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2011 Traditional tapped P90 - wired wrong - two of them!

BC Audio

Member
Joined
Feb 16, 2010
Messages
119
Can't figure out Gibson "split-coil" P90s

This is the guitar I'm talking about: http://www2.gibson.com/Products/Ele...es-Paul-Traditional-Pro-Split-Coil-P-90s.aspx A special run for GC, apparently. I've had two of these now.

I thought these guitars were wired incorrectly based on my measurements of the resistance of the pickups. But based on listening to them, it seems as though the "tap" in the P90 is not just a tap at some point along a single winding, but that there are two coils, one of which is wound in the opposite direction - or something. I can't find any specs on these pickups.

The DC resistance measurements don't match the specs on Gibson's web site (the link above):

Specs:
Bridge 8.6k, 6.4k tapped
Neck 7.0k, 5.0k tapped

My measurements (taken w/ pickups in the guitar):
Bridge 5.0k, 1.3k tapped
Neck 6.2k, 1.8k tapped

Ok, so the first thing is that the bridge and neck pu's seem to be reversed. But more strange are the super-low resistance numbers. It seemed obvious to me - something was wired wrong.

Here's how each pickup is wired in the guitar. There are three wires from each pickup: bare ground wire, white and black. WHT is connected to the top of the Volume pot, and BLK is connected to the pull switch that shorts to ground when pulled. From this I would surmise that WHT is the full coil and BLK is the tap.

Here's where it gets weird. On the bridge pickup, I measure 5.0k between WHT and GND, 6.8k between BLK and GND, and 1.8k between BLK and WHT. Like this:
GND --- 5.0k --- WHT --- 1.8k --- BLK

Naturally, this lead me to believe that BLK is the top of the winding and WHT is the tap. So I wired it that way. And it sounded awful. The 6.8k "full" winding sounded thin, almost out-of-phase. The 5.0k portion of the winding sounded fuller, with much more low end. So I put it back to stock wiring and commenced head-scratching.

With the pot in the normal position, BLK is not connected to anything. The output of the pickup is WHT.
With the pot pulled up, BLK shorts to GND. So you effectively have GND --- 5.0k --- WHT --- 1.8k --- GND, which is two coils (or portions of the same coil) in parallel. My measurements confirm this, as 5.0k and 1.8k in parallel = 1.3k which is what I measured in the up position.

Anybody have any more info on these pickups? I might just dump 'em and get some good replacements, but I'd really like to know what's going on with these.

Thanks.
 
Last edited:

DanD

Active member
Joined
Apr 8, 2007
Messages
2,368
My Nashville B Bender LP Special has the same wiring set up.

With both knobs down it sounds like classic Gibson P90 tone to me.

With the coil tapped at the neck I can get a single coil tone that a P90 doesn't have. More Fender than Gibson but not quite Fender if you follow me.

My fave is middle position with the bridge tapped and the neck set to full P90. Adds a bit of shimmer and upper end response.

I'd guess that your LPs are wired correctly and that the low reading you are getting is the portion of the coil that is tapped (the wire cut out of the signal chain) to reduce the output of the pickup.

Gibson claims a 2K resistance reduction according to the specs you provided. Your 1.8K reading through the harness is just about what Gibson claims the resistance drop should be. I think you may be reading the resistance drop versus the full tapped portion of the pickup.

Hows does it sound with the coils tapped?

My pups are mellower with a softer output but not anemic. At 1.3 or 1.8K I'd think that either single coil position would be very weak. :peace2
 

BC Audio

Member
Joined
Feb 16, 2010
Messages
119
This guitar definitely sounds weak to me, even in the non-tapped position. I have a 56 Junior and a custom shop TV Model, both of which sound bigger and beefier than this guitar. I contacted Gibson, trying to get more details about these pickups, but they were no help.

I might just pull one pickup out and see what I find. I am quite sure of my measurements, which don't match the specs. My guess is that there was a production change that did not make it into the marketing info. Maybe the 2nd coil was wired backwards, and rather than go back and change it, they decided to change the wiring. Who knows?

Thanks.
 

DanD

Active member
Joined
Apr 8, 2007
Messages
2,368
IDK either... Just seems weird to have gotten two guitars with the same issue.

Mine definitely don't sound weak tho. :hmm

Best of luck. Let me know what you find. :jim
 

MattB4B

New member
Joined
Jun 12, 2023
Messages
2
If anyone has one of these in GOLD they want to sell, hit me up! Cheers...
 

Big Al

Well-known member
Joined
Apr 24, 2002
Messages
14,537
I generaly listen to them first and ignore numbers unless I hear a problem.
 
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