Saying Hi, asking about some basics

[Gollum]

This forum is stupid addicting.

So, I'm one of those "obsessed" people. I'm probably obsessed more with cars that music gear, but that's only because I've got a much firmer grasp on how it all works. I'm a designer through and through. I'm not happy with knowing HOW to make something, but WHY to make something a particular way. I like to really know the details and remove the mysteries that seem to plague the ignorant.

So that being said, I hope to eventually make some pickups for myself, and I've got ideas for building guitars down the road, which would probably benefit from custom pickups since my ideas are so odd anyways.

I've read as many links as I could find on pickup making and I'm still left with a LOT of questions. If anyone has any answers, or links to where I might find the answers I'd greatly appreciate it.

1. What is the exact tonal difference from one gauge wire to the next, if the mass of the wire is the same? Obviously 7000 winds of 42 gauge will sound different than 7000 winds of 40 gauges, but the mass is not even comparable.

2. Why are the common depths of a pickup common? What happens when you make a pickup "deeper", or "taller"? Does a stronger magnet allow a shallower pickup design? Vice versa? I've found very little information on why certain pickup heights are used.

3. Why don't we cover the pickups with a non-magnetic metal like aluminum? It seems to me that if you covered a pickup in aluminum and grounded the cover then that would help shield the pickup from some (not all obviously) noise. Plus it looks b^@$#in'.

4. Why do I have a hard time finding info on other magnetic materials used and how the actually sounded? I'm particularly interested in experiments with rare earth magnets. Seems to me that they might have their benefits.



Well, that's a start I guess. I'm sure I'll come up with more, but that's what's been nagging me lately.

[David Schwab]

Originally Posted by Gollum

1. What is the exact tonal difference from one gauge wire to the next, if the mass of the wire is the same? Obviously 7000 winds of 42 gauge will sound different than 7000 winds of 40 gauges, but the mass is not even comparable.

The thiner wire will have more midrange emphasis. The heavier wire will have a rounder looser kind of tone. And more low end. Thinner wire also makes a smaller coil, so it tends to be brighter, and of course thiner wire will allow winding more turns on a given bobbin.

I just did a neck position bass pickup wound with 40 gauge wire. It has a hollow kind of tone with kind of scooped midrange and extended high end. The same pickup would with 42 has more mids and a tighter tone. 43 and 44 will accentuate the mids further.

2. Why are the common depths of a pickup common? What happens when you make a pickup "deeper", or "taller"? Does a stronger magnet allow a shallower pickup design? Vice versa? I've found very little information on why certain pickup heights are used.

Some of it was design considerations, like the P bass and Jazzmaster pickups coils are shallow and wide. Jazz bass and Strats are taller and narrow. We know how each of those pickups sound.

These days many pickups are clones of Fender and Gibson designs, so the same form factor is used, even if taller or squatter might work better for a particular tone.

3. Why don't we cover the pickups with a non-magnetic metal like aluminum? It seems to me that if you covered a pickup in aluminum and grounded the cover then that would help shield the pickup from some (not all obviously) noise. Plus it looks b^@$#in'.

Humbuckers often have non magnetic covers, usually from nickel silver or brass. The more conductive the metal, the more eddy currents you will have, and the more high end will be shunted. So nickel silver or stainless steel sound best, and brass dulls the tone. Aluminum would also not be the best material to use.

4. Why do I have a hard time finding info on other magnetic materials used and how the actually sounded? I'm particularly interested in experiments with rare earth magnets. Seems to me that they might have their benefits.

Just hang around here a awhile. You don't see neo magnets used much because many people just want the same tones they grew up listening to on records, so for them they want alnico magnets and vintage specs.

I use neo magnets for bass pickups. I find they have strong mids and highs like ceramic magnets, but with more low end, similar to alnico.

Generally the stronger the magnet, the brighter/harder the tone.

[Gollum]

/bows with respect

Thank you!

Ok, so one more quick question that came up. Most single coil pickups I've seen use 6 individual magnets for the pole pieces, while humbuckers use steel pole pieces that contact a bar magnet on the bottom of the pickup. Is this done for cost or something?

The main reason I ask, is that neo magnets in rod dimensions are easier to find, and the neo bar magnets I'm finding have the polarity on the wrong face.

[David Schwab]

Gibson pickups have adjustable poles, so to do that they used steel screws and a bar magnet contacting a keeper bar. You can use rod magnets in a humbucker, as long as you reverse the polarity on each coil. Just watch out, because 12 neo rod magnets might pull on the strings.

[Howlin' Mad Mac]

It's true a magnet won't stick to aluminum but it does have some rather interesting magnetic properties... especially when combined in an alloy with other metals such as nickel & cobalt (Al + Ni + Co). Also aluminum has been used in pickup manufacture like the AlumaTone series by Lace & I'm not sure but I've seen some pickups (thinking Gretsch FilterTrons or TV Jones pickups) with what look like aluminum covers.

