A4 vs ceramic?

[sumitagarwal]

I know that A8, which I've never tried, are usually considered the closest Alnico equivalent to ceramic, but within the more vintage grades of alnico the go-to option for higher gain is the A5.

However, A5's have a more scooped quality to them than the ceramics that are usually used for higher gain tones. That got me thinking: of the traditional alnicos, is the A4 actually more similar to ceramic than A5? Loses some of that bright edge of A5, but is not as scooped and a bit more "sterile" for lack of a better term, like ceramics.

Also, I always thought of A5 as hotter than A4 but James from Rewind pickups claims his PAF-1 A4 model is his highest output PAF, not his PAF-1 A5.

 

[Rex_Rocker]

I don't think Ceramic is more or less scooped than A5. It's just the mid focus is different. Ceramic is all about searing high mids and raspy treble. A5 is more about bite-y rather than raspy/fizzy and softer bass (softer than Ceramic, at leas, as I'm not saying A5 is loose-sounding).

I'd say Ceramic is more broadband than A5 for sure.

If we go all technical, Ceramic does jack up the inductance less, meaning it will be brighter than any Alnico.

 

[Chistopher]

"Hotter" is a marketing term. A5 will often sound louder, but sometimes A4 does, depending on the wind. A large part of what yours ears perceive as volume lies in the midrange, which A4 has more of.

 

[marcello252]

A4 has more a flat eq to my ears, but that doesn't mean boring, instead it is equilibrated

 

[Aceman]

A3 (especially neck) or A4 is go to for more vintage sounds. A5 for standard sounds, rough cast or UOA5's for a different vibe, and A8 for balls/power without being Ceramic.

 

[Rex_Rocker]

"Hotter" is a marketing term. A5 will often sound louder, but sometimes A4 does, depending on the wind. A large part of what yours ears perceive as volume lies in the midrange, which A4 has more of.

I disagree. I don't find it has more mids. Just less highs and lows.

I agree that "hotter" is a very ambiguous way, but what is objective is that A5 is magnetically stronger, thus producing more output.

 

[sumitagarwal]

Hrm, now I'm wondering which magnet would actually drive an amp harder, specifically in the range we normally want to (mids).

 

[freefrog]

Hrm, now I'm wondering which magnet would actually drive an amp harder, specifically in the range we normally want to (mids).

What sets the perceived bass / mids / treble and power of a passive transducer is mainly the charge of its magnet(s) and, in a much lower proportion, the inductivity of the magnetic material(s), itself due to the amount of iron involved.

When a pickup with some ceramic bar(s) sounds scooped, that's because it has the lowest possible inductivity and the highest possible charge compared to other magnetic materials.

All other factors being equal, AlNiCo will be more inductive with a weaker magnetic field.

More inductance shifts down the resonant frequency and contributes to trim the high range.

Less magnetism flattens the EQing curve. The feeling that a magnet gives "more mids" is actually due to less bass and less treble because of the weaker magnetism...

Less treble in the harmonic range (IOW: not in fundamental notes) because of the lower pitched resonant peak but also because the weaker magnetism makes it less strongly voiced.

Less perceived (and not "objective") treble AND bass in fundamental notes because the weaker magnetism makes the field less strong where a pickup concentrates it: at the ends of its coil(s), under the low and high E strings (!) ...


That being said, let's recall how A4 can be characterized comparatively to other AlNiCo alloys and to ceramic. All other factors being equal:

Inductively, A3>A2>A4>A5>A8>Ceramic.

Magnetically, it's the contrary / reverse order (all other factors being equal).

Also: A4 is not that different from A5. it has just a tiny wee bit less of a material in its alloy, making it a tad less efficient than A5 magnetically [EDIT: There's 7% of aluminium in A4, 8% in A5. Hence 52% of iron in A4, 51% in A5. But both include 14% of nickel, 24% of cobalt, 3% of copper... it's the only difference in metallurgy. But they are magnetized differently, making A5 anisotropic VS isotropic A4.]

