Alnico vs. ceramic magnet electric guitar pickups
This is my take on the whole alnico vs. ceramic pickup argument.
Let's first define a few things up front.
Alnico (which should actually be written as AlNiCo,) means a pickup magnet made of aluminum, nickel and cobalt. It is not a company name but rather the three 2-letter abbreviations for what the magnet is made up of.
Ceramic magnets, originally invented in the 1960s, are magnets made of iron oxide and strontium carbonate. It is also a man-made magnet.
An alnico magnet pickup has a number after it that defines its relative strength. The higher the number, the greater the output. The most common for guitar pickup use are 2, 3 and 5. Alnico 2 is usually applied to a "vintage output" humbucker, while 3 and 5 are usually used in single-coil pickups, although 5 is also used in humbuckers. In the Stratocaster, alnico 3 has a lower output but more of a "1950's" tone with higher treble, while alnico 5 has a more "1960's" tone. Generally speaking, most players prefer a pickup with alnico 5 magnets because of its higher output, regardless of whether it's single-coil or dual coil humbucker.
Do ceramic magnets have number grades like alnico? Yes. There is ceramic 1, 5, 8 and 8B. The one most commonly used in guitar pickups is ceramic 8, sometimes known as just C8. What's the difference between the grades? Way too nerdy for me to explain. Here's a chart if you're interested. The layman's way I can describe why C8 is used is because it is "most appropriate for use in a guitar pickup."
This all being said, when people say "alnico vs. ceramic," what that actually means is "alnico 5 vs. ceramic 8."
Which magnet do I prefer?
This literally depends on how the pickup is voiced.
I just bought a brand new Fender Stratocaster that has alnico 5 magnet pickups in it. I also have my 1989 Squier II Stratocaster which does have ceramic magnet pickups in it.
With ceramic, I prefer the sound to be "ratty." I actually like the sound of really cheap ceramic magnet pickups, which is exactly what my '89 Squier has in it. The midrange is too loud, treble ceiling too low, and bass is kinda there and kinda not. The guitar sounds great. Yes, I really mean that. It's a very specific type of Strat sound where once you figure out how to wield it, wonderful sounds happen.
With alnico, I prefer not-to-vintage spec, which is exactly what my Fender Stratocaster has. The pole pieces follow the fingerboard radius (more or less,) and the tonal character has a natural midrange "scoop" going on. Midrange frequencies are a little lower while treble and bass frequencies are a little higher. If you were to look at this on a graphic equalizer, the midrange scoop is slight. Nothing too crazy. And that's good.
Is one magnet better than the other?
It really depends on application.
Players who like in-your-face high output pickups will always go with ceramic magnet humbuckers. For rock and metal, you can't beat having one of those in the rear bridge position of a solid-body guitar. A DP100 Super Distortion is all you need there.
Players who like '50s super-clean twangy Strat tones will always prefer alnico 3 magnet pickups. A compressor effect can always be added in for more pronounced notes without adding any distortion.
Players who like '60s Strat tones will always prefer alnico 5 magnet pickups, as they can promote tube type amp speaker breakup better, and work better with the fuzz effect.
Players who like experimenting with a lot of digital guitar effects will generally gravitate towards ceramic magnet pickups, as they do typically work better there - especially for the more "atmospheric" and "dreamy" type effects.
In the end...
If you're confused between which to use, I'll say this:
Ceramic is ceramic is ceramic. Unless specifically stated otherwise, the magnet will be C8. Strats will still sound like Strats, and pretty much any solid-body guitar with humbuckers in it will be just fine for rocking out with.
With alnico, you have to be a little more careful. It is most likely true you want alnico 5 for everything. Rear pickup, middle pickup if the guitar has one, and front pickup. Personally, I like alnico 5 in Strats and alnico 2 in Les Pauls, but that's just me. You would probably prefer alnico 5 everywhere unless very specifically trying to achieve a vintage-correct sound.