Need some advice on pickup magnets

[Sylim]

not sure this is the right sub, since it´s about pickups. but it is about modding.

tl;dr - does thickness or length of the magnet impact the pickups behavior in a notable way?

long story:

- bought a new pickup (Dimarzio D Activator 7) to go into my fan fret 7 string
- had to mod the pickup to be slanted so it actually fits
- i put the base plate of the stock pickup onto the new pickup
- but the ceramic magnet of the Dimarzio was glued to its base plate
- i had to use a heat gun and some mangling to get it off
- i heated the base plate, not the magnet directly, and kept the gun about 20cm away
- turned out ok, everything works

- i do notice, however, the lowest string has a weird attack to it
- at the attack there´s a strong "wave" of TOAN, but it quickly dies down
- a bit like a cheap pickup with overly loud attack and zero sustain
- this wasn´t the case with the original stock pickups, so i don´t think it´s the guitar itself

- could the heat have weakened the magnet? would that cause such a behavior?
- also the magnet of the Dimarzio is slightly too short for the slant, i centered it as good as i could
- it covers about half of one of the pole pieces for the lowest and the highest string
- could that mean those pole pieces are not fully magnetized?
- could that cause this behavior?

- been thinking of getting a new magnet, but in germany i can´t find one with the right dimensions
- i need 70mm x 12.5mm x 5mm
- i can only find them with 3mm thickness or over 70mm length
- would a thinner magnet effect the behavior of the pickup?
- or is there a safe way to shorten a ceramic magnet?

 

[KnightBrolaire]

Yes, high heat can weaken the magnet.
Thicker magnets tend to have more output than thinner ones of the same length/width.

You can remagnetize the magnet with a stronger one if you think it's not performing like normal.

The magnet doesn't have to cover every pole, it still exerts a magnetic field larger than the local area above the magnet.

 

[lost_horizon]

- been thinking of getting a new magnet, but in germany i can´t find one with the right dimensions
- i need 70mm x 12.5mm x 5mm

Philadelphia Luthier tools?

- i can only find them with 3mm thickness or over 70mm length
- would a thinner magnet effect the behavior of the pickup?

Yes less volume but only slightly less. I once had a Dimarzio SDS-111 and when the magnet fell off I put it on the wrong way. Had to reorientate it 4 times to get the direction correct.

- or is there a safe way to shorten a ceramic magnet?

Dremel or sandpaper. Magnets are chemically made and uniform.

 

[Sylim]

Dremel or sandpaper. Magnets are chemically made and uniform.

hey thanks for the input. when cutting a ceramic magnet, could the heat get problematic for the magnetic field in any way? i imagine no, but better safe than sorry.

 

[lost_horizon]

hey thanks for the input. when cutting a ceramic magnet, could the heat get problematic for the magnetic field in any way? i imagine no, but better safe than sorry.

Well people love things like rough cast alnico so jagged edges add a little bit of colour to the sound but nothing to write home about.

 

[Das Gitarrenwiesel]

When we need to shorten a ceramic magnet in the workshop we use a plain old glass cutter ... the sort you score and break window glass with. Makes a really neat job.
Ceramic magnets are so brittle that usually any form of grinding causes them to shatter/crumble.
These people will do the magnet you need ...

 

[ElysianGuitars]

This sounds like the magnet isn't long enough and therefore not properly magnetizing the pole pieces under the low string. Ceramic magnets won't be demagnetized by heat, they handle that sort of thing really well.

 

[ElysianGuitars]

Yes, high heat can weaken the magnet.
Thicker magnets tend to have more output than thinner ones of the same length/width.

You can remagnetize the magnet with a stronger one if you think it's not performing like normal.

The magnet doesn't have to cover every pole, it still exerts a magnetic field larger than the local area above the magnet.

It really is best practice to have magnets that are long enough to reach all the pole pieces, or you can experience lower output on the outer most pole pieces.

 

[Sylim]

hey, thanks everybody for the input. i´ll keep it in mind for the future. i have since figured things out, though in a very round about way and everything works perfectly fine and sounds great.

i got me the neck pickup that fits with the bridge pickup i got for this project. it has the same ceramic magnet with the same dimensions. for that one i didn´t use heat to detach the magnet from the base plate, but instead i simply twisted it off. i clamped the magnet in one vice and the base plate i could clamp with a small handy vice. a bit of leverage and it came right off. it was so easy to twist off i just stood there kind of dumbfounded.

so i put that new ceramic magnet into the bridge pickup. this time also making sure it covered most of the pole piece for the lowest string and less for the highest string. because for metal riffs the lowest string just has priority for me for the bridge pickup.

