SPB-3 Weak Output

[boneslayer]

Hello SD community!

I just installed the SPB-3 pickups in a Fender Mexi P Bass (1998) and I am having an issue. When played, the E and A strings are really hot, but the D and G strings are noticeably quieter. It almost sounds like the difference between active/passive pickups. I am going to exchange them for a new set, on the chance that one of the pickups is just bad. I've tried everything from reversing the wires, flip flopping the pickups, and turning the weak pickup 180 degrees. When I flip flopped the pickups, the E and A strings had the low output, which leads me to believe the actual pickup itself is faulty. Have any of you ran into an issue like this in the past?

Thanks in advance for your help!

 

[Funkfingers]

Re: SPB-3 Weak Output

Welcome to the forum.

The usual things to check are the DC resistance for each coil of the split pickup, the solder joints between the coils and the output conductors and that nothing is being physically shorted.

For one coil to give full signal, its output and ground connections must both be good. If the "good" coil is the one with the white output conductor wire emerging from it, this suggests that there must be a path to ground via the second "bad" coil. Similarly, if the "bad" coil is the one with the white output conductor, this would mean that it is magically passing the signal from the "good" coil without adding any signal of its own. This is, of course, impossible.

You probably have a grounding error somewhere. If the pickup was pre-owned, it may have been repaired incorrectly.

If there were a coil break anywhere, the entire pickup would not work.

Phototographs of the underside of pickup, the pickup cavity and the control cavity would help.

 

[boneslayer]

Re: SPB-3 Weak Output

Thanks for the response! That does make sense, and what had happened was the jumper wire that connects the two was wired incorrectly. I remember looking at the pickups and and diagram and thinking "well that just doesn't seem right" but proceeded to try them anyway. I exchanged them for another set, and the diagram and the physical pickups were a direct match. Put them in today and everything sounds A.O.K!

Thanks for the help, funkfingers!

Keep slayin that bone.