Cryogenic treatment of guitars warning

[The Dude]

The "ignore user" list is a wonderful thing.

[Chuck H]

The lynch pin the any contrary argument is that there is absolutely no AC potential without the vibrating string.

A vibrating string is energy happening. It isn't potential. The electromotive force is the potential. And that is the magnet. Just as it is with a microphone. It's not your voice that powers a microphone either. And, incidentally, your mouth isn't being magnetized by such devices. Your voice makes the coil move, disrupting the steady state of the magnetic field within the coil because the magnet is fixed.

Does the circuit connected to the pickup take energy from the magnet?

Why should it? Does it take energy from the strings? Atrophy and entropy should be considered here. Do you ever gauss the strings? Energy WAS put into the magnet. And the term "permanent" is a misnomer. Think of the magnetic field within the coil as kinetic rather than static.

[Chuck H]

Ok. Look. I don't give a fat fish how the specific terminology of a given discipline can be used to skew the perception of an obvious issue. Were "I" studied in physics, and therefor able to speak the language to some satisfaction, I'm sure there would be plenty of "proper" information in my favor. It's just stodgy to hide behind nomenclature as a pretense for correctness. Like some Victorian lord with a powdered wig, no real sense and too much confidence.

There is no power in the coil. There is no power in a guitar string. There is power in a magnet. Yes there is. Even when your guitar isn't plugged in it's the magnet that is still pulling on the strings. It's AC electricity going into an amplifier from the pickup. That doesn't come from the string. Unless the string is getting it from the magnet. The energy of the string never gets to the amp. Only the energy from the magnet inducted into the coil does. I don't care how you want to slice it or word it.

[Mike Sulzer]

The issue here is not terminology, but concepts. A generator turns mechanical energy into electrical energy. A guitar pickup does the same, on a much smaller scale and much less efficiently.

By the way, learning a science is about learning concepts. The terminology just provides a convenient way of expressing them.

Ok. Look. I don't give a fat fish how the specific terminology of a given discipline can be used to skew the perception of an obvious issue. Were "I" studied in physics, and therefor able to speak the language to some satisfaction, I'm sure there would be plenty of "proper" information in my favor. It's just stodgy to hide behind nomenclature as a pretense for correctness. Like some Victorian lord with a powdered wig, no real sense and too much confidence.

There is no power in the coil. There is no power in a guitar string. There is power in a magnet. Yes there is. Even when your guitar isn't plugged in it's the magnet that is still pulling on the strings. It's AC electricity going into an amplifier from the pickup. That doesn't come from the string. Unless the string is getting it from the magnet. The energy of the string never gets to the amp. Only the energy from the magnet inducted into the coil does. I don't care how you want to slice it or word it.

[mr fab]

hello everyone
a newbie from Australia here...have been reading this forum with great interest for some time now.

i feel that what we are talking about (guitar pickups), are transducers, ie devices which convert one form of energy into another. In the case of a guitar pickup it, it converts mechanical energy from the vibrating string into electrical energy. there are various subcategories of transducers, such as actuators, sensors etc

i also wanted to add that whilst it would be worthwhile to test a whole pickup, if it were to fail being subjected to cryo treatment, then there would not be much to test afterwards. however testing polepieces of various types of steel alloys, and magnets, baseplates etc may give useful results.....

to test the effects copper, i would suggest some humbucker bobbins made up but not assembled in a pickup., and maybe a soft aircoil of sorts which would not be stressed by any mechanical damage cause by thermal contraction and enough wire to wind a number of bobbins (at least then this wire could be used to wind a bobbin, in the event the pre-wound ones fail)

after characterisation of any changes to each of these components, then a pickup could be assembled, using cryo'd parts and non cryo parts as required. substituting parts as required to hear the audible results

just my thoughts and i would be happy to donote some wound HB bobbins for testing

[Chuck H]

Well I need to concede that I agree a pickup works like a generator. Something needs to crank the turbine. But it's still the flip flop of polarity and the strength of the magnet/s that generates the voltage. Seems The Dude was right. It's a language barrier and not a misconception on anyone's part. It seems to me that a study in physics is going to provide for much more complex concepts than a pickup or a generator. In this regard, breaking it down only seems to confuse the issue for most people. In this light I'll rescind my comparison of internal combustion engines running on either explosions or gasoline and say rather that a complex explanation of how cars run on carbon would only serve to complicate the issue beyond usefulness even for the purposes of engine designers. Ergo, in layman's terms and the intention of being more clear, the voltage present at the output of a pickup is there because of the magnet as read by the coil and oscillated by the guitar string. It really didn't need to be complicated like this except that someone here started this stupid thing in an attempt to make me wrong about something for petty reasons. This did, and could only have served to confound a generally understood concept and interrupt other discussions.

