The history of the Aluminum-Nickel-Cobalt magical combination we know so well
Alnico permanent magnets are made from an alloy containing varying percentages of iron, aluminum, nickel, cobalt, copper and sometimes titanium. It is produced in different grades, which offer increased magnetic strength (maximum energy product) and resistance to demagnetizing forces (coercivity). Alnico offers the best temperature stability of any standard magnet material produced, but it is also the most susceptible to demagnetizing forces. It is often selected for modern products that must operate at extremely high temperatures. In guitar speakers, alnico is usually selected to help recreate the sound of ‘50s and ‘60s blues, jazz and rock and roll music.
Electrodynamic Loudspeaker History
One of the first modern-style (electrodynamic or “moving coil”) loudspeakers, the Magnavox, was demonstrated in 1915 by Edwin S. Pridham and Peter L. Jensen. Their 1920 patent application (US Patent 1448279) describes “...an annular coil rigidly connected to a diaphragm. This coil is disposed, so as to be freely movable, in a strong concentric magnetic field produced either by a permanent or an electromagnet.” Today, the vast majority of speakers use permanent magnets; however, in the 1920s the permanent magnets available were relatively weak, and those capable of producing a strong magnetic force were costly and difficult to make. Most early electrodynamic loudspeakers used an electromagnet (also known as the field coil).
Electromagnet vs. Permanent Magnet
An electromagnet is composed of a coil wrapped around an iron core. When DC current passes through the coil it generates a steady magnetic field. Electromagnets may be thought of as temporary magnets that lose their magnetism when power is shut off, while permanent magnets do not require an electrical power source to remain magnetized.
Alnico Magnet Development
In the early 1930s, most of the world was in the depths of the economic downturn known in the US as the Great Depression. Early patents relating to the development of alnico express their objective to provide a permanent magnet composed of relatively low-cost materials, which could be fabricated inexpensively and have superior magnetic characteristics.
In US Patent 2027994 (Applied For: 1/20/1932; In Japan 3/09/1931), inventor Tokushichi Mishima of Japan explains how a strong permanent magnet comprised of nickel, aluminum and iron could be produced economically and with superior magnetic characteristics to the “magnet steels” available at the time, including tungsten, chrome, and chrome manganese. Months later, he added to this the discovery that the addition of cobalt could further improve the magnetic characteristics of the alloy, as well as improving its tenacity and ductility (US Patent 2027996).
An advertisement from QST amateur radio magazine (April 1945, p. 75)
In US Patent 2295082 (Applied For: 6/29/1939; In Germany 12/06/1938), inventor Gottfried Bruno Jonas of the Netherlands explains that an alnico alloy in the anisotropic form can yield a permanent magnet with a 50% to 200% higher maximum energy product than the isotropic version. This is the discovery behind what would become known as Alnico 5. This application was patented on Sept. 8, 1942 in the United States.
Alnico had been developed into a robust permanent magnet by 1939. In that same year, Charlie Christian joined Benny Goodman’s band and is credited with popularizing the electric guitar as a lead solo instrument on par with the trumpet and saxophone, but his Gibson EH-150 amplifier used a field-coil speaker. It was not until about 1947 when Gibson and Fender began stocking their guitar amps with alnico speakers. What could account for such a delay?
Don’t you know there’s a war on?
The Nazis invaded Poland in 1939 and WWII began in Europe. In January of 1942, a month after entering the war, the United States government established the War Production Board to regulate the production and allocation of raw materials. Basic metals including steel, copper, and aluminum were heavily regulated to supply military demand, and only essential civilian products would be allocated a percentage of these metals. In order to stay profitable, many American companies had to shift their production to supply parts and equipment the military needed. For example, Gibson made radar assemblies, glider skids for airplanes and precision rods for use in submachine guns. It would not be until after the war ended in 1945 that many peacetime products could make full use of alnico, the miracle metal.
Kurt Prange (BSEE) is the Sales Engineer for CE Distribution, LLC, in Tempe, AZ (jensentone.com). Kurt began playing guitar at the age of nine in Kalamazoo, MI. He is a guitar DIY’er and tube amp designer who enjoys helping other musicians along in the endless pursuit of tone.
Kick off the holiday season by shopping for the guitar player in your life at Guitar Center! Now through December 24th 2022, save on exclusive instruments, accessories, apparel, and more with hundreds of items at their lowest prices of the year.
We’ve compiled this year’s best deals in the 2022 Holiday Gift Guide presented by Guitar Center.
This full-amp-stack-in-a-box pedal brings a new flavor to the Guitar Legend Tone Series of pedals, Missing Link Audio’s flagship product line.
Adding to the company’s line of premium-quality effects pedals, Missing Link Audio has unleashed the new AC/Overdrive pedal. This full-amp-stack-in-a-box pedal – the only Angus & Malcom all-in-one stompbox on the market – brings a new flavor to the Guitar Legend Tone Series of pedals, Missing Link Audio’s flagship product line.
The AC/OD layout has three knobs to control Volume, Gain and Tone. That user-friendly format is perfect for quickly getting your ideal tone, and it also offers a ton of versatility. MLA’s new AC/OD absolutely nails the Angus tone from the days of “High Voltage” to "Back in Black”. You can also easily dial inMalcom with the turn of a knob. The pedal covers a broad range of sonic terrain, from boost to hot overdrive to complete tube-like saturation. The pedal is designed to leave on all the time and is very touch responsive. You can get everything from fat rhythm tones to a perfect lead tone just by using your guitar’s volume knob and your right-hand attack.
- Three knobs to control Volume, Gain and Tone
- Die-cast aluminum cases for gig-worthy durability
- Limited lifetime warranty
- True bypass on/off switch
- 9-volt DC input
- Made in the USA
MLA Pedals AC/OD - Music & Demo by A. Barrero
Sporting custom artwork etched onto the covers, the Railhammer Billy Corgan Z-One Humcutters are designed to offer a fat midrange and a smooth top end.
Billy Corgan was looking for something for heavier Smashing Pumpkins songs, so Joe Naylor designed the Railhammer Billy Corgan Z-One pickup. Sporting custom artwork etched onto the covers, the Railhammer Billy Corgan Z-One Humcutters have a fat midrange and a smooth top end. This pickup combines the drive and sustain of a humbucker with the percussive attack and string clarity of a P90. Get beefy P90 tone plus amp-pummeling output with the Railhammer Billy Corgan Z-One.
Patented Railhammer Pickups take passive guitar pickups to a new level with rails under the wound strings lead to tighter lows, and poles under the plain strings offer fatter heights. With increased clarity, the passive pickup’s tone is never sterile.
Railhammer Billy Corgan Signature Z-One Pickup Demo
For more information, please visit railhammer.com.
Designed for utmost comfort and performance, the Vertigo Ultra Bass is Mono’s answer to those who seek the ultimate gigging experience.
Complete with a range of game-changing design features, such as the patent-pending attachable FREERIDE Wheel System, premium water-resistant and reflective materials, shockproof shell structure and improved ergonomic features, the Vertigo Ultra Bass takes gear protection to the next level.
The Vertigo Ultra Bass features:
- Patent-pending FREERIDE Wheel System that allows for wheels to be attached on the case in no time, giving you the option to travel with it seamlessly
- Upgraded materials, including a water-resistant 1680D Ballistic Nylon outer shell, plush inner lining and new reflective trim for maximum backstage and night visibility
- Enhanced protection with a shockproof shell structure and heavy-duty water-resistant YKK zippers for protection from the elements
- Improved ergonomics and functionality including added back support and load-lifting detachable shoulder straps with side release buckles
- Flexible storage options with added space for touring essentials