Advice on changing Magnets in a P90 pickup.

markj

I've bought a few different mags from Alegree pickups and want to change them in my P90's.
Firstly do the mags need to touch the screws that run through the pickups and what about the polarity of the mags do they need to run in the same direction?

SteveRobinson

The screws go into a metal keeper and the magnets should touch that, like poles facing. This does of course mean they try to push apart.
https://www.stewmac.com/video-and-ideas/online-resources/learn-about-guitar-pickups-and-electronics-and-wiring/p-90-pickup-kit-with-vintage-style-bobbin/

markj

SteveRobinson said:

The screws go into a metal keeper and the magnets should touch that, like poles facing. This does of course mean they try to push apart.
https://www.stewmac.com/video-and-ideas/online-resources/learn-about-guitar-pickups-and-electronics-and-wiring/p-90-pickup-kit-with-vintage-style-bobbin/

Thank you.

ICBM

I've had to fix several P90s that were not working properly - very weak, thin signal even though the coil metered fine - and in every case it was because the magnets had been changed or the pickup just disassembled for some reason, and being put back the way they 'want' to go with opposite poles together. So don't do that .

Funkfingers

Been there. Fixed that. Many times. Many, many times.

markj said:

I've bought a few different mags from Alegree Pickups and want to change them in my P90s.

Before you remove the stock magnets, mark their orientation. This way, you can easily reinstate them without creating phase issues with a second P90.

markj

After changing the mags in the pickups to roughcast 2 and 4, they sound smoother and a little bit warmer.
With the 2 pickups on together there is a slight drop in volume and the guitar sounds quaky like it's out of phase.
Have I put one of the mags the wrong way round.

ICBM

markj said:

After changing the mags in the pickups to roughcast 2 and 4, they sound smoother and a little bit warmer.
With the 2 pickups on together there is a slight drop in volume and the guitar sounds quaky like it's out of phase.
Have I put one of the mags the wrong way round.

It depends how quiet and quacky... there's a slight volume reduction even when the pickups are in phase, and a hollower tone - there's still some harmonic cancellation.

If it's about half the volume of either pickup and very honky, they're likely to be out of phase.

(Edit - ignore that, it's easier to check as mrkb said below.)

mrkb

I’d put a multi meter reading millivolts onto the output cable and see if the voltage spike is the same when tapping a screwdriver onto the pickup. Thats quick and easy check of phase.

markj

Both of the mags are repelling each other on both pickups.
What have I done wrong?

SteveRobinson

Flip both magnets (outside to in) on one of the pickups, this should put it back in phase with the other.

markj

SteveRobinson said:

Flip both magnets (outside to in) on one of the pickups, this should put it back in phase with the other.

But they won't be repelling each other.

ICBM

markj said:

SteveRobinson said:

Flip both magnets (outside to in) on one of the pickups, this should put it back in phase with the other.

But they won't be repelling each other.

Flip *both* magnets in one pickup.

SteveRobinson

ICBM said:

markj said:

SteveRobinson said:

Flip both magnets (outside to in) on one of the pickups, this should put it back in phase with the other.

But they won't be repelling each other.

Flip *both* magnets in one pickup.

I think that's what I said isn't it?  

ICBM

SteveRobinson said:

I think that's what I said isn't it?  

Yes .

I'm not completely convinced they're actually out of phase if the volume drop is only slight though. I would do what mrkb said first.