[Rick Turner]

Chuck, wrong again.

There is NO flip-flop in magnetic polarity when a string vibrates above a pickup UNLESS you put a North pole and a South pole close on either side of the string in which case you'll be hearing a lot of scratching sound...it's called Barkhausen distortion, and it results from sudden changes in the polarity of magnetic domains.

If you want to hear it, then take a humbucker...plugged in, but not mounted in the guitar...hold it close above the strings and run it linearly along the axis of the strings. As the N and S poles run along the strings, the magnetic domains will flip and you'll hear it. You can also do this with an air core coil mounted under the strings (as we did with our dummy humcanceling coils at Alembic) and run a magnet along the strings with the magnetic polarity running parallel to the axis of the strings. One of the interesting things about the Barkhausen effect is that the domains don't flip all at exactly the same time, and so you hear a kind of scratching sound.

To reiterate, the magnetic field induced in the strings by the magnetic circuit of the pickup does not change polarity as the strings vibrate.

There is a massive misunderstanding of how pickups work here, to say nothing of a misunderstanding of the language of physics.

[Mike Sulzer]

..the voltage present at the output of a pickup is there because of the magnet as read by the coil and oscillated by the guitar string.

The coil does not "read" the magnet. The magnet magnetizes the string and the changing field through the coil from the vibrating magnetized string induces a voltage.
Take out the magnet, and the pickup works at a low level because the string retains some small amount magnetization. Clearly, the magnetization of the string is what counts.

If you do not like people correcting you, then stop posting nonsense. Concepts are your problem, not language.

[ScottA]

Seriously? By whom?

That was a joke.

Rick had a sense of humor earlier in the thread...

[Rick Turner]

Some curmudgeons do have a sense of humor! That and a love of clear and concise language that accurately represents reality as is generally understood. There's been a lot of non-reality spouted here, and frankly, it's annoying on a forum that purports to be about the truth about guitar and bass pickups. There has also been a fair number of posts that represent facts. I'm here just trying to add to my own factual knowledge...and sometimes have a little fun whilst doing so. That's what the proposed experiments are about.

I can tell you that this whole thread has inspired in me a lot of research into various ferrous alloys, and there are some really interesting ones out there that do not seem to be used generally in guitar pickups...this is stuff way beyond the usual 1018, 1020, etc. It's also got me thinking about ways to make the magnetic circuit of a pickup more efficient and get more of the flux modulation down into the coil(s).

[potatofarmer]

Boy, where's a metallurgist when you need one... I'm not one, sadly, but it looks like the hardening mechanism of cryogenic treatment is preciptation. What phases are present in (whatever grade) Alnico, what precipitates do you expect to form, and how will that affect the magnetic properties?

Anyone got a scanning electron microscope in their garage?

Alnico has a low temperature coefficient for the quantity Br. An irreversible loss of magnetization of about 10%
has been observed after operation at -190 0C [74], [77]. The lowest suggested operation temperature for Alnico
is -75 0C. The demagnetization curves of Alnico at different temperatures are shown in Fig. 42.

http://www.nikhef.nl/~jo/quantum/qm/prr/ET-026-09.pdf

LN2 is, what, rougly -195C? Just degauss your magnets 10% and call it even. Also I managed to find reference #77 in the collections of two local-ish public libraries. Since the idea of subjecting alnico alloys to cryogenic temperatures was already fleshed out back in 1962, yinz might want to get your library cards out.

I haven't looked at the properties of magnet wire, but since any alloying elements will reduce its conductivity (as will cold work) I have to assume it's fully annealed (and thus fully softened) or at least as much as possible to get the highest conductivity in %IACS. (percent of the International Annealed Copper Standard... weird coicidence, huh?!) - No solute-rich phases from which to generate precipitates means no precipitation.

