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I have built (and daily use) 2 brute force speaker magnetizers ... which of course easily magnetize any pickup, what I often do for pickup winder friends.
That said , those 20000 AT promised by the above posted design are not overkill by any means.
Vacuum is the worst magnetic conductor (mu=1) , same applies to "air" and , bad for us, ceramic magnets which are not far from that.
You need 800000 AT/meter to guarantee saturation in a ceramic , so those 20000 AT will cover 2.5 cm= 1 inch.
Remember it's not only the magnet thickness but also any space not filled with iron (or nickel).
Alnico is easier, both because it *is* a magnetic metal so its own mu is reasonably good, and its coercivity (resistance to magnetization/demagnetization) is lower, but you still need roughly 1/4 of the power needed for ceramics.
FWIW my "small" magnetizer does up to 105mm (~4") diameter ceramics, is single phase powered, 220V (~200V DC), some 22/25 A , so it needs around 5 KW and lives at my shop ; the "large" one lives at a friend's Factory because it needs 3 x 380V (~500V DC) at 46 A , so some 23KW , does 150/155 mm magnets (think G12H/V30) , and now I'm building a larger one for 190/220 mm magnets (think EVM15 , E130/140 , etc.) *BUT* haven't finished it yet, because I doubt a regular 3 phase 380V line will be able to power it, and the necessary BIG capacitors for a Capacitive Discharge one are both VERY expensive and not available here.
I *might* import a ready made one from China, but it will cost some U$20/25K FOB (it's not opnly the Power Supply but also the magnetizing coils and yokes) and don't know how much will I have to pay, both in taxes and bribes, to get it to my door, so it's still in standby for now.
I write this to show how magnetizer costs rapidly escalate out of reach once you want to go beyond the smallest ones.
You pickup guys have all the luck
.
That said , those 20000 AT promised by the above posted design are not overkill by any means.
Vacuum is the worst magnetic conductor (mu=1) , same applies to "air" and , bad for us, ceramic magnets which are not far from that.
You need 800000 AT/meter to guarantee saturation in a ceramic , so those 20000 AT will cover 2.5 cm= 1 inch.
Remember it's not only the magnet thickness but also any space not filled with iron (or nickel).
Alnico is easier, both because it *is* a magnetic metal so its own mu is reasonably good, and its coercivity (resistance to magnetization/demagnetization) is lower, but you still need roughly 1/4 of the power needed for ceramics.
FWIW my "small" magnetizer does up to 105mm (~4") diameter ceramics, is single phase powered, 220V (~200V DC), some 22/25 A , so it needs around 5 KW and lives at my shop ; the "large" one lives at a friend's Factory because it needs 3 x 380V (~500V DC) at 46 A , so some 23KW , does 150/155 mm magnets (think G12H/V30) , and now I'm building a larger one for 190/220 mm magnets (think EVM15 , E130/140 , etc.) *BUT* haven't finished it yet, because I doubt a regular 3 phase 380V line will be able to power it, and the necessary BIG capacitors for a Capacitive Discharge one are both VERY expensive and not available here.
I *might* import a ready made one from China, but it will cost some U$20/25K FOB (it's not opnly the Power Supply but also the magnetizing coils and yokes) and don't know how much will I have to pay, both in taxes and bribes, to get it to my door, so it's still in standby for now.
I write this to show how magnetizer costs rapidly escalate out of reach once you want to go beyond the smallest ones.
You pickup guys have all the luck
.
), unfortunately many in the hobby are unwilling to accept modern technology.
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