Can an A4 drive an amp harder than a ceramic bar? Certainly. Charge the A4 to death and rise the pickup close to the strings. Degauss the ceramic bar and lower the pickup.

But the "A4" alloy in itself is certainly not closer to ceramic than A5 is. In fact, A8 is inductively and magnetically closer to ceramic than both...


Hope this rambling doesn't "sound" like a petty lesson. Hope it simply helps by helping to understand what actually happens with magnets.

 

[marcello252]

^ you have to write a book, seriously

 

[freefrog]

Also, I always thought of A5 as hotter than A4 but James from Rewind pickups claims his PAF-1 A4 model is his highest output PAF, not his PAF-1 A5.

BTW and to answer to this part of the original message: James talks about the kind of A4 that HE uses with HIS coils - and all A4 mags are not created equal (or charged equally), as he explained it himself in your topic about low wind P.A.F.'s on MLP (post 7)... Anyway the whole is often more than the sum of its parts IMHO/IME, especially with guitar pickups...

For the record, I've recently mounted a 7,3k bridge PU with an UOA5 magnet: although most people would think it must be weak, it's a firebreather in the guitar where it's mounted. Question of synergy between components.

 

[sumitagarwal]

What sets the perceived bass / mids / treble and power of a passive transducer is mainly the charge of its magnet(s) and, in a much lower proportion, the inductivity of the magnetic material(s), itself due to the amount of iron involved.

When a pickup with some ceramic bar(s) sounds scooped, that's because it has the lowest possible inductivity and the highest possible charge compared to other magnetic materials.

All other factors being equal, AlNiCo will be more inductive with a weaker magnetic field.

More inductance shifts down the resonant frequency and contributes to trim the high range.

Less magnetism flattens the EQing curve. The feeling that a magnet gives "more mids" is actually due to less bass and less treble because of the weaker magnetism...

Less treble in the harmonic range (IOW: not in fundamental notes) because of the lower pitched resonant peak but also because the weaker magnetism makes it less strongly voiced.

Less perceived (and not "objective") treble AND bass in fundamental notes because the weaker magnetism makes the field less strong where a pickup concentrates it: at the ends of its coil(s), under the low and high E strings (!) ...


That being said, let's recall how A4 can be characterized comparatively to other AlNiCo alloys and to ceramic. All other factors being equal:

Inductively, A3>A2>A4>A5>A8>Ceramic.

Magnetically, it's the contrary / reverse order (all other factors being equal).

Also: A4 is not that different from A5. it has just a tiny wee bit less of a material in its alloy, making it a tad less efficient than A5 magnetically [EDIT: There's 7% of aluminium in A4, 8% in A5. Hence 52% of iron in A4, 51% in A5. But both include 14% of nickel, 24% of cobalt, 3% of copper... it's the only difference in metallurgy. But they are magnetized differently, making A5 anisotropic VS isotropic A4.]

Can an A4 drive an amp harder than a ceramic bar? Certainly. Charge the A4 to death and rise the pickup close to the strings. Degauss the ceramic bar and lower the pickup.

But the "A4" alloy in itself is certainly not closer to ceramic than A5 is. In fact, A8 is inductively and magnetically closer to ceramic than both...


Hope this rambling doesn't "sound" like a petty lesson. Hope it simply helps by helping to understand what actually happens with magnets.

This is, very honestly, the most useful write up I have ever read about pickup magnets!! Thank you thank you for your clarity and specificity!

You refer to A5 as anisotropic versus isotropic A4, but an UOA5 is also isotropic and therefor from your description the impression I get is that A4 and UOA5 should be nearly indistinguishable, is that right?

This also got me looking at Wikipedia here: https://en.wikipedia.org/wiki/Alnico#:~:text=The composition of alnico alloys,and the rest is Fe.
I think most people know that Alnico 3 has no "Co". And from my read here it looks like that results in a lower induction, is that correct? Making A3 a more "neutral" magnet overall? Or maybe I'm reading this wrong since you describe A3 as having highest inductivity and ceramic having he lowest.

I'd never read before about stronger magnets emphasizing the E strings, although intuitively this makes sense since those are the furthest from the magnet center and would seem to benefit the most from a larger magnetic field!

