what are normal gauss readings

[Mike Sulzer]

To have something repeatable, I put together a Stew mac humbucker kit. The measurements are, 3/32" from the slug or screw, in Gauss:

slug side:
-118.63412 -120.98911 -129.23170 -136.29675 -130.99792 -117.16220

screw side:
105.68147 103.03206 104.50398 106.27026 103.03206 113.04093

3/32" from the edge of the magnet alone is about 250 Gauss.

This is an A1322LUA, Device 10, factory calibrated. I use a coefficient of 3.39 mV/G. This is derived by interpolating the three supplied values for three different power supply voltages to get a value for my measured voltage.

[Mike Sulzer]

I magnetized and measured some 5/8" long stew mac strat type magnets, same setup, 3/32" away. Average value is about 410 gauss.

[peskywinnets]

To have something repeatable, I put together a Stew mac humbucker kit. The measurements are, 3/32" from the slug or screw, in Gauss:

slug side:
-118.63412 -120.98911 -129.23170 -136.29675 -130.99792 -117.16220

screw side:
105.68147 103.03206 104.50398 106.27026 103.03206 113.04093

3/32" from the edge of the magnet alone is about 250 Gauss.

This is an A1322LUA, Device 10, factory calibrated. I use a coefficient of 3.39 mV/G. This is derived by interpolating the three supplied values for three different power supply voltages to get a value for my measured voltage.

Thanks Mike, I'm getting pretty much the same readings...

Baseline DVM reading 2.478V
DVM Reading above slug 2.321V (at string height)
DIFFERENCE -0.157V
GAUSS (1.3mv per gauss) 120.77 (north)



(I don't normally have a red lead going into the DVM common socket, but I needed a third hand, so pressed the only test lead I had with a croc clip on the end into service!)

that'll do me - cheapest gaussmeter ever - $2.00 for the Allegro sensor, a 78l05 regulator & a strip of scrap veroboard!

[David Schwab]

Why?

Because if you move a slight distance farther or nearer you will get a large change in readings. To say "where the string is" assumes strings are always the same distance above the pickup. And what do you do when the pickup is not in a guitar? If you read it from the pole piece you will have a more standard reading from pickup to pickup.

Here's some readings on pickups that are sitting on my desk:

From a plastic bobbin alnico 5 strat pickup; Low to high:

745, 740, 637, 730, 647, 693, all North up.

A Duncan Jazz neck pickup reads about 280 (South) on the slug side, and 250 (North) on the screws.

A DiMarzio Al De Meola bridge pickup (alnico) reads 160G. A DiMarzio SDHB reads 420 on the South set of poles and 360 on the North set.

[Mike Sulzer]

Because if you move a slight distance farther or nearer you will get a large change in readings. To say "where the string is" assumes strings are always the same distance above the pickup. And what do you do when the pickup is not in a guitar? If you read it from the pole piece you will have a more standard reading from pickup to pickup.

Large change: But you don't. You fasten a spacer to the sensor so that you are always the same distance away, just as accurately as if you were measuring with the sensor against the pole face. The repeatability of most of the measurements on the humbucker screw side (a fewposts ago ) shows that the measurements are not variable as you might think. Can you guess why the ones on the slug side are more variable?

Where the string is: There is nothing wrong with assuming a typical distance and using that as a reference. It is a hell of a lot better than measuring where the string never is.

Not in a guitar: Is this a Zen question? Does it relate to the sound a falling tree makes when no one is there? Well, it certainly has nothing to do with the sound of one hand clapping. I prefer to be more practical; it does not make any real difference whether the pickup is in a guitar or not. Measure at the same distance.

[peskywinnets]

I tend to agree, that - for a pickup maker - it's got to be more informative taking a gauss reading where the string is.

It's akin to a sound engineer....he doesn't put his ear up against the PA to get the levels right, he sits where the listener sits - that where the sound level needs to be measured & has to be right. He might hold an interest in how much power the PA can kick out, but at the end of the day, it's the sound level as presented at the listeners' ears that counts.

[Peter Naglitsch]

How come we always get into the "there is only one way to bake a cake" mode?

My take on this is: If you are aiming to produce pickups in a repeatable way consistency is your friend. Measuring with the sensor butting up against the magnet makes a very repeatable way of doing things. Of cause you can make a simple plastic distance gauge and measure magnets in situ in the pickup, but most of us magnetize the bar, test its Gauss level and then assemble the pickup. So it is highly impractical to realize the magnets hasn't been fully charged (or not degaussed to the correct level or whatever...) when you have completed the pickup. Thats why I always measure the Gauss with the sensor directly at the magnet top. But thats just me...

[big_teee]

How come we always get into the "there is only one way to bake a cake" mode?

My take on this is: If you are aiming to produce pickups in a repeatable way consistency is your friend. Measuring with the sensor butting up against the magnet makes a very repeatable way of doing things. Of cause you can make a simple plastic distance gauge and measure magnets in situ in the pickup, but most of us magnetize the bar, test its Gauss level and then assemble the pickup. So it is highly impractical to realize the magnets hasn't been fully charged (or not degaussed to the correct level or whatever...) when you have completed the pickup. Thats why I always measure the Gauss with the sensor directly at the magnet top. But thats just me...

