ANYBODY HERE EVER DO THE T-TOP MOD ON GIBSON 490 PICKUPS?

[andrewsrea]

You can buy 2 NEO magnets and then recharge them. I have a electric magnetizer but i think @Andrewsrea can provide info on how to demagnetize them.

@jtcnj High temp demagnetization is a bit over hyped. I read the temp of the magnet needs to exceed 1000 degrees F to be demagnetized. I believe that is like cherry-red.

Now, the motor of the grinder may have demagnetized it. Bulk demagnetizers are basically a very powerful AC coil and magnetizers are powerful DC sources. I use two Neodymium bricks with 600lbs each of magnetic force to initially charge my magnets and a bulk demagnitiizzer on a variac to 'shape' the final strength.

That said, composition of the magnet affects the flux pattern (magnetic focus). For instance, I can get an A2 sounding as bright as an A5, but more bell-like vs. A5 'cut.'

[mozz]

Also, when playing with magnets, all the Alnico versions have different compositions. Iron can range from 40 to 70 %, and that is going to change the inductance, hence the resonant frequency. Easily measured on any cheap LCR meter. So it is not all magnet strength that is making changes in your sound. These days, i would doubt any Chinese magnets are actually following the old percentage formulas.

[jtcnj]

I turned the magnet so the pickups are now in phase.
The cut end was at the treble end; it is now at the bass end.
I do not hear any difference in the brightness or any change in the sound of the pickup.

I didnt have any way to test or measure if the magnetism was affected by cutting it.
Based on general observation, I'll call this experiment a success.

I do like it a lot, but don't have a true t-top to compare it to.
I have not been able to play with the tube amps cranked up yet to get a real feel for the tones.

[toomanycats]