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You are right; turning over one coil inverts the polarity of the signal it receives from the hum magnetic field magnetic. We all know this at some level because we have fooled around with two humbucker coils not attached to the base, but I forgot! I am not sure what you are saying about the magnets, though. If both coils sense the strings, then they have to do so with opposite magnetic polarity to stop the signals from canceling. If one coil is down underneath, any magnet in it has little effect on the strings, and the signal it receives is a result of the magnetization of the string caused by the magnet in the upper coil. Thus the signals in the two coils from the string tend to cancel if the coils are wired to cancel hum. This is one serious problem with stacked humbuckers, reduced signal.
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Okay - I think I'm good now. Thanks.Originally posted by Mike Sulzer View Post
Actually, I thought I was good before - and then Mark made the comment about the U-shaped magnet, and then I thought I must have misunderstood everything. But I'm pretty sure I have things straight now.
I have to admit that, when I started thinking about the stacked humbucker, my immediate reaction was that it was a very silly idea. Now, I appreciate that it might not be quite THAT silly - but it's still pretty silly. Especially when there are so many other arrangements that cancel hum that don't seem to have the stacked coil downsides. Rewinding existing stacked coils for those who want them makes sense. But I doubt I'll be going out of my way to wind my own in the future.Comment
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The hum cancellation can be much better than a regular side by side humbucker. So in a situation where a somewhat reduced signal level does not matter, they are a good choice. To me, that means whenever you are going to use a low noise solid state preamp, in the guitar if the impedance is high, and either in or out if medium. Since a good FET is much quieter than a 12AX7, the result is improved SNR, even with the partial signal cancellation.Originally posted by chad h View PostComment
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I've tried accelerator & I find it makes the CA very rough near the forbon so I let it cure on it's own .Originally posted by ReWind View Post"UP here in the Canada we shoot things we don't understand"Comment
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They do have super glue accelerators which allows them to set faster. I'm looking for a good source since StewMac only sells it in an aerosol can these days.Originally posted by big_teee View Post
Steve A.The Blue Guitar
www.blueguitar.org
Some recordings:
https://soundcloud.com/sssteeve/sets...e-blue-guitar/
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I don't really have a need for an accelerator, and don't need another thing to buy and stock.Originally posted by Steve A. View PostThey do have super glue accelerators which allows them to set faster. I'm looking for a good source since StewMac only sells it in an aerosol can these days.
Steve A.
It dries pretty fast, and with a little hot air, a lot faster.
GL,
T
PS: will an accelerator help me glue my fingers together faster?
I'm pretty good at that without the accelerator!
"If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
TerryComment
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The Patent Office (which scrubs these things very closely) accepted the claims, so they must have been satisfied that the claims were legally clear.Originally posted by Mike Sulzer View PostComment
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Originally posted by Joe Gwinn View Post
I think you were responding to this, not what you quoted:
Yes, I suppose they were. Or maybe not. Did it ever occur to you "scrubs these things very closely" is not what the Patent Office does? Maybe it is (or was) just some incompetent government agency that bumbled along.Yes, I know. The question I was primarily addressing is what is intended to be covered and what is not? I do not see how anyone, technical or not, could determine what claim five intends to cover. Can you? The question of what the device actually does, and whether it does as claimed, is separate, but still of interest to me, of course.Comment
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Magnetic Field
Maybe it was said already,
The windings do not all see the same variation in flux.
The magnetic field does not go from top to bottom (S to N) of the magnet nicely.
see attached drawing.
That is why the windings nearer to the strings produce more output.
Coil 1 to coil 2 would form a badly coupled transformer as well.
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Right you are.Originally posted by Mike Sulzer View Post
They are for the most part not technical experts. Their expertise is patent law, and what makes for a legally adequate claim. Their objective is to narrow each patent application such that it claims as little as possible.Yes, I suppose they were. Or maybe not. Did it ever occur to you "scrubs these things very closely" is not what the Patent Office does? Maybe it is (or was) just some incompetent government agency that bumbled along.Last edited by Joe Gwinn; 09-07-2014, 07:14 PM.Comment
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Yes, as you say, but it is the field starting from and returning to the vibrating string that matters. This field results from the permanent magnet field magnetizing the string. So once you account for this string magnetization, you can draw the field centered there, not as you have drawn it. That is, you can ignore the permanent field once you have accounted for what it does.
Originally posted by spamunkulus View PostComment
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louder an quieter windings
Voltage is generated in the wires through a flux change .
This flux Change is altered cause the
magnetic circle of the setup Coil/Magnet/string changes.
Due to the stray field more flux change happens near the strings.
There are a lot of books about magnetic fields, but one is
very well written (with humour) and deals with magnetic fields + guitar pickups.
"Die Physik der e-Gitarre" by Manfred Zollner.
Might be translated in the future.
I found a drawing similar to mine on page 5-30.
A link to this book (Chapter5):
https://hps.hs-regensburg.de/~elektr.../pdfs/kap5.pdfComment
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I believe that you are discussing figure 5.4.13, as you say on page 5-30. It shows that the total field is the sum of the field of the permanent magnet and the field induced by the magnetization induced in the string by that permanent field. However, it shows it for field lines that are well away from from directly over the magnet and are essentially horizontal. These field lines have have little to do with the voltage induced in the coil. The law of magnetic induction states that it is the change in flux that matters, the flux having a direction passing through the coil aligned with the axis. So consider instead the permanent lines that come out along the axis of the magnet and induce magnetization in the string that results in field lines that pass down through the coil. The density of these lines, passing through the coil changes when the string goes up and down. This is what induces the voltage in the coil.
The relevant principle in considering the field from the string induced by the permanent magnet is linearity. There is a total field, and it is the sum of the original permanent field and the result of induced magnetization. The permanent field does not change, and so induces nothing, and it is thus possible to consider just the induced field. The magnetization induced in the string, right over the center of the magnet, must result in a field pointing down through the coil by symmetry. Surrounding lines must curve outward as the distance down from the string increases. Therefore, vertical motion of the string must result in change in density of lines through the coil, and so a voltage is induced.
Originally posted by spamunkulus View PostComment
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