mostly by cable capacitance with coil inductance) is about double, giving a sound similar to what people describe as "chime" in single coil pickups.
 
Matt_B_77 said:
Bear in mind that resistance (a pickup's DC resistance) is not an accurate measure of its tone or output. The thickness and gauge of the wire used as well as the magnets will be better guide to its tone and output.
Click to expand...

Ok I gotta jump in and correct this just a little bit because you kinda contradict yourself. I mean you're pretty doggone close, but... Gauge and thickness are the same thing (you may have meat to say thickness or gauge, so I'll give you the benefit of the doubt on that). Resistance is a function of gauge/thickness - and really the concept you're going for here is the cross-sectional area of the wire face multiplied by the length of the wire.

wire-diameter-resistance-600x191.jpg


giving us a formula:

latex.php


Where R is equal to the length of the wire (l)divided by the cross-sectional area (a) multiplied by a material constant (p).

Source: My 2nd semester college physics notes and this website for the images:
http://www.itacanet.org/basic-electrical-engineering/part-2-resistors-and-resistances/
 
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