Gaussmeter Kit Group-Buy

[David Schwab]

David, any news about your second probe?

Not yet. I had a couple of sets of pickups to finish, but I'm going to get to it in the next couple of days.

I also misplaced my other microphone plug, so I have to find that.

[StarryNight]

Well just for comparison an alnico D or G pole fully charged is about 1200 guass, not fully, around 1000-1200. I use the AlphaLab gaussmeter...

I'm getting around half that reading for A5 which may be the result of my creative wiring hookup to the Hall sensor . In all other respects my meter works great and gives relative readings correctly. Im probably going to order another sensor at some point. I'm finding the meter very useful for degaussing relative to the highest reading. I'm going to have fun expirementing with hearing the effects of degaussing at different readings!

[RedHouse]

I'll try to touch on all this in one post because I don't have a bunch of free time today, so here goes...

...In another thread one of these guassmeters is reading 438 guass off a D or G pole, that is really exceptionally low reading. Is it alnico 3? I have some alnico 3 strat pickups here and they read about 650 guass. What are you calibrating these meters against?...

...Well just for comparison an alnico D or G pole fully charged is about 1200 guass, not fully, around 1000-1200. I use the AlphaLab gaussmeter...

same values for me...

ciao

I get about the same on a fully charged A5 like 1000/G to 1200/G but that would only be the tall two in a staggered set and I don't usually use them fully charged so 1200/G isn't a reading I would expect to see.

This is the other thread Dave is referring to BTW.

That will only show you the gauss reading where the probe is. You need to measure the gauss over the whole face of the magnet.

With this meter (Elepro's) in "Nm" mode this would be true but as has been said before in these threads you should use the meter in "Ph" peak-hold mode for measuring pickup magnets.

pickup you see is alnico II , I used neodymium make change gauss level

I do this correctly or not?

The A1302 won't do Neo, you need the AD22151, please read the thread.

Just a heads-up realtonecustompickup has told me in PM's that he "hasn't read the threads" siteing language-barrier issues. I suggested he find a friend who can read the threads and translate for him because it's very important to understand the hookup, warnings and operations described fully in the original project thread, or the PDF, all the info is already here and there.

...is that thing accurate?....What are you calibrating these meters against?...I use the AlphaLab gaussmeter...

Speaking of reading these threads for the last 3 months, 15 pages, and 512 posts, most have noticed by now what we're calibrating these against, but, one more time for the thread-challenged among us....
(the thread is quite long)

The professional gauss meters that JasonL (AlphaLab) and WolfM (Bell 1200) both so kindly offerred to help out with are what we calibrated against.

Both read gauss in what our meter calls "Nm" or normal mode so they have the same wildly fluctuating readouts as you move the probe around a magnet. The "Ph" mode in our meter is one of the coolest things that set this meter apart from many others in the low price range.

We had 3 "control" specimens (magnets) a vintage A5 rod from a Strat coil, a new A5 bar which Wolfe provided and charged with his charger (didn't ask his source) and a ceramic bar I supplied from a MIM Strat pickup.

Both Jason and Wolfe measured all three of the magnets and we wrote down our "best observations" of their readings. Initially our Elepro meter was reading high when set to the Allegro A1302 data sheets calibration of exactly 1.30mV/G.

With Elepro's nice calibration feature the meter was able to be adjusted so it's actual reading agreed with the meters of Jason and Wolfe and the three control specimens.

Then one night I sat down and one-at-a-time plugged each A1302 sensor into this test rig and this test probe which also went to visit both Jason and Wolfe, and I was able to find a calibration value so everyone's A1302 sensors would get readings within 0-50/G of the pro meters.

capish?

One last note on those AlphaLab meters, they use a sample-and-hold technique that samples like 3-5hz so if you move your probe around you will be missing a lot of readings. Elepro's software/firmware takes way more samples (1024 in "Nm") and acts much more like Wolfe's meter which was very fast and sensitive. Elepro's meter in "Ph" mode has the best of both worlds, fast sampling, peak value hold...very cool.

...Any forum member who owns a decent commercial digital gaussmeter, who would agree to take part in this group effort, please PM me.

Funny (but nice) you're chimming-in now about the gauss meter accuracy thing Possum, I mean it would have been nice (and helpful) if you'd have chimmed-in when this all started back in July, just guessing here but does reading magnets fall into the category of coveted hard-earned secrets?

BTW you were not alone, absolutely none of those here who have publicly posted they own professional gauss meters, and have been advising others here to get one, offered to help with this. It was only when I personally contacted Jason and Wolfe outside of this forum through their email addresses that we got offers to help us out. All of us who participated in this group project thank them both very much for kindly responding ...and agreeing to help us.

A couple of stand-up guys!

[David King]

Originally Posted by realtonecustompickup View Post
pickup you see is alnico II , I used neodymium make change gauss level

I do this correctly or not?

I think realtonecustom is asking about how to effectively gauss/ degauss an alnico II magnet. I believe that many people here have used neodymiums for this purpose with excellent results. I haven't spent a lot of time playing with this but I think Alnico II is very sensitive so a smaller neo might be more controllable.

Possum has a gauss meter already so I can understand why he wouldn't be following this thread too closely. I can also appreciate that he might be concerned if a whole bunch of us were spouting gauss figures that didn't relate to his figures.

[RedHouse]

I think realtonecustom is asking about how to effectively gauss/ degauss an alnico II magnet. I believe that many people here have used neodymiums for this purpose with excellent results. I haven't spent a lot of time playing with this but I think Alnico II is very sensitive so a smaller neo might be more controllable.

