Some question about humbucker wiring,series vs parallel

[pazzpazz]

Two 4-h coil wiring in parallel,you get a 2-h humbucker,but two 1-h coil wiring in series,you also get a 2-h humbucker，Can I ask what the different between these two methods？Seems like when wiring in parallel，you get double the output？but what the downside？（using more wire？） sorry for my English

[newey]

pazzpazz-

Hello and Welcome to G-Nutz2!

Sorry, but I had to move your thread.

Can I ask what the different between these two methods？Seems like when wiring in parallel，you get double the output

No, series wiring will have more output than parallel. We often speak of the DC resistance of a pickup coil, but it is important to remember that DC resistance does not equate to output, it is an oversimplification we use as a handy "rough gauge" because it is easily measured with a multimeter. But, just for example, if a humbucker has 2 coils that measure 3KΩ resistance each, in series the resistances simply multiply, the resistance of both coils in series will be 9KΩ. In parallel, the formula is more complicated. Take their reciprocal values, add the two together and take the reciprocal again. For example, if one coil is 2 Ω and the other is 4 Ω, then the calculation to find the resistance of both in parallel is 1 / (1/2 + 1/4) = 1 / (3/4) = 4/3 = 1.33. In my example, with both coils at 3K, the parallel resistance of both is 1.5KΩ (my example was a simple case with the same value for both, but recognize that the formula is not "divide by 2").

So, in series the total series resistance is much greater (6X) than what the total parallel resistance is, but that in no way means the series output will be 6 times as much, there are a number of other factors that must be considered. Output depends not only on the pickups but on the circuit as a whole, and the interactions of all the components. There are many folks here that could give a much more technical explanation than I am able to do.

Just generally, parallel wiring will have slightly less output than series but will be a bit brighter sounding as well It will be closer to the sound of one coil of the humbucker, where "coil split" switching is used. But by wiring the 2 coils in parallel, we preserve the hum cancellation of the humbucker, whereas with the coil split we may have some single coil noise. So, some people prefer to wire a HB to switch between series and parallel rather than splitting the coils. I personally like the sound of parallel humbucker coils and so I have several guitars wired with a series/parallel switch.

Two 4-h coil wiring in parallel,you get a 2-h humbucker,but two 1-h coil wiring in series,you also get a 2-h humbucker

This part of your post is unclear, I think we have a translation issue. I don't know to what the "h" refers.

[pazzpazz]

Sorry, 2-h mean a coil that has a inductance of 2 Henry,I know if both coil are the same the series wiring will have more output,but what if you use 2 under-wound coil wiring in series compare to 2 over-wound coil wiring in parallel and end up with the same inductance,what the different between these two? Thanks

[Yogi B]

Rather than dealing in inductance which is approximately proportional to the output squared, it's probably clearer to talk about the number of turns in the coil (which is approximately directly proportional to the output), or even the just directly talking about the output level.

If we say your 1H coil has an output voltage V, then two in series would have output of 2×V. A 4H coil would have twice the number of turns as the 1H coil, so also an output of 2×V; placing a pair of them in parallel would keep that output level roughly the same.

Jan 13, 2023 5:39:47 GMT -5 pazzpazz said:

but what the downside? (using more wire?)

That is pretty much it, yes! The copper wire is probably the highest value raw material used in pickup construction. Note that it wasn't uncommon for Gibson copies to either use pickups with a really low number of turns or fake 'humbuckers' that in reality only had one coil of wire hidden beneath the pickup cover.

Other than pure cost you also have to consider that using more turns of the same wire gauge will take up more space, which could be impractical. Alternatively, thinner wire is more difficult to work with, for example: easier to snap.

Furthermore assuming you can still wind both coils at the same speed, twice the number of turns directly translates into twice as long to wind each pickup.

Leaving the practical considerations aside and thinking in terms of tone, the larger coil is likely to have more parasitic capacitance per turn (especially if using thinner wire). Additionally, combining the coils in parallel causes this to double, whereas it would be halved if combined in series. And, whereas usually parasitic capacitance is dwarfed by the cable capacitance, if it's being (at least) quadrupled then it could become a more important factor in limiting the treble response.

[ashcatlt]

Jan 13, 2023 9:17:05 GMT -5 newey said:

...in series the resistances simply multiply...

Uhhh...wanna try that again? They add. Around here, we use * as shorthand for series connections, as opposed to + for parallel, but that is very much a GNutz specific convention and has nothing at all to do with the actual math.

Ignoring certain of the esoterica such as actual coil size and parasitic capacitance (which yes will make a difference, but not enough to worry about in "back of the napkin" rough theorizing), 2 x 1H coils in series equals exactly the same 2H as 2 x 4H coils in parallel. If we're talking about just inductance, the difference we might expect to hear is a change in frequency response, and in this case there would not be expected to be any.

Now, if those coils are also 2 x 1K DCR in series, that's still kind of the same 2K as 2 x 4K in parallel. If we're just talking about resistance, the difference we'd expect would be broadband level, and (all other things being equal), I'd still expect them to be about the same, at least assuming that the ultimate load is bigger enough than 2K to be mostly ignored.

DCR by itself can't tell you anything about potential output, but in two coils which are otherwise the same, a higher DCR is expected to create hotter output because of Ohms Law, I think. The magnetic field creates a current flow. "The induced current depends on both the area of the coil and the change in magnetic field", nothing to do with the DCR. The voltage drop caused by that current flow is proportional to the resistance (V = IR), so bigger DCR gives bigger V for a given area of coil and magnetic field. Edit - actually that's weird and I'm not so confident in it, so let's not go there. It's more like when you put two batteries in series. If we call the bottom of one 0V, the top is (say) 9V. The top of the second is 9V above its own bottom, but if its bottom is on the top of the other, it is 18V above the first one's bottom. Or, to look at it a slightly different way, in series, both coils are pushing the same direction the same amount at the same time, so the force they exert is added together.

In the parallel case, though, the two coils actually form a voltage divider. If we consider just one coil as the source, the voltage it puts out is halved (assuming the two coils are matched), if the other is the source, it is also halved. They're actually both the source, and both are halved, and those then add together, so we're back to the voltage of just one of them on its own. But remember these coils were already double what we were talking about in the series configuration.

So it's kinda like 1 + 1 = 2/2 + 2/2

[newey]

Jan 13, 2023 21:41:30 GMT -5 ashcatlt said:

Uhhh...wanna try that again? They add.

Correct, my mistake.