So what exactly does reverse-phasing do to guitar pickups?

[DaveGrima]

Im gonna do this to a couple of my guitars to get extra tones. I dont really understand what it means to get pickups "out of phase"

[Bignasty006]

Im gonna do this to a couple of my guitars to get extra tones. I dont really understand what it means to get pickups "out of phase"

 

Always sounded like an lo-fi kind of tone to me. Not sure what it "does" to the pickups though.

[WRGKMC]

Not much to one pickup by itself.

To understand what happens you get down to a basic electric genarator.

the mast simple being a coil of wire and a bar magnet.

Hook the meter to the coil and push the magnet through the open coul and you get a positive

voltage generated. Pull it out and you get a negative voltage. Do this quichly and you gave AC voltae.

 

Swap the leads around and instead of getting a positive voltage whan you push the bar magnet into the coil, you get a negative voltage,

and when you pull it out, a positive voltage. Basic voltage genetration through magnatic field induction 101. The magnat lines of force cut

across the electrons in a wire and force them to move in one direction or the other depending on the polarity of the coil "Or" the magnet N and south poles.

 

A pickup does the same thing except the magnet and coil are stationary, and the strength of the magnetic field is varied by having a piece of steel

within that magnetic field varying the magnetic strength.

 

When the string is plucked and it vibrates down, It may make a positive going wave, and when it vibrates back up it may make a negative going wave.

Since say an open E string moves at 82 vibrations per second, its generates a positive then negative going AC voltage signal.

 

Heres where your question comes in. If you reverse the two leads of the coil - Instead of the wave going positive first, it goes negative first.

"OR" if you use swap a south pole magnet instead of a North pole magnet - the signal will go negative first.

{"Or" it will go negative first if you pluck up first on a string instead of Down}

 

With a single coil you dont hear a difference in sound for all intents and purposes because the first negative or positive going wave

is only 1/82 of a second long.

 

Where phasing does come into play is when you have two pickups of equal strength, placed side by side and one either has a reversed magnet

"Or" a reversed coil. When the string is moving down across the two coils one generates a positive wave and the other makes a negative wave at the same time.

 

The two signals are equal and opposite so no voltage is generated in the wire. The two cancel each other out and you get zero AC voltage.

Thats whats called phase cancellation.

 

There are situations of course where the pickups are separated farther away on a guitar. The amount of the string vibration is different so the two

coils generate a different amplitude signal. The Pickup that generates a stronger positive and negative signal will not be completely phased out

by the other pickup so some sound comes through. It will often sound thin and nasaly because the bass frequencies which are the largest get canceled

first, and is different overtones occur at different parts of the string, they get through without cancellation.

 

Thats about it in a nutshell.

As an extersion of this, a Humbucker has one coil that has both a reversed magnet and a reversed coil.

The second coil does generate a positive going signal at the same time the other coil does, so the signal generated

by the string, is in phase. What happens is if stray AC radio waves get close to the pickups and the pickups act like

antennas and generate a voltage straight from the air, One coil generates a posive going wave from the hum, the other coil

generates a negative wave and the hum is canceled out. Both coils again need to have the same amount of winds and equal inductance

to full cancel the AC hum. The magnets have no influence on the hum other than them being made of metal which increases

the strength of the inductance.

 

So in a nutshell, the two coils being equal and opposite cancel stray EMF through reverse phasing and signals they both generate from a string

are in phase.

 

One other item that goes beyond the basics. I dont want to go too far on this because you may still be wrapping your head around

the "ideal" theory of signal generation in transducers, But a single coil can sound "mildly" different when reverse phased.

When I mean mild, an average ear may not detect it and its so small it doesnt amount to a hill of beans in most cases.

Coils are resistive, they do have capacitence and they are inductors. There are things like capacitence that can occur within the

coil that can alter the signal a little.

 

By reversing the coils polarity, it can change the amount of capacitence so there may be a slightly brighter sound from the

pickup when its wired one way or the other. This isnt something you'd just do willy-nilly though.

Most single coils are marked positive and negative for a reason

 

The negative grounded lead is normally connected to the outer wrappings of the coil.

and the positive side is connected to the inner end of a coil. By doing so, the outer grouned wrappings

help to shield the hot inner part of the coil so theres less hum. If you experiment with close observations,

coils that have a hot lead attatched to the outer wrappings may hum slightly more than they would otherwise.

 

In the case of strats where they have one pickup with a reverse magnet, and connected with a reverse polarity

so it acts like a humbucker in the 2 & 4 positions, it may hum a little than the others when run solo.

 

Thats about it unless you get into some finer details. Its all based on some really basic science

that is really some fun stuff once you understand it all.

[DaveGrima]

Interesting read. I definitely understand it a little better now. Thanks.

