Jazz bass back pickup is thin and quiet

[ngnt]

I was playing a fundraiser for my buddy's middle school that he teaches at and brought out one of my MIM jazz basses that I hadn't gigged with yet. I'm not much of a knob turner so everything on the bass is always full on. I realized that it sounded pretty different from what I thought I remembered and thought I forgot to bring in the back pickup. For some reason when I soloed the back pickup it sounded incredibly thin, almost like the strat's out of phase sounds.

Has anyone had this problem or does anyone have any ideas as to what it could be?

 

[Sav'nBass]

Could it be a loose wire on the pup?

 

[ngnt]

I checked all the wiring and didn't seem to find anything abnormal by looking at it. Everything looks to be wired up how the schematics look and connections appear to be solid.

 

[SGD Lutherie]

Sometimes if the pickup's coil has a break in it you will still get sound, and it will be very thin sounding.

You can test this by taking a reading of the pickup on an ohm meter. If you don't get a reading, then the coil is open.

 

[Slevage]

Sometimes if the pickup's coil has a break in it you will still get sound, and it will be very thin sounding.

You can test this by taking a reading of the pickup on an ohm meter. If you don't get a reading, then the coil is open.

If the coil is open, where does the sound come from if there is no current flowing?

 

[SGD Lutherie]

If the coil is open, where does the sound come from if there is no current flowing?

There are so many turns of wire that they capacitively couple with each other. So in essence the pickup turns into a big capacitor, and passes AC, but you can't get a DC reading from it. I just rewound a set of Jazz pickups from 1976. They were both open. The neck pickup actually sounded fine, and the bridge was thin and weak sounding. Jazz pickups often develop a break or short where the wire touches the magnets due to corrosion.

 

[Slevage]

There are so many turns of wire that they capacitively couple with each other. So in essence the pickup turns into a big capacitor, and passes AC, but you can't get a DC reading from it. I just rewound a set of Jazz pickups from 1976. They were both open. The neck pickup actually sounded fine, and the bridge was thin and weak sounding. Jazz pickups often develop a break or short where the wire touches the magnets due to corrosion.

But the signal would be VERY thin. I like to see the Xc​ on that.

 

[ngnt]

I think SGD Lutherie has the right answer here. I didn't realize the bass is still under warranty so when I took it to this repair guy in Lorton, VA, he seemed to think it was something of the sort. He said MIM basses have this problem a lot. So a new pickup was ordered right away. Thanks for the input guys!

 

[tjnkoo]

Just a thought, if you have this problem again you might simply want to try cranking the pickup height up a bit. I know it sounds simple, but a 1/4" higher on the pickup can do a lot.

 

[acebase62]

IME, the closer a J pickup is to the bridge, it can sound a bit thinner.

(This may be unrelated to your situation).

I prefer 60s spacing if I plan to emphasize the bridge pickup.