Possum has a gauss meter already so I can understand why he wouldn't be following this thread too closely. I can also appreciate that he might be concerned if a whole bunch of us were spouting gauss figures that didn't relate to his figures.

Yes you are probably right on both. I won't spout any figures that conflict with his.

[Possum]

....

Yeah I didn't read it at all because I have the AlphaLab meter, maybe it doesnt' sample as fast as the DIY version buts its not something you even notice, there is no lag in readings thats even perceptible. I built the cheapie Radio Shack gaussmeter a long time ago, it only did relative readings and couldn't handle very strong magnets. I don't have time to build something like these guassmeters, they definitely are very cool.

If someone built them for sale i'd be interested in one. Too busy making pickups full time, the bulk of my "free" time if there is such a thing is devoted to pickup experimentation stuff. The only thing I don't like about the AlphaLab is the cord is long and tangles and twists easily. I had one probe die for no reason and it was $80 to replace it, that was no fun. Other than that the probe is tiny and will go into real small tight places which is an advantage for experimental work, it has a very high range of readings and is easy to use. Someone was making inexpensive clones of them on Ebay awhile back, I kick myself for not having bought one as a backup.....

[RedHouse]

...The only thing I don't like about the AlphaLab is the cord is long and tangles and twists easily.....

Wolfe mentioned the same thing about his Bell, he said "don't make your probe like this" refering to the long and easily twisted cord.

[realtonecustompickup]

I understand then Ph mode , thank you very much
other problems I'm looking a friend for help
I'm sorry, everyone , If I understand the difficulty.
I hope that will not create a nuisance to everyone.


see you

thank you very much

[Possum]

....

A couple of things to know about using a gaussmeter. The tallest magnet on a strat is going to have the strongest charge. The end magnets will act as the end of a large magnet and thus have a higher charge there, they work in unison, not just seperate poles. If you read the edge of a magnet face thats where the strong charge is as well. South side usually reads stronger than north.

[RedHouse]

...If you read the edge of a magnet face thats where the strong charge is as well. South side usually reads stronger than north.

Amen to that.

I'd like to add that on bar magnets (humbucker) don't be surprised to see it's reading vary as you move the probe along it's long edge.

The sensor's active area is very small, like the point of a pin so you have to move it around to find the max gauss reading, that is why the "Ph" mode is so useful without it you have to look at the display and try to remember the highest reading you saw as you moved the probe around.

Here is a diagram of the way I see the sensor working on pickup magnets:



Also it seems that having your finger (or anything else but the probe) near the probe tip can effect the reading, and moving the probe tip around rapidly can effect the reading giving a false high.

I'm going to add this pic to the PDF.

[realtonecustompickup]

About Charging the magnet from Neo, Do i have to Charge to its Full renge?

If i set value from the capacity of Neo to be close to the old pick up,like a vinntage one. Is there any davantage or disadvantage.

I usually use neo 3.5 cm x 2.5 Is it too Big? What about you guy, Do you use anything beside neo?

by the way thank you in advance.

[David King]

Neos do a good job charging alnicos to their maximum capacity if you have a proper charging circuit like a steel or iron vise so that you are touching both ends of the alnico at once. Without the circuit you are likely to get an uneven charge where part/s of the alnico aren't doing anything or the neutral point is way off-center. I can't tell you if any of this really matters that much.
If you want to achieve a reliable partial charge then I think you will need a much smaller neo. i don't really know how to get there other than demagnetizing by tapping the alnico with the neo a few times until I get a satisfactory reading.

I would start a new thread so that more folks who know about this question will see it.

[LtKojak]

Neos do a good job charging alnicos to their maximum capacity if you have a proper charging circuit like a steel or iron vise so that you are touching both ends of the alnico at once.

So, you need to actually TOUCH the AlNiCo with both Neos to charge it?

I didn't know that.

[Possum]

....

You need a pretty large neo to charge alnico fully. I have a neo bar thats about 2.5" long x 1/4" thick and 3/4" wide and it won't fully charge alnico 5 compared to my charger. Before I got the charger I got a large neo block, the thing is scary as hell its so strong, I bought two of them and they came stuck together seperated by a piece of wood, I never had the guts to pull the wood out knowing the two would slam together. They explode if that happens.

I'm not so sure using peak hold on your guassmeter when measuring a bucker magnet is such a great idea. If your probe wanders along the edge of the pole side it'll read higher than whats coming off the face. I think its better to slide it along and watch the numbers in real time.

[RedHouse]

...I'm not so sure using peak hold on your guassmeter when measuring a bucker magnet is such a great idea. If your probe wanders along the edge of the pole side it'll read higher than whats coming off the face. I think its better to slide it along and watch the numbers in real time.

I most definately disagree with that.

I know your AlphaLab doesn't have this feature and so that's what you are used to doing but this peak-hold feature is way better than doing it that way. You should try it before you think otherwise.

Slide the probe along slowly just as you would with your AlphaLab meter. All magnets are observable reading higher at their edge than the face, it just is-what-it-is any device you read the magnet with. Look at the pic posted above. This meter just holds the highest reading it encounters until the probe is removed from the magnetic field.

Peak-hold eliminates some opportunities for error in other meters (both user and device) for instance:

• you may blink right when it reads a highest reading, or forget what it was if distracted
• you may look away from the display to make sure you have the probe correctly on the magnet and miss a higher reading than you remember
• the probe may hit a high spot in-between samples the meter takes
• the probe may hit a high spot in-between when the data was flushed to the LCD screen.

The peak-hold mode just remembers the highest reading for you at 64 samples per display update which appears to my naked eye to be around 4-6Hz (1024 samples in "Nm" mode). Much more samples and much faster than many other units.