[Gollum]

Yea, I'm looking at pretty small neos, probably less than 1/8" diameter.

I can see the headache on figuring out how to make adjustable pole pieces if the poles are magnets... I guess it's probably easier to do it the way gibson did it, and just use separate bars for each coil to ensure correct polarity.

Well, I'm sure I'll have something figured out by the time I actually make something.

[David Schwab]

Originally Posted by Howlin' Mad Mac

It's true a magnet won't stick to aluminum but it does have some rather interesting magnetic properties... especially when combined in an alloy with other metals such as nickel & cobalt (Al + Ni + Co). Also aluminum has been used in pickup manufacture like the AlumaTone series by Lace & I'm not sure but I've seen some pickups (thinking Gretsch FilterTrons or TV Jones pickups) with what look like aluminum covers.

Everything has some magnetic properties.

The problem with a conductive non magnetic metal such as aluminum or brass is that in the presence of a changing magnetic field, small swirling electric currents form on the surface called eddy currents.

These currents then form their own magnetic field which opposes the field that created them. In a pickup, this tends to dull the high frequencies.

You can hear this with humbuckers that have covers. it can be a cool tone, if that's what you are looking for. And different metals effect the tone to different degrees. Brass or aluminum would take a lot more highs off the sound than nickel silver.

FilterTrons have nickel silver covers, and they have slots cut in the cover to suppress eddy currents. I don't think anyone uses aluminum for covers. Neil Young's Old Black guitar has a hand made aluminum cover over the neck P-90.

In the Lace Alumitones, the aluminum frame is the pickup coil. You can use aluminum coil wire if you really want to. That's different from an aluminum cover.

[Gollum]

Interesting stuff guys. Thanks for the input.

Covers aren't a huge concern of mine anyways, just a source of curiosity. I'm much more about form following function, which you'd understand if you ever saw my car.

So, it does seem that neo pickups are talked about quite a bit, and I'm really tempted to jump into it. But always I've got more questions.

Question of the day. So what's the deal with blade style pole pieces? I'm sure they offer a nice even field allowing for very little articulation loss when bending strings, but what are the true pro's and con's? It's obvious that you can't adjust individual pole heights, but I guess if you wanted to you could also vary the location of individual magnets beneath the blade pole to compensate for stronger/weaker strings, yes?

[LtKojak]

Originally Posted by Gollum

So what's the deal with blade style pole pieces? I'm sure they offer a nice even field allowing for very little articulation loss when bending strings, but what are the true pro's and con's? It's obvious that you can't adjust individual pole heights, but I guess if you wanted to you could also vary the location of individual magnets beneath the blade pole to compensate for stronger/weaker strings, yes?

No, the blade acts like a diffusor of the magnetic field, so it spreads the magnetic flux through the blade's geometry. To compensate for weaker string volume is to concentrate part of that magnetic flux under a narrow space just beneath the said string/s. It can be done adding a row of polepiece screws or altering the blade' s geometry, meaning decreasing the distance just beneath the stronger sounding strings, implying to file or cut a part of the blade.

I've been using EMG SA p'ups for a long time which are a blade design, and I've never had any problem with strings sounding louder than others to a degree that it was noticeable. Not in the studio, even less so live.

HTH,

[David Schwab]

Originally Posted by LtKojak

I've been using EMG SA p'ups for a long time which are a blade design, and I've never had any problem with strings sounding louder than others to a degree that it was noticeable. Not in the studio, even less so live.

I agree. I have never felt the need to adjust the pole under a string. Ever. On my blade pickups, as well as EMGs and Bill Lawrence pickups I have, every string is nicely balanced.

And even with poles, look at Fender pickups. You can't adjust those at all. And to me, the staggered versions sound very unbalanced from string to string.

I think all that adjustable pole stuff came from a time when strings were very different.

Now I realize that raising all the poles and lowering the pickup changes the tone, but I never liked that tone either.

[PatrickMahoney]

Hi Gang...

I know this is kind of an older thread, but I have been completely blown away
by the openness and the information you all seem so willing to share with the
rest of us in this forum.

I have just had about 4 months worth of questions answered in this one
thread, and I must say thank you all for your time and effort!

The thing that keeps amazing me more than anything about designing
guitar/bass pickups, is the seemingly endless possibilities of what can be
done. Also, I fear that I will never have a long enough lifetime to explore
them all.

I had a question I wanted to ask, and it seems that after reading all of the
information in this thread, my question has escaped me now. Go figure, I
guess that comes with age or so my parents tell me.

