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Gibson P90 Color Code
Posted: Sat Aug 28, 2021 7:46 pm
by Mossman
I have a set of Gibson P90s that I want to put in my Casino, but these things have FIVE wires coming out of them, and I don't know which ones are hot and ground.
I assume that two of these wires aren't connected to anything, since there's no earthly reason why a P90 needs 4 conductors. They probably use the same leads with Molex connectors for everything, and just disregard the wires they don't need, but I don't want to go all trial and error with this (swapping pickups in a hollow-body is arduous enough), so if anybody knows which wire is what, it would be a big help. I couldn't find much online regarding the P90s, and Gibson diagrams just show where the connector goes, not what each individual wire is for.
Re: Gibson P90 Color Code
Posted: Sat Aug 28, 2021 7:56 pm
by dabbler
It is possible that the pups are tapped allowing you to get different output strengths.
If you are right and 2 of them aren't connected to anything, the following might help you find out what is what.
OK, the information I'm about to share is like gold if you are going to do pickup swaps. Get ready to copy and paste it somewhere handy because it WILL come in handy:
Pickups - What wire does what?
If you've ever bought or been given a pickup and wanted to know how it should be connected, this tip should help. I will explain the process for a single coil but the SAME principle applies to HBs. If it is a 2 wire you will do it for the pickup as a whole, for a 4 wire HB you should do each coil separately.
Tools needed: multimeter (MM) that can read DC, screwdriver (metal).
1. First, connect the MM across the leads in resistance mode to make sure that you have a complete coil (this might be especially important for 4 wire HBs).
2. Connect the MM across the coil leads in DC mode (if you have to set the sensitivity, some MMs do this automatically go for the most sensitive setting).
3. Tap the coil with the screwdriver. Actually, it is not really necessary to touch it, but you must bring the metal of the screwdriver within the coil's field. When you do this, the meter will jump either positively or negatively. When you remove the screwdriver from the field, the meter should jump in the opposite direction.
4. Record the color leads connected to the + side of the voltmeter and the - side. Call the lead connected to the + side of the meter when the voltmeter jumps + the positive side of the coil. Actually, I may have + and - reversed here, but it really doesn't matter ALL THAT MATTERS is that all the pickups you install get installed the SAME WAY. On 2 wire pups, however, if one of the leads is a shield, call that the - lead (shields should always go to ground).
5. Repeat for every other coil/pickup. If the next coil/pickup makes the needle jump negative when you touch it with the screwdriver, then whatever lead you have connected to the - side of the voltmeter is the + lead for that coil/pickup.
When you are done you will know the + and - side of each coil/pickup. In order to make sure what you are installing is in phase with what is already in your guitar, check it too.
I didn't invent this, I got it from a book. But it has made me NEVER have to guess how to wire a pickup!
Re: Gibson P90 Color Code
Posted: Sat Aug 28, 2021 9:34 pm
by Mossman
dabbler wrote: ↑Sat Aug 28, 2021 7:56 pm
It is possible that the pups are tapped allowing you to get different output strengths.
If you are right and 2 of them aren't connected to anything, the following might help you find out what is what.
OK, the information I'm about to share is like gold if you are going to do pickup swaps. Get ready to copy and paste it somewhere handy because it WILL come in handy:
Pickups - What wire does what?
If you've ever bought or been given a pickup and wanted to know how it should be connected, this tip should help. I will explain the process for a single coil but the SAME principle applies to HBs. If it is a 2 wire you will do it for the pickup as a whole, for a 4 wire HB you should do each coil separately.
Tools needed: multimeter (MM) that can read DC, screwdriver (metal).
1. First, connect the MM across the leads in resistance mode to make sure that you have a complete coil (this might be especially important for 4 wire HBs).
2. Connect the MM across the coil leads in DC mode (if you have to set the sensitivity, some MMs do this automatically go for the most sensitive setting).
3. Tap the coil with the screwdriver. Actually, it is not really necessary to touch it, but you must bring the metal of the screwdriver within the coil's field. When you do this, the meter will jump either positively or negatively. When you remove the screwdriver from the field, the meter should jump in the opposite direction.
4. Record the color leads connected to the + side of the voltmeter and the - side. Call the lead connected to the + side of the meter when the voltmeter jumps + the positive side of the coil. Actually, I may have + and - reversed here, but it really doesn't matter ALL THAT MATTERS is that all the pickups you install get installed the SAME WAY. On 2 wire pups, however, if one of the leads is a shield, call that the - lead (shields should always go to ground).
5. Repeat for every other coil/pickup. If the next coil/pickup makes the needle jump negative when you touch it with the screwdriver, then whatever lead you have connected to the - side of the voltmeter is the + lead for that coil/pickup.
When you are done you will know the + and - side of each coil/pickup. In order to make sure what you are installing is in phase with what is already in your guitar, check it too.
I didn't invent this, I got it from a book. But it has made me NEVER have to guess how to wire a pickup!
Thanks... I always figured that with a P90, I could just check for continuity. If there's only two wires connected, then there will only be two wires that will show a reading, and it doesn't really matter which wire you use for ground, as long as the other pickup is wired the same... But yeah, it
could be tapped, and it's been pretty quiet around here lately, so I've been trying to think of some topics for discussion.
I never knew how to determine positive from negative, though... I have saved this for future reference.