I totally agree!
And the out of the guitar Question and answer, is if you are making and selling pickups, not guitars, you want to check the magnet when you charge it.
I'm going to do that with the magnet in my hand, not in air at different distances.
Also if you are checking above the strings, you have so many variables.
If its a strong ceramic, it will be far different than a mildly charged A3, or A2.
Peace,
Rock on!
Terry

[Mike Sulzer]

How come we always get into the "there is only one way to bake a cake" mode?

I agree that one should not do that. Different measurements are needed for different things. That is why I measured both the magnet alone, and then above the pole pieces (for the measurements a few posts ago).

[David Schwab]

Large change: But you don't. You fasten a spacer to the sensor so that you are always the same distance away, just as accurately as if you were measuring with the sensor against the pole face. The repeatability of most of the measurements on the humbucker screw side (a fewposts ago ) shows that the measurements are not variable as you might think. Can you guess why the ones on the slug side are more variable?

Where the string is: There is nothing wrong with assuming a typical distance and using that as a reference. It is a hell of a lot better than measuring where the string never is.

Not in a guitar: Is this a Zen question? Does it relate to the sound a falling tree makes when no one is there? Well, it certainly has nothing to do with the sound of one hand clapping. I prefer to be more practical; it does not make any real difference whether the pickup is in a guitar or not. Measure at the same distance.

Yes, that's all true, and we can also just measure it at the poles. It might be useful to know how much the magnet strength is at the string, but what would be the advantage of that measurement? To measure string pull?

Then if you want to use a spacer it would be helpful for that to be standardized. That way if someone here for instance is posting notes about a pickup, it has meaning to you. It's not an arbitrary variable. It would be like a listing of sound pressure levels, where it's rated as x at x inches. But if you measure right at the pole, you know where to take the measurement. That was my point.

Otherwise it makes no difference how you do it.

[David Schwab]

How come we always get into the "there is only one way to bake a cake" mode?

My take on this is: If you are aiming to produce pickups in a repeatable way consistency is your friend. Measuring with the sensor butting up against the magnet makes a very repeatable way of doing things. Of cause you can make a simple plastic distance gauge and measure magnets in situ in the pickup, but most of us magnetize the bar, test its Gauss level and then assemble the pickup. So it is highly impractical to realize the magnets hasn't been fully charged (or not degaussed to the correct level or whatever...) when you have completed the pickup. Thats why I always measure the Gauss with the sensor directly at the magnet top. But thats just me...

Yes, that was my point. You can bake a cake different ways, but if you are inventing your own measuring cups your recipe wont be of use to someone else who is using a different measuring cup. Standards are a good thing.

[Mike Sulzer]

It might be useful to know how much the magnet strength is at the string, but what would be the advantage of that measurement? To measure string pull?

The magnetic field where the string is what magnetizes the string.

[David Schwab]

The magnetic field where the string is what magnetizes the string.

And again we have to make assumptions as to where the string should be. I think that's fine if the measurement is listed at ".5" above the pickup", etc. It is kind of like saying this is a 50 watt amp, but how loud is it at 50 feet? It's still a 50 watt amp, and the magnet strength at the pole doesn't care about how far the string is.

We also take measurements of magnets before they are in the pickup even though what you read at the pole is different. All good info to have.

[Mike Sulzer]

And again we have to make assumptions as to where the string should be.

So what? 3/32" is a much better representative of where the string is than at the pole piece.

If all pole piece types have the same relative decrease of field with distance, then the issue is not of much importance. A constant factor can be used to get form the surface to where the string is.

But I do not think that this is true. Why would the field of a blade fall off at the same rate as a humbucker slug? The geometry is very different.

[RedHouse]

The magnetic field where the string is what magnetizes the string.

Mike you're over thinking things AGAIN, we (pickup makers) don't want to know what the gauss is at the string.

We want to know what the gauss is at the pole as David said earlier because we want to charge other magnets with a same/similar value and getting closest to the pole just off axis and doing readings works the best.

Your spacer isn't necessary as the sensor is encapulated and it's face has it's own spacer built-in, so again as pickup makers we don't care what the gauss is at 3/32 or 1/8" or whatever because when we build a pickup we don't have any control over the end-user's string height adjustment and we really don't care anyway as it has nothing to do with build consistancy or repeatability in the build process.

I'm not saying it's un-interesting (gauss at string height) just fairly useless to building pickups on a day-to-day basis so doesn't need much churn.

back to the OP's topic...

i just put my 3.0 gauss meter together ....thanks Elepro......
im using the A1203 sensor. i have been taking some readings of magnets & pickups i just fully charged some alnico 5 magnets ,my meter was reading 650 gauss is there a chart or something of what readings i should get ?

Hey Copperhead, do some searching on this forum from back in August->Dec 2009 when we had the first iteration of Elepro gauss meters, it seems to me shortly after a bunch of folks built theirs everyone started posting gauss values of different magnets.