Alnico magnets are made from aluminium, nickel and cobalt, hence the acronym al-ni-co. Alnico is one of the most popular types of magnet used in electric guitar pickups and there are in fact several different types, the main ones being:
- Alnico II (alnico 2)
- Alnico III (alnico 3)
- Alnico IV (alnico 4)
- Alnico V (alnico 5)
- Alnico VIII (alnico 8)
In this article I’ll take you through all the types and the differences in tone and output between them.
Alnico 2 (II)
Alnico II (alnico 2) is the second weakest type of alnico magnet. This means that the magnetic pull is not very strong so the pickups don’t sound particularly dirty compared to the likes of alnico 5 and 8 especially. The tone of alnico II magnets is often described as “vintage” rather than modern due to its lower output.
Alnico II is well known for sounding quite warm and mellow with a good amount of mid-range to give it a fuller sound. It doesn’t have a huge amount of treble response though so isn’t the clearest sounding.
- Tone = warm and loose
- Output = low
Alnico 3 (III)
Alnico III is the weakest type of alnico magnet meaning it sounds the quietest through a clean amp, and the least distorted through a driven amp. Alnico 3 magnets are not as common as alnico 2 or 5 magnets but were used in the original mid-’50s Fender Stratocasters.
Interestingly, alnico 3 doesn’t actually contain any cobalt at all, so really should probably be named AL-NI, rather than AL-NI-CO.
Alnico 3 tends to sound quite dark compared to the other alnico magnets, however it does still have a decent amount of top-end clarity.
- Tone = dark and glassy
- Output = low
Alnico 4 (IV)
Alnico IV (alnico 4) is stronger than alnico 2 and 3, but weaker than alnico 5 and 8. Similarly to alnico 3, alnico 4 is not a particularly popular type of magnet, but it is used in several guitars including the Seymour Duncan Saturday Night Special.
Alnico 4 is often described as having the most balanced EQ.
- Tone = balanced
- Output = low-moderate
Alnico 5 (V)
Alnico IV is very popular and is the second strongest type of alnico magnet. It is often used in more modern electric guitars as it has a brighter tone compared to alnico 2, 3 and 4. This provides it with more clarity and definition which is useful when using distorted amp settings.
Alnico 5 has a higher output compared to alnico 2, 3 and 4 meaning it distorts more easily and sounds louder through a clean amp. Hence alnico 5 is often described as sounding “hotter”.
- Tone = punchy and bright
- Output = moderate
Alnico 8 (VIII)
Alnico VIII (alnico 8) is the strongest type of alnico magnet. Alnico 8 magnets are typically reserved for high-output pickups and sound very aggressive in comparison to the other types of alnico as they distort much more easily so are the closest to ceramic magnets out of all the different types of alnico.
- Tone = bright and aggressive
- Output = high
Tone and Output Comparison
There are two main factors to consider when discussing the overall sound of a pickup, the EQ balance (tone) and the output. Let’s start with the tone.
- Alnico 2: warm and smooth vintage tone
- Alnico 3: dark and glassy tone
- Alnico 4: balanced tone
- Alnico 5: punchy tone
- Alnico 8: bright and aggressive tone
Now let’s discuss the pickup output. Keep in mind though that several other factors including how many coil windings the pickups have will greatly affect this.
Here’s the order from lowest to highest output:
- Alnico 3
- Alnico 2
- Alnico 4
- Alnico 5
- Alnico 8
Lower output magnets such as alnico 2 and 3 are easier to “clean up” and don’t distort as easily. Higher output (hotter) magnets such as alnico 5 and 8 sound louder and more distorted.
This is often why alnico V magnets are used in humbuckers designed for high-gain genres like metal, whereas alnico II magnets are used in vintage humbuckers found on ’50s Les Pauls.
Check out my comparison between low and high output pickups to learn more.
Here is a great video by Darrell Braun Guitar on YouTube comparing the tone of alnico 2, 3, 4, 5 and 8 magnets.
Alnico 2 vs 3
Alnico 3 magnets sound darker and glassier compared to alnico 2 magnets which sound slightly brighter. Alnico 3 magnets have a tighter low-end but less mid-range compared to alnico 2 magnets. Alnico 2 magnets have a higher output compared to alnico 3, meaning they distort more easily.
Alnico 2 vs 4
Alnico 4 magnets have more output and a punchier tone with a tighter low-end compared to alnico 2 magnets. Alnico 4 magnets distort more easily and alnico 2 magnets sound cleaner, quieter and looser by comparison.
Alnico 2 vs 5
Alnico 2 sounds warmer and looser in comparison to alnico 5 which sounds tighter and brighter. Alnico 5 has a higher output meaning it sounds louder and more gritty in comparison to alnico 2 which sounds quieter and cleaner.
Alnico 3 vs 4
Alnico 3 magnets sound quieter and cleaner in comparison to alnico 4 magnets. Alnico 3 magnets sound quite dark and glassy, whereas alnico 4 magnets sound more balanced and more distorted.
Alnico 3 vs 5
Alnico 5 magnets sound brighter in comparison to alnico 3. Alnico 5 also has a higher output so sounds much louder and grittier. Alnico 3 magnets have a smoother top-end and sound more balanced in comparison to alnico 5 magnets.
Alnico 4 vs 5
Alnico 4 sounds more balanced in comparison to alnico 5 which sounds punchier and more aggressive. Alnico 5 has a higher output so sounds more distorted and has a tighter low-end compared to alnico 4 which sounds more rounded and warmer.
Alnico 5 vs 8
Alnico 8 sounds brighter and more aggressive compared to alnico 5 as it has a higher output. This means that alnico 8 sounds more distorted and punchy whereas alnico 5 sounds tamer and cleaner in comparison.
| Magnet | Aluminium | Nickel | Cobalt |
| Alnico 2 | 10% | 19% | 13% |
| Alnico 3 | 12% | 25% | 0% |
| Alnico 5 | 8% | 14% | 24% |
| Alnico 8 | 7% | 15% | 35% |
Check out my comparison between alnico and ceramic magnets