Epiphone Sorento, bridge pickup seemingly very weak

[conorsearl]

I've got an Epiphone Sorento on my bench (some sort of special edition guitar). It's a thin hollow body guitar with mini humbuckers. From what the owner says the pickups are Gibson mini humbuckers. I'm encountering something I've never really noticed before. The high E string is almost sonically invisible on the bridge pickup, especially compared to the B string. If I back the pole out of the pickup on the high E string so it's 3/64's proud of the cover I start to get a more even output between the B and E strings. But it sure looks odd, and is never something I've had to do before.

Also when trying to balance the pickups, I generally start at an 1/8" on the bass side, and 3/32" on the treble then adjust from there. At those measurements the neck pickup sounds sweet, but the bridge pickup is as high as it will go, and sounds like it has about half the output of the neck pickup.

I haven't pulled the pickups out to measure their output yet, because that is going to be a time consuming and annoying job, but from what I've described does this sound like a pickup that is on its way out? I had this guitar in previously for a set up/fret dress, there was a weird ground hum on this pickup, but I hadn't noticed the imbalance so much. Re-flowing the solder on the chrome casing solved the grounding issue, but my gut is saying this pickup might be a lemon...

 

[Blille]

I had that guitar for a while. It’s pretty nice and those are nice pickups. They are Gibson USA minis.

The E vs B thing is strange. Is the guitar stock or was there any electronics work done to it? Any chance only one coil could be working or that it’s wired out of phase?

 

[Mincer]

To me it sounds like there is something wrong, but I wouldn't know until it is on a meter.

 

[conorsearl]

I had that guitar for a while. It’s pretty nice and those are nice pickups. They are Gibson USA minis.

The E vs B thing is strange. Is the guitar stock or was there any electronics work done to it? Any chance only one coil could be working or that it’s wired out of phase?

It definitely could have been worked on before, as I said the pickup had a ground hum when touching the cover, reflowing the solder fixed that. The hookup wire looks a little mashed coming straight off the pickup, like it had been pinched.

I suppose only one coil could be good, I've never experienced that before. Wouldn't the whole thing fail? It's just got traditional shielded wire, so there's split options or anything.

I don't think there's any phase issues, as the pickup only sounds weak when it is the one selected, when both pickups are selected there's no quacky thin sound.

 

[conorsearl]

To me it sounds like there is something wrong, but I wouldn't know until it is on a meter.

Measuring the pickup resistance off of the guitar cable, the neck reads 6.88ohms, and the bridge is 6.28 ohms.

 

[BluesMan335]

does this sound like a pickup that is on its way out?

Pickups don't wear out, no moving parts. I'd try a taller pickup ring, and/or long height screws.

 

[Blille]

It definitely could have been worked on before, as I said the pickup had a ground hum when touching the cover, reflowing the solder fixed that. The hookup wire looks a little mashed coming straight off the pickup, like it had been pinched.

I suppose only one coil could be good, I've never experienced that before. Wouldn't the whole thing fail? It's just got traditional shielded wire, so there's split options or anything.

I don't think there's any phase issues, as the pickup only sounds weak when it is the one selected, when both pickups are selected there's no quacky thin sound.

Thanks.

If it’s just a shielded wire my hypothesis of crappy wiring doesn’t really work. You would be amazed but folks may connect a humbucker oop with itself. Also, the reading being above 6 rules out the one coil hypothesis.

I agree with the height comment, seems like your best option. I would lower the neck.

If just playing with height doesn’t fix it and your customer wants a stronger bridge sound, you may not be able to deliver it with a vintage style pickup in the bridge that has the same resistance as the neck.

 

[conorsearl]

Well, I left the bridge pickup as high as it would go, and dropped the neck down until it matched more closely in output. I much preferred the sound of the neck closer to the strings, but it seems this is the best compromise. Thanks for the help.

 

[eclecticsynergy]

Trying to figure out how the high E could be so much quieter than the B.
With some pickups there'll be a slight difference, but a really noticeable one is another story.

Anybody know if thuse mini hums use a short bar magnet?
Is it possible the mag might've shifted enough to no longer contact the outermost pole screw?
If so you could only be hearing the blade coil for that one string.

 

[eclecticsynergy]

Another possibility is that the magnet in that pickup might've become partially degaussed, perhaps only at the one end.
This seems unlikely but is not impossible. Uneven charge can occur in bar magnets.
And it would also account for lower overall output from the pickup.

You can regauss (or degauss) alnico magnets using a strong modern neo mags, and it often can be done without removing the pickup.
There was a thread on this by forum member Zhangliqun a few years ago - he's the maker of Zhangbucker pickups.
Will try to find my bookmark for it later this evening.

 

[eclecticsynergy]

Found two Zhangliqun posts in my bookmarks about degaussing/regaussing using powerful neo mags.

Here's one about regaussing with the pickup still in the guitar:
https://www.lespaulforum.com/index.p...7/post-1451071

A more detailed one here on the SDUGF (original forum addy wouldn't work - had to correct it to the newer format), this one talks about both degaussing and regaussing.
https://forum.seymourduncan.com/foru...51#post1820751