And just to continue the overall tone of the thread: using a sample size of 1 plus 1 control does not void the null hypothesis.

[salvarsan]

Boy, where's a metallurgist when you need one... I'm not one, sadly, but it looks like the hardening mechanism of cryogenic treatment is preciptation. What phases are present in (whatever grade) Alnico, what precipitates do you expect to form, and how will that affect the magnetic properties?

I don't presume to be a metallurgist, but I don't need to be one, only scientifically literate.

Alnico separates into iron-cobalt alloy crystals in a nickel-aluminum matrix. The carbon content (usually unstated) is important and has a profound effect on the crystal size as the alloy solidifies. 1% carbon present entirely as iron carbide means 14% iron carbide in the sample. Iron and nickel carbides are historically well-elucidated. More carbon -> smaller crystals.

(NB, the carbon is rarely entirely metal carbide, existing instead as an equilibrium mixture of carbon and carbides whose proportions are determined by post-melt treatment. -drh)

The metal carbides are so thermodynamically unstable that they disproportionate under mechanical stress...(cough!), er, decompose when you beat on them. Dimensional thermal coefficients (shrinkage) of the component metals are down in the 0.1% to 0.5% range for ambient-to-cryogenic temperature cycling, so the shrinking force drives carbon precipitation from metal carbides.

Less well-known is that tiny amounts of niobium are an effective carbon getter in the magnet alloys. The NbC+Nb₂C are more stable than iron or nickel carbides and may be removed from the melt as brown sprue, however too much free niobium reduces the already low permanence of alnico.

LN2 is, what, rougly -195C?

77K for a few of us.

Just degauss your magnets 10% and call it even.

Okay, comedian. (heaves long quiet exasperated sigh)

The dockamint statement referred to the alnico magnetic field temperature coefficient and the decrease in remanence at temperature, not the remanence and permeability changes attributable to microstructural changes from cryogenic treatment.

The alnico remanence changes are not so irreversible and should be recovered by remagnetization if you really need that last 10%, at least if you find the industry's Permanent Magnet Guideline 1988 doc credible in the least.

I haven't looked at the properties of magnet wire, but since any alloying elements will reduce its conductivity (as will cold work) I have to assume it's fully annealed (and thus fully softened) or at least as much as possible to get the highest conductivity in %IACS. (percent of the International Annealed Copper Standard... weird coicidence, huh?!) - No solute-rich phases from which to generate precipitates means no precipitation.

I haven't looked at copper+cryo much either, however, precipitation is not the sole mechanism by which metal/alloy microstructure changes. Copper has mechanical creep even at 77K, to see it written. Not much info on that yet, sorry.

And just to continue the overall tone of the thread: using a sample size of 1 plus 1 control does not void the null hypothesis.

But ... but ... but ... what about sample skew and kurtosis?

Honestagawd, I'm not busting your chops Paul, but I have tried hard to put forth a scientific basis for the fact that cryogenic treatment affects pickup materials and are likely to have audible manifestations, only to be told it's a useless conjecture by one sociopath and exhorted to die in a fire (twice) by another, a self-styled moderator who can not be put on the ignore list.

Far be it from me to suggest that they both do something profane with themselves, their mothers, and the horses they rode in on. No, I'd never write such a thing here.

[DrStrangelove]

Inexpensive Cryo Treatment services

CryoPlus Inc. in Wooster Ohio does small runs under 1 pound for $17-25 depending on how you specify it (parts? electronics? tools?).

Their generic process includes a 200F pre-heat to remove water, 10 hours at -300F, and a later 300F annealing UNLESS you specify otherwise. 300F is a little close for comfort for the P155 magnet wire insulation (155C = 311F).

CryoPlus Inc contact info:
2429 North Millborne Rd
Wooster, OH 44691
Phone: 330-683-3375
Fax: 330-683-2653
Email: Kathi@cryoplus.com

If you phone later in the day, you are quite likely speaking with the owner, Kathi Bond, so be nice.

[big_teee]

I sent the Strat Single Coil I made for testing, to Rick Turner.
He should have it, by monday.
T

[salvarsan]

I sent the Strat Single Coil I made for testing, to Rick Turner.
He should have it, by monday.
T

bravo, Terry.

The usual way these things happen is a cryo treatment over the weekend and return shipment on Monday and Tuesday.