what i first noticed was the sound didn´t actually change noticeably to my ears. so i´m guessing the heat gun method didn´t heat it up enough to have any effect and the coverage of the pole piece missing a few millimeters didn´t negatively effect it either.

i also put the previous magnet from the bridge pickup, that i removed using the heat gun, into the neck pickup now. this time i made sure it covers more of the pole piece for the highest string than the lowest string, because i use that for leads and cleans and here the highest string takes priority for me. but even so, the lowest string still isn´t noticeably weak sounding than the rest. it´s sufficiently loud.

so bottom line i guess there´s not much to worry about when modding pickups as long as you don´t slip and ram a screw driver into a coil. i´m sure that would kill it.

 

[Das Gitarrenwiesel]

hey, thanks everybody for the input. i´ll keep it in mind for the future. i have since figured things out, though in a very round about way and everything works perfectly fine and sounds great.

i got me the neck pickup that fits with the bridge pickup i got for this project. it has the same ceramic magnet with the same dimensions. for that one i didn´t use heat to detach the magnet from the base plate, but instead i simply twisted it off. i clamped the magnet in one vice and the base plate i could clamp with a small handy vice. a bit of leverage and it came right off. it was so easy to twist off i just stood there kind of dumbfounded.

so i put that new ceramic magnet into the bridge pickup. this time also making sure it covered most of the pole piece for the lowest string and less for the highest string. because for metal riffs the lowest string just has priority for me for the bridge pickup.

what i first noticed was the sound didn´t actually change noticeably to my ears. so i´m guessing the heat gun method didn´t heat it up enough to have any effect and the coverage of the pole piece missing a few millimeters didn´t negatively effect it either.

i also put the previous magnet from the bridge pickup, that i removed using the heat gun, into the neck pickup now. this time i made sure it covers more of the pole piece for the highest string than the lowest string, because i use that for leads and cleans and here the highest string takes priority for me. but even so, the lowest string still isn´t noticeably weak sounding than the rest. it´s sufficiently loud.

so bottom line i guess there´s not much to worry about when modding pickups as long as you don´t slip and ram a screw driver into a coil. i´m sure that would kill it.

I had a guy bring me a lovely 1963 Jazz bass pickup for rewinding that had a great cut into the windings ... I asked how it had happened ... and the owner admitted to trying to remove the cover with a wood chisel!
Some time later the guitar tech of a very famous rock band brought me a rather sad Dimarzio pickup that someone (and I never did find out if it was the artist or the tech) had put a drill bit through, apparently while doing some mods to the guitar!
Be careful out there!

 

[Sylim]

I had a guy bring me a lovely 1963 Jazz bass pickup for rewinding that had a great cut into the windings ... I asked how it had happened ... and the owner admitted to trying to remove the cover with a wood chisel!
Some time later the guitar tech of a very famous rock band brought me a rather sad Dimarzio pickup that someone (and I never did find out if it was the artist or the tech) had put a drill bit through, apparently while doing some mods to the guitar!
Be careful out there!

that sounds gruesome how would you even rewind a pickup? wouldn´t that basically make it a completely different pickup? correct me if i´m wrong, afaik the way the coil is wound has an impact on the sound and behavior of the pickup. and replicating that without knowing the coil design seems kind of impossible to me. so rather take the L and buy a new pickup. or am i missing something?

 

[Das Gitarrenwiesel]

that sounds gruesome how would you even rewind a pickup? wouldn´t that basically make it a completely different pickup? correct me if i´m wrong, afaik the way the coil is wound has an impact on the sound and behavior of the pickup. and replicating that without knowing the coil design seems kind of impossible to me. so rather take the L and buy a new pickup. or am i missing something?

You are completely correct that the way a coil is wound has a huge impact on sound and behavior of the pickup. But missing something fairly huge ;-)
The reason people pay people like me to rewind vintage (as well as modern) pickups, and indeed to design and build our own new pickups - is years of research and practical experience ... determining the turns per layer of the original, the wire tile and even tension. These can all be replicated accurately. It's a science not a dark art
My qualification in answering this? 13 years as boss of Oil City Pickups, doing rewinds for artists as diverse as the Rolling Stones and Gorillaz - plus manufacturing pickups used in Black Machine guitars, Carillion Guitars, Flame Guitars, Stone Wolf guitars .... etc etc

 

[Grindspine]

Before getting a new magnet, have you tried simply moving the pickup further from the strings? What you described sounds like an effect I have heard from when a strong magnet is too close to the low string; the magnetic drag changes the attack of the string.