How would you describe the difference between isotropic and anisotropic? Is that essentially just an effect on maximum charging strength, and so any tonal differences are down to the level of magnet charge?

 

[freefrog]

This is, very honestly, the most useful write up I have ever read about pickup magnets!! Thank you thank you for your clarity and specificity!

You refer to A5 as anisotropic versus isotropic A4, but an UOA5 is also isotropic and therefor from your description the impression I get is that A4 and UOA5 should be nearly indistinguishable, is that right?

Thx for the kind words. Always glad to help.

Yes, theoretically, A4 should be very close to UOA5.

But practically, even magnets of a "same" alloy can vary according to their age, the foundry where they come from and/or from batch to batch. So perceived variations are to expect, especially when two magnets are NOT of a same alloy.

This also got me looking at Wikipedia here: https://en.wikipedia.org/wiki/Alnico#:~:text=The composition of alnico alloys,and the rest is Fe.
I think most people know that Alnico 3 has no "Co". And from my read here it looks like that results in a lower induction, is that correct? Making A3 a more "neutral" magnet overall? Or maybe I'm reading this wrong since you describe A3 as having highest inductivity and ceramic having he lowest.

The column that you refer to in the Wikipedia page is about magnetic induction in Gauss or milliTesla. My explanation about inductivity was about how magnets change the measured inductance of coils in pickups: A3 is the most "inductive" in this case (because it includes 60% of iron, almost twice more than in a A8). Example: a same 7.8k P.A.F. clone will have an inductance of 4.42H with an A3 bar and 4.14H with a short A5.

I'd never read before about stronger magnets emphasizing the E strings, although intuitively this makes sense since those are the furthest from the magnet center and would seem to benefit the most from a larger magnetic field!

Here is a link about that (the most interesting pics being named "frontal view of A5 singlecoil" and "screw poles for a humbucker"):

https://www.skguitar.com/SKGS/sk/Images/pickups/Pickup stuff/Magnetics.htm

How would you describe the difference between isotropic and anisotropic? Is that essentially just an effect on maximum charging strength, and so any tonal differences are down to the level of magnet charge?

I don't know how I'd describe the difference otherwise than with the usual images but to me, no, tonal differences are not necessarily due only to the charge involved.

For instance, isotropic magnets appear to give a slightly slower attack when impulse response measurements are done... but that's not the kind of tests that one can easily find on the Net, sadly. ;-)

FWIW (my 2 cents ).

 

[sumitagarwal]

Thx for the kind words. Always glad to help.

Yes, theoretically, A4 should be very close to UOA5.

But practically, even magnets of a "same" alloy can vary according to their age, the foundry where they come from and/or from batch to batch. So perceived variations are to expect, especially when two magnets are NOT of a same alloy.




The column that you refer to in the Wikipedia page is about magnetic induction in Gauss or milliTesla. My explanation about inductivity was about how magnets change the measured inductance of coils in pickups: A3 is the most "inductive" in this case (because it includes 60% of iron, almost twice more than in a A8). Example: a same 7.8k P.A.F. clone will have an inductance of 4.42H with an A3 bar and 4.14H with a short A5.



Here is a link about that (the most interesting pics being named "frontal view of A5 singlecoil" and "screw poles for a humbucker"):

https://www.skguitar.com/SKGS/sk/Images/pickups/Pickup stuff/Magnetics.htm



I don't know how I'd describe the difference otherwise than with the usual images but to me, no, tonal differences are not necessarily due only to the charge involved.

For instance, isotropic magnets appear to give a slightly slower attack when impulse response measurements are done... but that's not the kind of tests that one can easily find on the Net, sadly. ;-)

FWIW (my 2 cents ).

This is so cool!! I've always seen magnets compared in terms of balancing frequency response, but that's wild how it allows players to choose their balance of the strings themselves. Really useful aspect for the toolkit that seems to get overlooked!

The faster response of (oriented) A5 would then also be part of why they tend to be favored for more modern or heavier tones compared to the other alnicos, it seems like.