bugged SD diagram, or am I nuts?


Master Member

Seems like this diagram from Seymour Duncan is poorly thought out, due to something Dimitri pointed out.  If you split the coils and put the 3-way in the middle position, you'll have the "north" coil on each humbucker, which have the same polarity, so you'll get lots of hum.  It'd be like putting a non-RWRP coil in the middle of a Strat... the hum would be doubled instead of cancelled.

So I'm pretty sure the correct way to wire this is to change the bridge pickup wiring so its "south" coil is used for the coil tap.  Swap the green and white wires, and swap the black and red wires.

Seems weird that SD would put something like this on their site... am I nuts here?  Am I just stupid?  (Alfang, what do you think?  ;))
Haven't used that particular circuit, but in a similar configuration in which I have BOTH the volume and tone setup up as push/push coil taps for a RG TX/BBQ set I don't get any major hum if I have both coils tapped and put the 3 way in the middle position. That being said, I rarely use the coil taps and most typically do when 3 way is switched to one PU or the other; RARELY ever have used "both" pickup position on 3 way on any guitar/pickup config other than stock ES335 and Thinline with BluesBar/Fat Bastard PUs.
I think the schematic is fine, I can't imagine where this hum is gonna come from, The poles don't matter, the direction of each of the split coil that is active, is wound in the same direction, assuming the pups were close enough.,,,the windings are opposing each other at their nearest to each other side. so they are in fact just like a wide humbucker at that point.

dbw  I really am glad that you are figuring it out, sorry I was so harsh on your previous pickup wiring post. Part of what will help you master your schematics is doing exactly what you are doing, picking them apart.

I have yet to see a bad SD schematic, that doesn't mean they aren't out there, I just haven't seen one yet

i don't think your nuts. i beleive the polarity or maybe phase would be more apropriate of the hum that it picks up is based on the winding direction of the coil. i don't think the magnet efects the hum at all. to cancel the hum you need 2 coils to put out oposite hum ie. oposite winding direction. it has nothing to do with what is ajacent to the p/u or what direction that coil is wound, only the distence,  winding direction, symetry(are the coils exactly the same?) and posibly the angle of the coils that are on. so i don't understand what point alfang was trying to make.

i think seymour duncan knows their stuff. they have good pickups for any type of music and the best technical information. i'd assume that it its written that way to not confuse the amateur's that might buy the pickups. also how often will you have both coils tapped and used at the same time? that might sound pretty thin. also hoy much will it really hum? i have guitars with single coils, even hot ones. i don't normaly find hum a major issue. if i have the gain very high i'm going for a sound that is better for a humbucker anyway.

and i'm not sure it will increase although i may have said that in the past. when 2 pickups are wired in paralell the voltage wont add up.
in theory the current will increase but how much? the pickup isn't a significant source of resistence in the guitar curcuit compared to a 10M ohm input on the amp or a 500K pot. when all is concidered the impedence can't be that high at 60hz so the current won't change much.
but the current doesn't even matter. the apm is a voltage sensitive device.
there may well be some other factor i missed or don't have knowledge of but IMHO i don't still think the hum will add up.

if you read the duncan support section it has endless discusions on phase and how to wire your guitar with in depth information. even info specific to other brands and oems.
also if they had a "bad" schematic i'm sure somebody has let them know and they fixed it.
Thanks for your comments, guys.  I'll take a look at the SD site in more depth and I'll do some testing.  Stay tuned :)
Dimitr33  the windings on a humbucker are wound in the same direction, so that the current in the coils closest to each other is passng in opposite directions, the expanding and collapsing field buck each other and cancels noise, It's a lot like Cat-5 cable, any noise on one conductor is cancelled by the noise on the returning or adjacent conductor.

if the coils are opposite wound then the entire signal on one bobbin is fighting against the other, and that gives you that thin "outta phase" sound

You can wind them opposite, but you need to wire the leads so that the current in both is traveling in likewise direction, clockwise or counterclockwise--so the current in the middle of the humbucker is in opposite directions

it seems you are talking about out of phase wiring, theres a big diference between hum cancelling and out of phase, some people like out of phase, I personally don't like it. Hum cancelling has everything to do with how close the coils are to each other.

Proximity of adjacent pickups will play a part in weather or not they aid each other in hum cancelling. so disdance is a factor. A bridge and neck pup are probably too far apart to hum cancel.

So I don't understand what point YOU are trying to make.
the direction cc or ccw as it is viewed by coil start to coil finish can vary. but if you look at it from ground to hot the will always be oposite each other! PERIOD! only if you wanted out of phase wireing would you do it the other way.

the oposite wireing and how they fight each other is the idea, the hum fights itself! the output of the string vibration is electrically in phase due to the oposite magnet polarity. oposite mabnetic polarity is inevitable in a humbucker as the poles share a common magnet.

i'm not talking abut outta phase wireing, a humbucking effect needs oposite magnet polarites on the to coils to get an in phase signal do to the fact that the winding direction is oposite. hence the rw/rp midle pup on a strat. it is the magnet that is the oposite polarity that they are refering to as oposite coil polarity is implied by reverse wound.

this is directly off the seymour duncan Q/A it is mentioned many times but this is the first one i found.

"74. What difference will there be if you wind a pickup Top Coming or Top Going?" Robert A. Hulem, Hamburg, New York

    "Starting with a typical Vintage Stratocaster the coil is wound Top Left/ Top Going. If you look at a top view of a stock Fender Stratocaster pickup, eyelet's at 6:00 O'Clock and the cover removed you will see the beginning coil wire starting on the lower left eyelet and the coil winds clock wise around the bobbin and finishes on the lower right eyelet. If two or more coils are wound in the same direction with the same magnetic field they will be in phase. If one coil is wound Top Left/ Top Going (clock wise) and the other coil is wound Top Left/ Top Coming (counter-clock wise) with the same magnetic field the two coils will be out of phase. If one coil is wound clock wise and the other is counter-clock wise with two opposite magnetic fields the pickups will be in phase and HUMBUCKING. I would keep the coils wound in the same direction if you don't have any means of re-magnetizing the pickups. If the pickups you are using have two different magnetic fields (after market pickups) then it would be best to wind in opposite directions."

i'm sorry to burst your bubble here and i mean't no disrespect but i rarely say something without haveing a bit of an idea of what i'm talking about. and when i do make a mistake, and it happens i can recognise it. when i do make a mistake i expect it to be pointed out but this is not one of em.

your right proximity means something. if the noise enters the coils at diferent points in time it will change whether it is hum canceling. but 60hz at the spead of light is a pretty long distence. i don't think your guitar is that big.

i learned this years ago buy reading dan erlewine's book. so there is another professional that agree's

let me reiterate
a humbucker cannot have current going in the same rotational direction do to the oposite magnetic polarities of the pole peices. it just wont flow the same way. the hum however is not effected by the magnetic polarity. it will flow in the same direction regardless. it does not buck the hum by the interaction of the ajacent coil in the way you think. wireing the two coils in a way that looks out of phase puts the hum out of phase. that is why we switch magnetic polarities. so only the hum is out of phase.

if your oposite direction at the surfaces adjacent to each other theory was correct why would it only cancel hum? why not the signal too?
why would it not happen in a single coil? the neck side of the coil would move from bass string to treble and the bridge side of the same coil would go treble to bass right?
are the two sides of the same coil not adjacent?
if a neck pickup were too far from a bridge pup to effect each other then why bother having rwrp neck pups for a tele?