Hello!
My name is Fujioka Takuto, a guitarist who can also perform therapy.
Have you ever modified your guitar?
Don’t you think modifying a guitar is difficult? However, you'll get used to it, once you try it, but at first you may worry about breaking the guitar.
When I adjusted the truss rod for the first time, I was terribly scared like "What if the neck suddenly breaks?" Lol
When it comes to changing the tone, I think that pickup replacement is the first thing to do. However, since the wiring requires soldering, you may not want to touch it if you are not familiar with wiring.
This time, as the title suggests, I found information regarding a way to dramatically change the sound of the guitar, which can be easily done without special skills, so I’m going to try it (^ ω ^)!
Now. The method is "replacing the pickup magnet"! You may think this would be difficult and hesitate, but actually this is really easy!
First of all, I will introduce the required items.
① Pickup
② Screwdrivers (plus and minus)
③ Replacement magnet
④ Acetate tape (tape to protect the pickup)
That’s it!
③ and ④ can be purchased at Sound House, so please check them out.
MONTREUX / Rough Cast Alnico 3 Magnet for HB [9252]
MONTREUX / ACETATE TAPE
Please note that this method can only be applied to those with a bar type magnet such as a humbucker. Also, pickups with a cover may require a soldering gun to remove the cover. It's interesting to look at the pickup on your guitar at this opportunity!
Let's see the process using photos!

First, prepare a pickup.
I’m going to use the front pickup for the YAMAHA SJ500EX.
This guitar has a unique specification with a single coil on the rear and a humbucker on the front. This time, in order to bring the tone of the front humbucker closer to the rear single coil, I would like to replace the magnet with the Alnico 3 magnet, which has the lowest magnetic force.

Remove the four small screws on the back of the pickup.

Then peel off the black tape around the pickup. I originally bought the guitar as a junk item, so the pickup is quite dirty.

When I peeled the tape off carefully, the magnet became visible, and I’m going to remove it.

I pushed the magnet out using a flathead screwdriver. Make sure to push it out carefully and do not damage the pickup.

I managed to get it out without damaging it. The magnet in the back is the one originally installed, and the magnet in the foreground is the one I prepared as the replacement. The length is a little different, but there is no problem with the installation.
At this time, it is important to note the orientation of the magnet. Obviously, since it is a magnet, it has an S pole and an N pole. If the magnet is installed with the S pole and N pole reversed, the sound will different and it gets complex, so pls make sure to note with direction the original magnet was installed. You can also check the polarity by attaching two magnets to check in which direction the new magnet should be inserted.

Then, after confirming the magnet direction, insert the new magnet. At this time as well, be careful not to damage the wires and work slowly.
I went all the way in.

After that, wrap tape around the coils to protect them and you're done!
Finally, I mounted it on the guitar, and I had no problem. I’m so relieved. ( ̄∀ ̄)

Regarding the sound. It changed drastically as if the pickup itself had been replaced. Rather than changing the tone, it feels like the characteristics have changed.
In a good way, the bass has become quieter, and it's refreshing. Since the magnetic force is lower than the original magnet, it seems that distortion does not work well, but I think that the sound is close to a single coil as intended. The sound is completely different from the sound before the replacement.
As it was very easy, I replaced the high-power pickup magnet on another guitar with Alnico 3, as well, and found similar changes.
I think this is the characteristic of Alnico 3. It's interesting~!
I want to try other magnets as well. This is so deep... Lol
As long as you pay attention not to damage the wires and to insert the magnet in the correct direction, it is not a difficult process, so even DIY beginners can easily do it!
Even if you make a mistake in the direction of the magnet, you can just remove it and turn it around!
If you are thinking about replacing the pickup, or if you want to alter your guitar but think that it is a little too difficult, please try this!
Bye now!