-----------------------------------------------
@ David Schwab:

David, I was checking out a few of the demos you have on your website the
other day, and I am totally amazed with the sounds you are pulling in on
the audios on the following web page:

SGD Pickups

...in the audio at the bottom, are you using one of your pickups in that audio
or are there several different designs being demoed there? I see the
numbered list at the bottom, but it doesn't seem to match up or I'm simply
getting it wrong. From the part of the audio where you or someone starts
playing the riff from the Tool tune "Schism", I really like that tone.

Question:

Which pickup or pickups is/are those being used in that section of music?

I'm very interested in purchasing a set.

I recently purchased an older Ibanez SDGR SR1200 bass which comes with
active electronics/pickups, but it's still lacking as far as I'm concerned. I'm
looking to get that kind-of piano-ish sound from my bass, and was wondering
if you make a set of pickups that would work in this bass?
-----------------------------------------------

@ All Forum Members:

Oh yea, I just remembered my question I have for you guys...

Okay, I've ordered a couple of 2 inch Diameter x 0.5 inch thick Neodymium
Iron Boron NdFeB disc magnets (Rare Earth) grade N50 for magnetizing my
AlNiCo 3,4 & 5 magnets for my guitar pickups.

I will be making a jig to hold these magnets 1" apart from each other. I will
also have a jig which will allow me to slide the AlNiCo magnets in-between
the rare earth magnets without the possibility of it sliding across one of
the magnet faces. See my images below of my proposed jig and tell me if
I'm heading in the right direction please or if I need to come up something
else:

======================================================== ========================
Version 1 Front View:



Version 1 Top Down View:



======================================================== ========================
======================================================== ========================
Version 2 Front View:



Version 2 Top Down View:


======================================================== ========================

Could one of you folks tell me which would be the proper way to run my
AlNiCo magnets in-between my rare earth magnets, version 1 or version 2
from above?

Also, does it look like I have the north/south setup properly on my rare earth
magnets in the jig?

I really appreciate any and all help you guys can offer me, and as I said
before, this is one of the best forums for guitar electronics I've ever found
on the web.

Thank you to all,
Patrick

[David King]

Patrick,
Some hints;
You want the bar magnetized across the width i.e. the 1/2" dimension. Not through the thickness (1/8" dim) or the length (2.25" dim.)
Set your neos just a hair over 1/2" gap.
Instead of using all the MDF you really want to be using low carbon steel to create a horse shoe circuit. The easiest way to achieve this is to buy a cheap 3" bench vise and epoxy the magnets to the insides of the jaws. You can then open the jaws the the correct distance.
Keep pulling the magnet through the gap alternating in both directions several times.
Get the biggest neos you can afford: 1 x 1 x 2" is a good size but watch your fingers. They'll come stuck together with a plastic shim in between them. Clean the outsides with acetone and epoxy them as they come to your vise jaws. When the epoxy has set, open the jaws to separate them.

[PatrickMahoney]

Hi David,

So, my version 2 (last 2 diagrams) are correct in the way I have my AlNiCo
running in-between the rare earth magnets then? I believe that's what you're
telling me.

Okay, a vice is very easy, as I have about 6 or 7 of them out in the shop I
can use for something....

Please have a look at the following diagram just to verify that I am
understanding you correctly here:

Using Typical Steel Shop Vice:



Also, should I create some kind of a jig to hold the AlNiCo bar @ center
between the neo mags as not to stick or scratch along side of them? I
thought I remembered reading somewhere that, that can cause the AlNiCo's
to not charge fully or something of that nature or am I mistaken in that way
of thinking?

Thanks, I appreciate your help and assistance,
Patrick

[David King]

Patrick,
that last diagram looks good. I don't really know about the necessity of an airgap between the magnets. It's not something I've bothered with but someone here undoubtedly knows the answer. I believe that with an impulse magnetizer the jaws touch the magnet.

Rather than sliding the alnico bars through you could just close and open the vise jaws on them a few times. It certainly helps if you have a Gauss meter to see what you've actually accomplished and how even a field you've managed to create.

[Busterdawg]

Originally Posted by David King

Instead of using all the MDF you really want to be using low carbon steel to create a horse shoe circuit. The easiest way to achieve this is to buy a cheap 3" bench vise and epoxy the magnets to the insides of the jaws. You can then open the jaws the the correct distance.

I'm curious as to why creating a horse shoe circuit with a steel jig is preferred as opposed to creating a jig using a magnetically inert material such as wood. I know I have seen an example of a wood jig used by one of the members of this forum sometime back. Is it an efficiency thing?

[PatrickMahoney]

Okay thanks David, that makes things a bit easier for me.

Just to clarify something, I should have stated a "cast iron"
vice, as a solid steel vice would be pretty expensive, if they
are even produced. he he They probably make them for some
special reason, but that's beyond the scope of this threads
purpose.

I will make a note to grab a good Gauss meter to keep an eye
on how things are working out and to try to keep things
consistent.

As far as the wood jig over the "cast iron" vise, it surely makes
things much easier, as now I do not have to spend all of that
time manufacturing something from scratch.