So I have this guitar with a HB in the bridge and a single in the neck. I wanna change the push-pull volume pot from coil split to phase-reverse for the BRIDGE HB. How will this affect the sound in the bridge only, and bridge+neck positions? You can reverse the phase on the 2 coils of a humbucker alone right? What will adding the neck single coil pickup do to the equation? Will it be out of phase with the HB? Thanks.

[Mr.Grumpy]

... So I have this guitar with a HB in the bridge and a single in the neck. I wanna change the push-pull volume pot from coil split to phase-reverse for the BRIDGE HB. How will this affect the sound in the bridge only, and bridge+neck positions? You can reverse the phase on the 2 coils of a humbucker alone right? What will adding the neck single coil pickup do to the equation? Will it be out of phase with the HB? Thanks.

 

You can make a humbucker out-of-phase with itself, but trust me you don't want to do that. The output is extremely weak, like 1/10 the normal output, and it's useless. The normal way to is reverse phase on the entire pickup, so you only get the out-of-phase sound when both the neck and bridge pickups are on. It's a very trebly and thin sound with no bass.

 

I think you might be better off changing to a serial/parallel switching for your humbucker, series is the standard HB wiring, with parallel wiring it sounds a lot more like a single coil but the pickup still bucks hum.

[DaveGrima]

I have a guitar with a series/split/parallel switch. I wanna try the phase revers. Its already wired for coil split so it should be just a matter of moving some wires around. Jimmy Page is famous for having a phase switch on his number 1 LP and I love his tone.

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[fatusstratus]

Are any of the guitars you are going to do this to rear routed?

[DaveGrima]

Yes why?

[fatusstratus]

you can just use test leads to temp-wire her up and see if it appeals to you.

[WRGKMC]

Reverse phasing a humbucker is a waste of time because you'll have practically no output from it.

Reverse phase the single coil instead. A humbucker sounds best with a Series/Parallel option.

If it is a strong pickup, over 10K ohms it may sound OK with a split. Below 10K a split HB has a single

coil of less than 5K and can sound pathetically weak.

[DaveGrima]

^ Im gonna reverse phase the whole pickup like Mr Grumpy suggested. As far as I can tell thats the only way you can do it with the wiring diagrams Ive found anyway. Also the push/pull pot is already hooked up the the bridge HB so itll be easier for me to do. Im gonna give it a shot right now.

[DaveGrima]

Ok I couldnt find a wiring diagram for the exact same condiguration as my guitar. Its a Squier 51, HB bridge, single coil neck, 3 way rotary, 1 volume push/pull. I just followed the mod for 2 humbuckers. The bridge alone sounds really thinned out but the neck plus bridge sounds pretty much the same, maybe just a little less bass. I wanted the switch to put the neck and bridge pickups out phase with eachother. I must have wired something wrong because it just sounds like the bridge alone is out of phase with itself. The problem is that there are just no diagrams for this setup. ANy ideas?

[DaveGrima]

OK I got the middle position to work, Both pickups out of phase with the switch up. The bridge pup by itself is doing something really funky though. I think its in parallel with the switch down and phased out with switch up like before. It actually sounds really cool in paralell mode. A little lower output, brighter, bottom strings sound nasally have more punch like a single coil. I think Ill play it like this for a while. Bad news is the 2 screws holding the control plate down have stripped out the wood from taking it on and off too many times. Basswood ftw.

[DaveGrima]

Actaully the middle position sounds like {censored}. Im gonna redo it so the push pull toggles between series/parallel like Grumpy suggested. I imagine the out of phase thing sounds better on Page's Les Paul.

[DaveGrima]

Goddamnit. Now the bridge position is just {censored}ed. I cant find a diagram for a 3 way rotary switch anywhere. SOmeone help please.

[fatusstratus]

what kind of rotary switch - how many poles, etc?

 

what do you want the rotary switch to do specifically?

[DaveGrima]

I dont know if its the switch. Its just a 3 position rotary switch that comes standard on Squier 51s. I just wanted to wire a push pull volume pot for series/paralell on the bridge pickup. I followed the diagram on seymour duncans site exactly for the push pull part. The diagram was for 2 humbuckers and a tone knob tho. The color codes are the same as GFS. The bridge pickup just isnt working right. It sounds thin and trebley in both positions and lower output than the neck single.

[fatusstratus]

sounds like you have the humbucker out of phase internally.

 

take it out of the circuit test clip it off and listen to it in isolation

[DaveGrima]

I dont think the humbucker is broke. Something just isnt wired right. I just cant get a diagram for this configuration. GuitarElectronics.com will send me a custom ordered diagram but its just a total ripoff. Humbucker bridge+single neck+volume PP pot+3 way rotary switch. i just wanna wire the {censored}ing pushpull pot to get series/paralel for the HB {censored} how hard can it be.

