RWRP question

Gearhead

tonerider wrote: For those of you want to know - RWRP simply means reverse-wound-reverse-polarity. To simplify even further, when a single coil pickup is wound during manufacturing the wire can either be turned around the bobbin in a clockwise or anti-clockwise fashion. In a twin-single-coil guitar like a Tele either one of the pickups must be RWRP to effect noiseless operation in the middle position of the 3-way toggle switch (the 2 pickups [electro-magnetic devices] are then placed in parallel) . When used on their own it becomes irrelevant whether clockwise or ant-clockwise and either way the sound will be the same. The same applies for the middle pickup on a Strat. If reverse wound you will have noiseless operation in positions 2 and 4 of a 5-way toggle, yet the middle pickup on its own will sound the same whether clockwise or anti-clockwise wound. (Tele: +- -+) (Strat: +- -+ +-)

tonerider wrote:
Gearhead wrote: ...and the RP stands for flipping the magnet 180 degrees so the magnetic field is also reverse. A positive swing of the string now has the same electrical effect on the output of both pups.
Hi Gearhead, just remember that the term RWRP is usually referred to when dealing with single coil pickups. The RP means that polarity is turned 180degrees through the actual winding of the coil and has nothing to do with the magnets (pole pieces/slugs) that are permanently pressed through the flatwork.

You're actually referring to flipping the magnet though its width under the bobbins of a humbucker. Although this does change the overall polarity of the humbucker (often an easier job to accomplish for someone not familiar with a soldering iron and wiring) the coil windings remain as originally wound. This is normally done when a humbucker is out-of-phase with another one, such as on a Les Paul style guitar.

That's interesting. So what you are saying is that an RWRP single coil pup is firstly wound ccw as opposed to cw (or vice versa) and subsequently the leads are swapped? To me that sounds like you wind up with the same thing (no pun intended).

MikeM

You are correct Gearhead. The direction of the wind is not really relevant as swapping the leads will just reverse the wind. You and I have noticed that on more than one occasion ?

The polarity of the magnets has to be reversed. A RP pup will attract similar sides (Bobbin to bobbin or stagger to stagger) HB and single coils are the same this way, except you can't really swap the magnets on a single coil without destroying it.

Gearhead

... so you build it that way, right? Glad the pro's can clarify this ?

edit: with all due respect, this was a joke, ok?

AlanRatcliffe

The RP means that polarity is turned 180degrees through the actual winding of the coil and has nothing to do with the magnets (pole pieces/slugs) that are permanently pressed through the flatwork.

I beg to differ. The coil is RW (Reverse Wound) AND the magnets are RP (Reverse Polarity). As both are opposite compared to their counterparts in the other pickups, the polarity of the output signal from the pickup remains in phase with the outputs of the other pickups. Changing only the winding direction would reverse the polarity of the pickup's output, so it would be out of phase with the polarity of the other pickups.

[EDIT - I type too slow]

Gearhead

Alan Ratcliffe wrote: [EDIT - I type too slow]

Try taking both hands away from the guitar at the same time, type using both ? ?

tonerider

Gearhead wrote: That's interesting. So what you are saying is that an RWRP single coil pup is firstly wound ccw as opposed to cw (or vice versa) and subsequently the leads are swapped? To me that sounds like you wind up with the same thing (no pun intended).

Hi Gearhead, it appears that you are a bit confused. If you swap the leads around on a single coil pickup you are merely making that pickup go out of phase with the ones adjacent to it. (assuming a matched "set")

It is not the same thing.

Reverse winding is a fundamental design property. Let me explain - say you have three single coil pickups on a Strat. By looking at traditional pickup wiring you will find (for example) that the three coils in front of you will be wound left-over-right, left-over-right, left-over-right, from the bottom inner part closest to the flatwork. In position 2 & 5 of the toggle the pickups will sound normal, but will be prone to noise, just as if they were played on their own. However if the middle pickup were to be wound right-over-left, in the notched positions the pups will still be connected in parallel and "in-phase" and the magnetic pole piece slugs will continue to have the same polarity as the other pickups in the set (yet mounted "upside-down"). Yet due the fact that one of the coils is wound in a anti-clockwise fashion around the bobbins will give an effect similar to that of a humbucker's two coils that are wound in-series but out-of phase with one another (which allows for bucking the hum). Take note that RWRP does not make for a "humbucker" sound, but only cancels the hum.

So, in a nutshell, changing the leads around on a single coil pickup is not the same (and has a completely different effect) as winding the coil in an opposite direction around the magnet slugs.

Bring it on guys, I'll try my best to clarify this very interesting topic. I've repaired and wound numerous pickups myself and have experimented with coil tapping techniques and winding methods for 30 years now. I don't do it anymore since it's just way too time consuming.........and I have these "other" pickups now. :?

Hope this sheds more light!

André

AlanRatcliffe

MikeM wrote: You are correct Gearhead. The direction of the wind is not really relevant as swapping the leads will just reverse the wind. You and I have noticed that on more than one occasion ?

Either will work, but the reverse wind is a standardised way of doing it across different manufacturers and ensures simple wiring with the same eyelets used on each pickup. Less chance of making mistakes.

you can't really swap the magnets on a single coil without destroying it.

