Changing bridge pot?

funkysoul1

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Well after some months with my lovely sg special 2019 i think i need to match the volume balance between those p90s.the have the same output so the neck pickup comes louder.my thought is that gibson put some 300k pots in both pickups.so if just put a 500k or even 1meg pot in bridge volume shall came in balance?dont tell about pickup high-low i have tryed.thanks
 

Go Nigel Go

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So, volume pots might be one way to attack it... Pots are rated by their MAXIMUM resistance value, and a larger value will allow you to reduce output more than a lower value, just remember that the minimum value in almost all cases will be zero, so if you run the pot wide open the resistance will be zero, and the rating on the maximum resistance end of the sweep won't matter at all.

What I would do if I wanted to put a hard ceiling on the output signal would be to use the existing pot to achieve the desired output level, measure the resistance, and get a fixed resister of that value (or a tad lower to be safe) and solder that in series with the variable pot to ensure that is the minimum amount of resistance. So if for example 50 ohms gives you the desired maximum volume, a 50 ohm fixed resistor wired in series with a 300k pot would change its sweep from 0 to 300 ohms to a 50 to 350 ohm range, and the volume would be reduced over the entire range.

Hope this helps. I will say this isn't the typical approach most people would take, but if that is how you want to do it it should work.
 
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Just adjust the pickup heights. A rough guide is that the neck pickup will end up down at the pickguard level. Bridge will be up 1/8" to 1/4".

That's assuming you want to be able to get cleans out of both. If you like to drive hard all the time, bring the bridge up to where you like the sound on 10. Then bring the neck up to match volume.
 

Decadent Dan

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They’re probably 500k now. You could put a treble bleed on the neck pot and turn it down.
 

Huntroll

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Have you measured the D.C. resistance of each pickup to get a handle on what's going on ?

Here's how to do it -

1. Plug in a standard (known/measured good) guitar cable into the guitar.

2. Turn VOLUME and TONE controls fully clockwise.

3. With a DIGITAL VOLT / OHM METER set to the OHMS scale,

Connect -

RED (+) on TIP

BLACK (-) on SHIELD

4. SELECT NECK pickup, document the resistance measured.

5. SELECT BRIDGE pickup, document the resistance measured.

Now, with each pickups coil resistance along with real world performance indications, you can deduce whether or not you will have to replace a pickup to match the output levels better.

You may discover that that guitar has some kind of problem with the wiring by deciphering the pickup coil values.

Make sure there isn't any conductive shielding touching anything HOT inside the control cavity, that would do it.

If I wasn't quite satisfied with how the pickups were, I would have another pickup ready to install the next time I changed the strings.

In your case, I would suspect that the next pickup installed would replace the louder one having slightly less windings, i.e. resistance.
 

funkysoul1

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Just adjust the pickup heights. A rough guide is that the neck pickup will end up down at the pickguard level. Bridge will be up 1/8" to 1/4".

That's assuming you want to be able to get cleans out of both. If you like to drive hard all the time, bring the bridge up to where you like the sound on 10. Then bring the neck up to match volume.
I have done this one but the neck pickup comes so down that I get no attack from it the way I like it
 

skelt101

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@funkysoul1
Your guitar should have 500k pots straight from the factory. I’ve never heard of changing pot values to make a pickup louder. (Perhaps brighter and/or darker…) Unless you want to get into modifying the pickup(s) with different magnets (which is not a big deal in P90s), your best bet is to adjust the pickup heights for balance and fine tune as needed with the volume controls.
 

Go Nigel Go

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@funkysoul1
Your guitar should have 500k pots straight from the factory. I’ve never heard of changing pot values to make a pickup louder.

You have never heard of it because it wouldn't work. :D

Don't confuse resistance inside the pickup with resistance outside the pickup. The resistance inside the pickup is a result of more windings which equals higher output. Resistance OUTSIDE the pickup does not contribute to the signal, it will only attenuate it.

The OP could balance the output levels by reducing the output from the hotter pickup with additional resistance. Most people can get the levels balanced with height adjustment, but he is saying that isn't doing what he wants. Personally I would look at replacing the weaker output pickup with a better match, but a fixed resistor in series with the volume pot could be used to balance output levels. At any rate, it is a cheap modification that could be easily undone at a later date if he wanted to try something else.
 