[Mr.Grumpy]

 

what kind of rotary switch - how many poles, etc?

 

 

I belive the Squier '51 has a telecaster-style 3 positition, 2-pole blade switch. So, use a telecaster wiring diagram. This one is for a coil split, but you can redo the pickup and switch wiring to make it series/parallel.

 

http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=tele_1hum_1sing_pushpull

 

 

The bridge pickup just isnt working right. It sounds thin and trebley in both positions and lower output than the neck single.

The humbucker coils are out-of-phase with each other - reverse the wires on one of the coils. The color codes for pickup wiring aren't standardized, so you can't go by the GFS color code unless it's a GFS pickup.

[fatusstratus]

I dont think the humbucker is broke. Something just isnt wired right.

 

That not being wired right is what I'm talking about. It's likely that you have the coils of the humbucker out of phase (in other words, the humbucker is out-of-phase INTERNALLY...the coils of the pickup aren't in phase with one another...not out of phase with another pickup)

 

i just wanna wire the fucking pushpull pot to get series/paralel for the HB FUck how hard can it be.

 

sometimes harder than you think - welcome to tech work!

 

When you have a problem like this, especially since we have a suspicion about a subsystem (the humbucker) try a divide and conquer strategy. grab some test leads and hook up JUST the humbucker (without the rest of the circuitry)

[DaveGrima]

OK ill try it

[DaveGrima]

Ok first I tried to just wire the humbucker to the volume pot only with series/paralell. Same thing. It sounds like its in paralell in both positions. Then I wired it just series humbucker to volume and it worked. So the pickup is fine its just not wirking with the push pot. Maybe its broke IDK. I know I have the wires correct because Im using Seymour Duncan diagrams and they have the exact same color codes as GFS, which is the brand of the HB. so. .

[fatusstratus]

first things first

 

So let's break it down to basics

 

I'd take out even the volume control

 

 

Get out your

- meter

- test leads

- pen and paper

- instrument cable

- bench amp

 

and TURN OFF your soldering iron (one you disconnect the HB from EVERYTHING)

 

don't just blindly (well, deafly) trust wire color codes

 

1) use your meter to identify the leads off EACH coil

2) WRITE those down

3) hook up the humbucker in series just in free space (the leads shouldn't be hooked up to switches or pots or anything else, the only thing you should have is two pickup leads connected to one another one form coil A connected to one from coil B)

4) WRITE down the connections

5) CHECK the HB with your meter (are you seeing the proper DC resistance?)

6) use you TEST LEADS to hook the remaining to pickup leads straight to an output jack (with NO other connections)

7) connect the pickup (through the jack) to your bench amp

8) NOTE the sound (thin? strong?)

9) DISCONNECT from amp

10) REVIEW your notes and reverse the leads of ONE coil of the HB

11) CHECK the HB with your meter (are you seeing the proper DC resistance? - don't say it sounds silly. You can save yourself a headache to make sure the connection is actually there. 10 seconds of sanity checking)

12) WRITE down these connections

13) use your TEST LEADS to hook the remaining to pickup leads straight to an output jack (with NO other connections)

14) connect the pickup (through the jack) to your bench amp

15) NOTE the sound (thin? strong?)

16) DISCONNECT from amp

 

So is the HB working?

The INTERNAL phasing is understood (we'll still have to check it against another pickup)

 

 

this may seem overkill at first, but you are just starting out and the system already has a problem and there are assumptions being made and we're trying to help you across the internet.

So let's slow it down and get it sorted out.

To be honest, techs still do this stuff, just a lot of it becomes second nature (like checking connections with the meter) and doesn't register as an "extra step"

[DaveGrima]

Ok I think that is overkill, although I realy appreciate that youre trying to help believe me. I tested the humbucker with just the volume and it sounded fine. I really think its just a bad switch or a bad connection somewhere. Its a cheap Chinese pot and I think when I was soldering and desoldering trying to get the phase thing to work I just fried it. Wouldnt be the first time. Ill troubleshoot it some more later tonight.

I have another guitar thats just a single HB, volume, and 3 way mini switch I had setup for series/split/paralel. I played it for a long time thinking it sounded OK but now that I relistened to it I think the HB sounds f-ed up. Same thing, not enough bass or output in series mode. It a Fender Atomic HB so it should be really hot. I just disconnected the switch from that and wired the HB in series to just the volume and it still sounds weak. My tech tells me that Fender HBs are notorious for crapping out so I think im gonna just replace that one.I bought it off some guy for $20 so no big loss. I had meaning to replace it anyway with a Custom Custom.