Most of the time with Strat and Tele single coils, yes. I've swapped the magnets around before, but with a 50% failure rate, so wouldn't do it on an older pickup. Occasionally it's a ceramic magnet and some designs use a bobbin - not usually though ?

Gearhead wrote: Try taking both hands away from the guitar at the same time, type using both ? ?

Busted! LOL!

tonerider

I would probably be better to discus this topic on the appropriate forum but I don't know how to migrate this to there. Alan?

Gearhead

tonerider wrote: Hi Gearhead, it appears that you are a bit confused.

I'm not. One can actually look up http://en.wikipedia.org/wiki/Maxwell%27s_equations and work it out oneself: E = i x B so the direction of the current is what counts. So winding ANY coil the other way and then flipping the leads is the same. As Alan pointed out, it should be easier for the manufacturer to reverse wind than to change leads.

AlanRatcliffe

tonerider wrote: I would probably be better to discus this topic on the appropriate forum but I don't know how to migrate this to there. Alan?

OK. Gearhead made this new topic here already. I've merged the two topics together now.

tonerider

Gearhead wrote:
tonerider wrote: Hi Gearhead, it appears that you are a bit confused.
I'm not. One can actually look up http://en.wikipedia.org/wiki/Maxwell%27s_equations and work it out oneself: E = i x B so the direction of the current is what counts. So winding ANY coil the other way and then flipping the leads is the same. As Alan pointed out, it should be easier for the manufacturer to reverse wind than to change leads.

Hi Gearhead. I have to say that you're contradicting yourself. Yes, current flow is what counts. This is WHY the coil is reverse wound. The leads are not changed and the start and the end of the coil is affixed to the same points and the same wire color coding is used as the ones adjacent to it. Yet the current (in Millivolts) is flowing in an opposite direction in relation to its magnetic pole pieces (factory installed upside-down to the others in the set) and when placed in parrallel to a clockwise-wound pickup it will reduce hum. It's much simpler than you think!

André

{PS: don't believe EVERYTHING you read on Wikipedia, it is mostly written by the general community]

tonerider

Hi Gearhead, if I have confused you about magnets, its because I've misunderstood your question and for that I apologize! Indeed you can't change the polarity of the pole piece slugs of a single coil pickup by changing the direction of the coil wiring around the bobbin coil, you have to actually turn the slugs around, and this is very hard to do without damaging the pickup, yet it CAN be done. I've eventually succeeded after destroying about 4 perfectly good pickups, but this was a number of years ago and I won't do this work anymore.

I've seen this saying on some guitar site and love it "how many guitars do you need? - just one more!"

tonerider

One cannot change the polarity of a magnet - period! ?

AlanRatcliffe

tonerider wrote: One cannot change the polarity of a magnet - period! ?

Ferromagnets can be both magnetised and degaussed. So no big thing to change the polarity. Not usually done, but still possible.
http://en.wikipedia.org/wiki/Magnet#Magnetization_and_demagnetization

tonerider

Alan Ratcliffe wrote:
tonerider wrote: One cannot change the polarity of a magnet - period! ?
Ferromagnets can be both magnetised and degaussed. So no big thing to change the polarity. Not usually done, but still possible.
http://en.wikipedia.org/wiki/Magnet#Magnetization_and_demagnetization

Hi Alan,
I know!.......and there are those who will go to any length to degauss and re-magnetize magnets. I suppose some can get blood from a stone, but in my view it is an irrelevant and time-wasting exercise in relation to single coil pickups and best left to the extremists. Just go and get a new one! ? I mean, an Alnico pole-piece slug has a positive end and a negative end (North and South) and this will remain so irrespective of which way you turn it or the direction the coil happens to be wound.

nicovlogg

Now I'm pretty confused - the middle pickup on a strat is then out of phase thanks to the winding first, then secondly thanks to the wiring, which puts it back in phase with the bridge and neck pickups?

Gearhead

No, it is electrically out of phase because of the windings and magnetically because of the magnets. It will therefore cancel some of the hum and still be in phase.

AlanRatcliffe

Let's see if I can explain this so it makes sense:

It's similar to the way the two coils of a humbucker work to cancel hum. The middle pickup's coil is the opposite polarity to the other pickup's coil. This means that signals generated in the two coils end up out of phase and cancel each other out when added together. This would usually cancel the guitar sound too, but the clever bit is that the magnets in the middle coil are also reverse polarity, which also swaps the polarity of the signal induced in them by the strings. So the polarity of the guitar signal from the middle pickup is reversed twice (once by the magnets, once by the coil) and ends up the same phase as the signal from the other pickups.

The unwanted hum induced in the two coils by stray magnetic fields bypasses the pickup magnets, and is only reversed once by the middle coil, so when the two signals from the pickups are added together, the hum from one pickup is out of phase with that of the other and they cancel each other out.

nicovlogg

Alright, now I get it ?

Does the distance between the two pickups affect how well hum is cancelled?

Gearhead

It does, you are getting the point indeed. The cancelling effect is only achieved completely if the electromagnetic interference hits both pickups at the exact same phase and intensity. Otherwie, it will only cancel out partially - so 'buckers are better at 'bucking. As they should.