DrBGood

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dont tell about pickup high-low i have tryed.thanks
Nevertheless ... can you show us where they stand ? What you describe sounds like a textbook P90 height problem.

On my P90 guitars: all their neck P90 sweet spot are where they're adjusted as low as they can go. Definition and clarity.

EPI SP 1.JPG

EPI SP 1+.JPG

PRS SE SOAPAR 1 8.85K 8.9K.JPG

P90 height - 7mm X 4mm.jpg
 
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Col Mustard

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listen to the Doctor!
he knows how to adjust pickup height, and he also knows how to explain it.
P-90 pickups are very sensitive to adjustments in the height.
You don't have to perform surgery on your guitar, and you won't get any benefit if you do.

Me I would adjust all four controls. I like to run my bridge pickup at full volume and run the neck
pickup at about 7 or 8. Adjust the tone controls for less treble at the bridge and more at the neck.
Once I've got t hem balanced this way, I'll play the P-90 guitar with the switch in the middle position
and use a pedal to increases volume for solos or as needed.
 

Colnago

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P90’s have a lot of adjustment in their pole pieces as well. I find that if I lower the entire pickup and raise the pole pieces that it is much different than leaving the pickup at the height the poles are at. Make sense?
Lower the entire pickup and raise the poles vs just lowering or raising the pickup without touching the poles makes a marked difference in output for me.
 

ChubbyFingers

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More ohms in the TONE pot will make the sound brighter, as will dropping to a smaller value tone cap. 0.003uF or even 0.022 uF (as used in single coils). Often a brighter sound can sound louder than a darker one. Other than that try raising one pickup, and just as importantly, lowering the other.
 
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More ohms in the TONE pot will make the sound brighter, as will dropping to a smaller value tone cap. 0.003uF or even 0.022 uF (as used in single coils). Often a brighter sound can sound louder than a darker one. Other than that try raising one pickup, and just as importantly, lowering the other.

A good way to test this is to just disconnect the tone cap. That's the brightest it's going to get with any pot in the tone position.

If that seems better, then consider purchasing a 500K or 1M tone pot. Smaller capacitors mostly just change the curve of the tone pot.
 

funkysoul1

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Nevertheless ... can you show us where they stand ? What you describe sounds like a textbook P90 height problem.

On my P90 guitars: all their neck P90 sweet spot are where they're adjusted as low as they can go. Definition and clarity.

View attachment 49105

View attachment 49106

View attachment 49107

View attachment 49108
I have now 2 guitars and more in the past. None of their Pickups has the same values in both positions. That's the problem. I have tried to take it down but it's losing the attack that a single coil should give. Any way 9,1k as Gibson saying it's too hot for my taste for a neck pickup. I'm very near to replace it with a lower output one. I'm thinking for something around 6,5-7,5k. Thanks all guys
 

flatrockmobile

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I have now 2 guitars and more in the past. None of their Pickups has the same values in both positions. That's the problem. I have tried to take it down but it's losing the attack that a single coil should give. Any way 9,1k as Gibson saying it's too hot for my taste for a neck pickup. I'm very near to replace it with a lower output one. I'm thinking for something around 6,5-7,5k. Thanks all guys
Or a hotter bridge PU.
Gibson just uses the same P90 in both positions. In my case, it doesn't matter bc I rarely use both at the same time but when I do, I just use the volume controls and my ears to get the tone I'm after.
 

Huntroll

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I know my opinion isn't going to be very popular but . . .

P-90's suck !

I don't own a single Gibson with P-90's.

Only a couple of Epiphones I got stuck with.

Gibsons are expensive, I've never been able to justify one with those lousy oversized single coil pickups.

Somebody's got to say it.
 

Decadent Dan

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I know my opinion isn't going to be very popular but . . .

P-90's suck !

I don't own a single Gibson with P-90's.

Only a couple of Epiphones I got stuck with.

Gibsons are expensive, I've never been able to justify one with those lousy oversized single coil pickups.

Somebody's got to say it.
Who better to say your opinion than you?
 

Go Nigel Go

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Who better to say your opinion than you?
Word.
That's not a "dig" or criticism, it is just a statement of fact. Everyone is entitled to their opinions, but all opinions are by nature subjective. I might recommend you examine further facts or try out some more instruments, but at the end of the day if you don't like something there isn't much more to be said.
 


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