Thanks again,
Patrick

[David Schwab]

Originally Posted by Busterdawg

I'm curious as to why creating a horse shoe circuit with a steel jig is preferred as opposed to creating a jig using a magnetically inert material such as wood. I know I have seen an example of a wood jig used by one of the members of this forum sometime back. Is it an efficiency thing?

It completes the magnetic circuit and makes it more efficient.

It can be as simple as this. I don't normally charge alnico magnets, but this old Mustang pickup was pretty dead from sitting in a box full of ceramic magnet pickups!

[Busterdawg]

Originally Posted by David Schwab

It completes the magnetic circuit and makes it more efficient.

Ok, that makes sense to me, I had figured it was something along those lines.

I do have a follow up question to further my understanding (because, as Gollum said, "This forum is stupid addicting" and it has been one of my top "must read" web stops for sometime now).

As far as efficiency goes when using the steel jig as opposed to the wooden jig, linked to below, are we talking about efficiency as in it's quicker to magnetize the pickup or it does a more thorough job of magnetization?

'Bucker Magnet Neo Charging Jigs?

I originally thought that chevalij's wooden slide through jig was an ingenious way to control the pups time in the neo's field without banging the alnicos into the neos while trying to crank the vise open.

[David Schwab]

Originally Posted by Busterdawg

I originally thought that chevalij's wooden slide through jig was an ingenious way to control the pups time in the neo's field without banging the alnicos into the neos while trying to crank the vise open.

I just opened the vice wide enough to let it slide through. I wasn't trying to not touch the neos. The alnicos touched them on both sides.

It's the moving through the field that does the magnetizing. What David K suggested would probably work as well (opening the jaws). I haven't tried that though.

[David King]

A neo charging rig has a really hard time getting the higher alnicos up near saturation. Banging into the neos is probably exactly what you want but you need to control it somewhat or your charge centerline will be way off center.
This is easy to see with magnetic viewing paper. Better than with the Gauss meter. Of course we need to determine if an asymmetric charge is even a problem in a pickup but I like to be anal as a rule.

[Jedd]

When magnetizing Alnicos, has anyone noticed how gauss strength affects tone? I have noticed a significant output difference and it seems that stronger magnets are brighter and capture more highs, but was curious to hear others experiences on this.

[David King]

Jedd,
There is plenty of evidence that saturated magnets DO NOT sound as good as slightly demagnetized ones. I think the crux of the issue is that you want to hear it both ways with your pickups and then decide what the appropriate level of magnetizing is. At that point you can figure out how to get consistent results in the demag process. We've had many discussions about how to demagnetize to a good level but without a very good ear and a Gauss meter this is a tough job.

[Jedd]

Originally Posted by David King

Jedd,
There is plenty of evidence that saturated magnets DO NOT sound as good as slightly demagnetized ones. I think the crux of the issue is that you want to hear it both ways with your pickups and then decide what the appropriate level of magnetizing is. At that point you can figure out how to get consistent results in the demag process. We've had many discussions about how to demagnetize to a good level but without a very good ear and a Gauss meter this is a tough job.

Thanks, David. I appreciate the tip! I think I saw a few meters at grainger for relatively cheap.

[David King]

Jedd,
You don't need to go to Graingers. In fact I and almost assure you they will over-charge you for something that won't be what you need.
Have you looked at any of our Gauss meter discussions recently??

[Jedd]

No sir, I haven't. I'll take a look and see if I can find them. Thanks a bunch.

[PatrickMahoney]

Hello Again Gang,

I've come across a video of a Seymour Duncan factory tour where they are
showing how they build pickups. In one section, they are showing how they
go about magnetizing their AlNiCo bar magnets and it's got me to the point
where I am once again confused.

First off, I was sure after reading the replys to my earlier posts, that I was
suppose to magnetize my AlNiCo bar magnets so the north and south poles
were facing the front and rear of the bar magnets (pickups) like in the
following image:



In the Seymour Duncan video, they're showing that the AlNiCo bar magnets
have a north and south pole facing the sides of the bar magnets like in the
image below:



Here's a clip from the video where you can see how he's holding the Gauss
meter up to the magnet, and then holds it up to a pickup to show how the
magnet is charged, and you can see that the magnets north and south poles
are facing the sides of the pickup, not the front and rear. Here's the video
clip:

You Tube

You Tube

So, am I understanding this correctly, do I need to go back and re-charge
my bar magnets so the north and south poles are pointing to the sides of the
magnets/pickups as apposed to front and rear?

Thanks again for your help and insight,
Patrick

[David King]

Patrick,
Sorry for your confusion but you figured it out. Alnico won't hold a charge the way you magnetized them the first time. This time magnetize them properly from edge to edge across the 1/2" width as shown in your second diagram and reap the rewards.