Tech Tips: Alnico and numbers

So you’re in the market for some pickups. You pull up Google and start looking. So many options, so many builders. This one says it has AlNiCo III magnets, this other one says AlNiCo V and yet another says it’s loaded with AlNiCo II. What does this mean and what is the difference, really?

Let’s start with what the word AlNiCo even means. AlNiCo is an acronym for a metal blend of aluminum, nickel, cobalt, and iron. The number following AlNiCo represents the proportions of each metal in that blend. For example, AlNiCo V contains 8% aluminum(al), 14% nickel(ni), 24% cobalt(co),  3% copper(not included in AlNiCo acronym), and the balance (51%) is iron. AlNiCo III, and II use different proportions to achieve different magnet strengths and properties.

AlNiCo magnets were invented in the 1920’s as an alternative to weaker Iron magnets. Iron magnets weakened quickly and lost charge easily with shock or temperature changes. Alnico magnets keep a stronger magnetic field over time and are more resilient to shock and heat.

The most popular AlNiCo magnets you will see in guitar and bass pickups are AlNiCo V, AlNiCo II, AlNiCo III, AlNiCo IV, and AlNiCo VIII. Most commonly you will see AlNiCo V and ceramic (which is a different animal and found in many modern, more aggresive pickups).

Leo Fender started using AlNiCo blended magnets in his experimental pickups as early as 1940. In the Blackguard Book, Nacho Baños writes that Leo used AlNiCo III in the early Broadcasters and Teles. Early P.A.F. humbuckers used AlNiCo V or II. Often, builders used what was available at the time and they changed every few years. Fender was notorious for this.

When shopping for vintage style pickups, you will see alnico II referenced often. This blend is used by many pickup makers for vintage reissue pickups. It is similar to AlNiCo III in that it is weaker than the AlNiCo V we hear so often, but the composition and resulting tone is very different.

Alnico V is by far the most used magnet in our shop with 95% of all pickups produced here using that blend. AlNiCo V has a stronger magnetic pull than AlNiCo II or III. This translates into tighter low end response and a more aggressive, edgy tone.

A good way to imagine the difference between Alnico magnets is to compare them to shocks in a car. Alnico II is like a set of worn in shocks, Alnico V is more like a set of stiff shocks, and Neodymium is like a hardtail Harley, translating every bump in the road.

So what do I use?

There are a few considerations here:

1. What sound are you looking for? Vintage style almost glassy cleans and smooth=AlNiCo II or III. AlNiCo V will be a bit more present with more output and a taller resonant peak.  Aggressive, modern, and tight=Neodymium.
2. Are you chasing vintage tone? Look for pickups with vintage style low numbered AlNiCo magnets and vintage enamel or heavy Formvar coil wire to start. Actual vintage Teles and P.A.F. style humbuckers used AlNiCo II, and III.
3. Want to stand out more in the mix? Use AlNiCo V or stronger Neodymium or ceramic.
4. Too much string pull? If your intonation is suffering from magnet pull from the pickups, use a weaker magnet. We don’t run into this problem often, but when we do, it’s usually with Dual Coil bass pickups (they use four AlNiCo V polepieces per string on each pickup). We fix this by replacing the AlNiCo V magnets with the weaker AlNiCo IV.

Here are the most commonly used AlNiCo blends in order of magnetic strength:

1. alnico VIII
2. alnico V
3. alnico II
4. alnico III (which actually has no cobalt and should be named AlNi III)
5. alnico IV

So in conclusion, our NVT Tele set is loaded with AlNiCo V magnets and is more aggressive and modern sounding than our NVT A3. The NVT A3 is more lush, complex, and sweet sounding. There are a few differences in the winds, but the AlNiCo III magnets are the biggest difference between the two. Have fun and experiment aggressively!

Email john@nordstrandaudio with questions or suggestions for future topics.