Humbucker question

A recent thread in the electric guitar forum got me to thinking about humbucker theory. This thread was concerning single coils, matched sets of them & rwrp center pickups. At the risk of over simplification I understand that humbucker pups have 2 magnetic fields side by side with one usually being reverse wound, reverse polarity to achieve hum canceling. I also understand that a magnetic field isn't limited to the area around the magnet in question. But when you put a pup 2 inches away from another one, aren't you losing some or most of that hum canceling effect? Does it do much good to have the center pup rwrp? In a typical strat you only have 2 positions that would potentially be hum cancelling anyway. So is this more marketing hype or can you actually notice a difference? If it does make a difference, why not rwrp one of the pups in a 2 sc guitar? I've always used shielding paint & aluminum foil combined with good grounding and never had a bad hum problem. And my current rig doesn't have an rwrp center pup. It's the quietest "strat" I've ever had (left my amp on overnite, oops!). Comments?

The EMF that causes hum is traveling at the speed of light (more or less) so it arrives at both coils at the same time (unless you are a physicist) and so they can be quite a distance apart and still produce the hum-cancelling effect.

Having them too far apart introduces more wire - another antenna for hum.

The lack of hum from your guitar would make me guess that you probably have good shielding on your amp and no fluorescent lights in the room.

Customtele, The wire wrap and magnetic polarities are reversed.

Heres an explanation of what happens.

Humbuckers have a dual purpose they pass/create a signal using MMF and block EMF.

EMF is the bad stuff, its the radio waves given off by AC sources. Its not created by the working engine of a pickup. Its amplified/tuned in by it. Tuned coils in radios amplify and tune in EMF weather it be a radio station or just the AC band of radio 60hz.

A pickup generates a signal using MMF like a generator. The string passing in close proxcimity to a magnet and coil like a magnet passing through a coil generates voltage. Depending on which direction the string is traveling it will generate a + or - wave.

The bad stuff, the EMF is also picked up and amplified by the coils. The coils are wrapped in reverse to block that EMF. One coil generates a positive going signal the other a negative going signal. since these coils generate a mirror image of the AC radio wave at the exact same time, The two are 180 degrees out of phase so there is a null at that frequency and the hum is phased out.

The magnets and coils are reversed so the signal created by the strings are in phase. This signal passes out of the pickup unobstructed at double strength of a single coil pup.

To figure out how they cancel its more of a choke coil/phase canceling device and has less to do with the magnets themselves. The magnets could be just plain iron core transformers and still kill hum, (although they wouldnt produce any sound that way). Its just a tuned coil to block lower 60hz noise whils passing the higher frequencies that the pups produce.

You'll find these tuned coils in most Line filters you buy along with caps to remove high frequency noise. You also find them in power supplies to kill EMF and provide clean DC power. For more study on this you can read up on oscillators, tuned coils etc.

As far as your center pup on a strat being quiet, the center pup is going to be reverse phased with one of the HB coils when working with a humbucker. When its on by itself, its no different than any other strat. If its quiet it may be the shielding, wire length, that help keep it quiet as well as the number of turns on the coil. Put it in front of a CRT while plugged in to test it. A HB by its self will be the quietest, An HB and the single coil will have less than 180 degreed phase canceling because of the additional inductance of the single coil, and no EMF phase canceling by the single coil. With the single coil by itself, you rely on the guitar shielding and your body touching the strings to block the EMF that would results in hum otherwise.

Hope this explanation helps a littel.

It makes sense then that you will at least get some emf reduction with an rwrp pup in the center of a strat. I'm extremely anal about shielding my guitars and making sure ground loops don't exist. Could be most of the reason my latest creation is quiet. WRG your explanation also helps because the bridge pup in this app is humbucking. So the only time I would potentially have sc hum is in #3,#4 & #5 on a strat type switch as the center pup isn't rwrp.