Low output on bridge pickup?

[Chistopher]

Anyone know what the issue I'm having is with my newly installed JB suffering from low output? All my usual fixes aren't working so I'm a little stumped. Bridge volume of my A4 JB is about equal to the neck A4 59 with the volume rolled back to 3-4.

I've checked for bad solder joints,
I've measured both coils and they read near 8k each
I've tried reinstalling it twice
The pot reads near 500k across input and output when the volume is at 10.
At the output jack neck measures 8k, bridge measures 16k
It's not the toggle switch causing the problem.
The red/white connection is taped off
The issue is not pickup height
It doesn't look like I burned the pot, but you never know
Coils are not out of phase
The tone of the JB sounds more or less like I'd expect
Magnet is properly gaussed.
The screwdriver test has both screw coils tapping to near the same volume, but the slug coil is a lot quieter on the bridge.

Anyone know what the issue is? I would naturally think a bad volume pot if I didn't know for a fact that I didn't torch it. Also the screwdriver thing is throwing me off because it's a lot quieter than having a single dead coil would usually cause. Also the fact I'm still reading the correct DCR at the output jack has me confused

 

[AdrianSD]

Do you get the same if you bypass everything else and wired it directly to the output jack?

 

[Chistopher]

That's the next step, but I won't get a chance to try until Monday night. Now that I think about it my coil splitting test didn't drop too much output, but then again it was quiet to start with as well. But in what situation would a coil be damaged but still read the proper DCR?

 

[freefrog]

A damaged coil can certainly keep working while behaving as a series capacitor but in such a case, there's no DCR reading and the output doesn't drop much, except in the bass range.

Therefore, the only explanation coming to my mind is... non magnetic slugs.

Personally, I'd try to shove six slugs coming from another humbucker in the "quiet" coil. Use the holes of any pickup cover to pull off safely the original slugs if needed (once the baseplate unscrewed and lifted laterally, pushing on each slug while it's above a hole in a cover helps to pull them off easily while maintaining the coils without warping nor ripping them).

HTH. Let us know if the problem was elsewhere...

 

[Chistopher]

I'll add that to the list of things to try, as well as the list of things to experiment with on later builds. Do alnico rods fit in the slots? A homebrew stagmag could be an idea

 

[GuitarDoc]

I wouldn't mess with the slugs, you might damage your pup if you don't know what you're doing. Plus it would be next to impossible to imagine that SD would put in slugs that are different (non-magnetic) from every other slug they have in their shop.

If you've tested each coil and they read ~8k each, that would indicate that there is probably nothing wrong with the pup (except that it's a JB ). Generally when someone has a problem like this and even though they say "I've checked everything and even reinstalled it", it's STILL a problem with their wiring but they're just not seeing it. Probably a bad connection/cold joint or a short somewhere (probably a strand of the black wire touching the red wire). Have a new set of eyes take a look at it. Or post several clear pics which will show every wire, where it's coming from and where it's going, and close up pics of every solder joint/connection and we can take a look for you.

 

[Chistopher]

Hmm... now that I think about it I may be stupid. I will report back when I get in there next

 

[GuitarDoc]

Well, you're not stupid...you just may have overlooked something.

 

[freefrog]

Plus it would be next to impossible to imagine that SD would put in slugs that are different (non-magnetic) from every other slug they have in their shop.

Agreed but I've not said nor suggested it was an error from the factory. The original message mentioned a "newly installed JB", which is not the same to me than a "new" one and might have been bought as a 2d hand PU...

... and it's not as if I hadn't seen 2d hand PU's with missing or non original (and sometimes utterly wrong) "parts". ;-)

Add to this the memory of some experiments done here with variably magnetic materials as coil cores... and you'll know why the strange idea expressed in my previous post came to my mind.

I'll read the following answer(s) with interest, anyway.

 

[Chistopher]

So I took off work early for this , but the problem was not far off from the polepiece theory. I set a large neodymium bar magnet on top of a book on top of the box that the JB came in.

How does one regauss a bar magnet with a bar magnet without removing the pickup? I can't quite get the whole pickup to the same volume. Right now everything except the B string on the JB is fine, but the B is quiet and does a weird volume swell thing. Perhaps residual magnetism in the string?

 

[Chistopher]

Also the volume on the B string cuts out if I touch anything metal

 

[Chistopher]

I fiddled with it and that fixed it. Back to work I go

 

[Mincer]

What was the deal?

 

[Chistopher]

I had accidentally degaussed the magnet by letting it sit too close to a neodymium magnet. Just letting it rest on top of the pickup seperated by a cloth to prevent scratching fixed it.

You can actually completely reverse the phase of the pickup in seconds. It sounds pretty cool to strum a chord and then switch to the Peter Green mod as the chord is sustaining.

 

[GuitarDoc]

Agreed but I've not said nor suggested it was an error from the factory. The original message mentioned a "newly installed JB", which is not the same to me than a "new" one and might have been bought as a 2d hand PU...

... and it's not as if I hadn't seen 2d hand PU's with missing or non original (and sometimes utterly wrong) "parts". ;-)

Add to this the memory of some experiments done here with variably magnetic materials as coil cores... and you'll know why the strange idea expressed in my previous post came to my mind.

I'll read the following answer(s) with interest, anyway.

I get that. Totally understand

 

[jeremy]

neos are strong magnets. keep them away from everything

 

[Clint 55]

You can actually completely reverse the phase of the pickup in seconds. It sounds pretty cool to strum a chord and then switch to the Peter Green mod as the chord is sustaining.

Breh, don't go waving a neo mag at all your pickups. It jacks up the symmetry of the poles. You may get it to work, but it won't be the same as new and will likely be wonky. The neo mag's field extends out quite far and it penetrates through the entire alnico. So the alnico doesn't go yeah my equator is right here and this pole is over here and that pole can only be over there so if you wave a neo at me I'll all of a sudden flip my poles 100% precisely because physics! In reality, for the alnico to be charged correctly you have to use a magnetizer with opposite neos precisely on either side of the alnico. If you want to flip the phase instantly then use a phase switch.