Is there a simple way to check Phasing on Buckers?

[davos]

Hey guys,

I accidentally sent out a bucker to a customer which was incorrectly phased. No biggie to fix it but it got me thinking from a QC point of view if there is a simple way to check the phasing each time. I quickly rigged up a quick and dirty test circuit with a bunch of butterfly clips running to a simple vol/tone/dpdt (for checking the coil split functions too). Its not exactly ideal and is a bit of drag to set up so I can sit tapping coils with a screwdriver...

Is there a simpler way to do this? Some magic with a meter maybe? I remember seeing in the SD tour video that they had some special machine which let them quickly test it, some kind of dummy load maybe?

Does anyone have a quick way to check each time?

I'd really appreciate any tips if there are some to share!

Thanks,

Dave

[big_teee]

I don't know of a simple machine.
Maybe you can check this with a RCL meter, I don't have one.
If we are talking about big buckers?
I use the start lead out the bottom hole.
finish, is on top.
That makes sure the start and finish are the same each time.
Wind both coils the same direction, and wire the 2 finish leads together.
The only thing left is the magnet polarity.
I always check the magnet polarity on Pickups before they go out the door.
Either with a polarity checker, or with a Compass.
The other Polarity problem is selling single pickups.
I try to sell Sets, that way I know the pickups in the set are in phase.
T

[davos]

Yeh, Im talking about plain old regular buckers.

I had what I thought was a foolproof method of making sure everything was wound and colour coded correctly but somehow I failed on a coil (first time out of a few hundred is ok but not great) which made me aware that I hadn't been checking the phasing. I always check polarity. I think I somehow had the bobbin mounted upside down to normal on my winder causing the direction of current to be reversed, no idea how I didn't notice it.

For peace of mind and QC, I'd love a simple test to make sure another doesn't slip by me

Dave

[big_teee]

Yeh, Im talking about plain old regular buckers.

I had what I thought was a foolproof method of making sure everything was wound and colour coded correctly but somehow I failed on a coil (first time out of a few hundred is ok but not great) which made me aware that I hadn't been checking the phasing. I always check polarity. I think I somehow had the bobbin mounted upside down to normal on my winder causing the direction of current to be reversed, no idea how I didn't notice it.

For peace of mind and QC, I'd love a simple test to make sure another doesn't slip by me

Dave

I did that one time on a mini bucker.
The bobbin looks nearly the same either way you flip it.
I had one mounted up side down.
It was a rewind and the metal cover was on it and in the guitar, before we noticed it.
So I know what you mean.
If you come up with something simple, let us know.
T

[SonnyW]

Yeh, Im talking about plain old regular buckers.

I had what I thought was a foolproof method of making sure everything was wound and colour coded correctly but somehow I failed on a coil (first time out of a few hundred is ok but not great) which made me aware that I hadn't been checking the phasing. I always check polarity. I think I somehow had the bobbin mounted upside down to normal on my winder causing the direction of current to be reversed, no idea how I didn't notice it.

For peace of mind and QC, I'd love a simple test to make sure another doesn't slip by me

Dave

Here is one simple way to check phase on humbuckers, using a needle type ohmmeter and a screwdriver - it is in this thread:

http://music-electronics-forum.com/t17829/

[davos]

Thankyou Sonny! That's exactly the kind of thing I was looking for, Off to Maplin!

[Joe Gwinn]

Simplest way is to put a piece of mild steel on the poles of one coil of the pair, connect a voltmeter to the coil, and pull the piece of steel off the pole quickly while watching the voltmeter. Which polarity does it indicate? For the music to not cancel, both coils should give the same polarity.

[SonnyW]

Simplest way is to put a piece of mild steel on the poles of one coil of the pair, connect a voltmeter to the coil, and pull the piece of steel off the pole quickly while watching the voltmeter. Which polarity does it indicate? For the music to not cancel, both coils should give the same polarity.

Hello Joe,

I hadn't thought about using the voltage to check phase, I have been doing it with the ohm meter. So I thought I would give this a try, it is the same principle, and actually more direct. It works well. This method will work with a DVM, which most people are going to have. So I thought I would expand on this a bit and contrast the two methods.

Davos,

The post I listed before originally by Possum uses the ohms reading scale. The post by Joe Gwinn uses a voltmeter, either one will get the job done.

With the ohmmeter, the reason to use the needle type is because you usually have a zero adjust and you can get the needle into the middle of the scale. That way it is easier to see which way it moves. This is the method I use because I hadn't thought of doing it like Joe suggested. I have an old Simpson 260 that is great for this. It was my high school graduation present in 1966. I leave it set up on my bench just for this test.

With a digital voltmeter, set the scale on DC volts and a millivolt scale if the meter isn't autoranging. Put your piece of steel (I used a screwdriver) flat on the poles and hold it still for a second until the reading goes to zero. Then pull it off quickly and note the sign of the voltage generated. Do the same with the other poles. They should be the same sign.

With either method you can check that you are getting a proper reading by reversing the leads. The sign or the needle direction should be reversed when you do this.

[davos]

You guys are awesome! Thankyou so much for going into detail for me.

I have a DVM, Ill keep an eye out for a needle meter too - Lots of weekend markets with older electrical things near me.

I just found this video on youtube too that shows what you guys were describing pretty well using both types of meters (probably from someone on the forum) Identifying Pickup Wires & Polarities - Humbucker - YouTube.

It seems that the jumps the meters show when you place steel on the poles is the same as when you tap poles of an amplified pickup and hear that sorta knock sound. Science is neat.

Thanks again guys!
Dave