Simulated Coil Tap for Single P90 Guitar

asdaven

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If I install a hot P90 in a SG Jr style guitar, is it possible to install a push pull pot with the option to reduce the pickup output by ~50% to get brighter clearer tone? Basically simulate a coil tap? The pickup does not have the additional wiring to do an actual coil tap but dont know if this is possible to run a resister in series though a push-pull?

Thanks-
 

DrBGood

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Tapping a coil requires access to half of it, physically split it.
Getting a boost pedal and setting it bright could get you there.
 

Norton

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you could have that push-pull switch activate a passive high pass filter that cuts the lows and gives you a really different sound.
 

asdaven

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you could have that push-pull switch activate a passive high pass filter that cuts the lows and gives you a really different sound.
What about a push pull switch to activate a resistor to reduce output?
 

skelt101

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@asdaven
I think what you’re asking is theoretically possible. PRS has used a similar setup in their Humbucker guitars to virtually tap one of the coils, sending most of its signal to ground. However, since you’re dealing with one coil, this may have the same affect as simply reducing the volume. In order to get the brighter and clearer tone, you’ll probably need some kind of treble bleed circuit with a capacitor and resistor.
 

asdaven

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@asdaven
I think what you’re asking is theoretically possible. PRS has used a similar setup in their Humbucker guitars to virtually tap one of the coils, sending most of its signal to ground. However, since you’re dealing with one coil, this may have the same affect as simply reducing the volume. In order to get the brighter and clearer tone, you’ll probably need some kind of treble bleed circuit with a capacitor and resistor.
Treble bleed goes between the lugs of the pot. But I wonder what a capacitor would do wired between the pickup and volume pot would do? Of course through a push pull to shut it on and off.
 

Go Nigel Go

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If you know the amount of resistance you want, it would certainly be possible to introduce a fixed circuit with a push pull pot with a resistor or some combination of other components as desired. A simple resistor would behave just like turning down the volume pot to the same value, but I could see some benefit to having the fixed value instantly available with the flip of a switch. I would start by seeing if you can get the desired results with the volume pot and go from there.

If you can't get what you want from the volume pot however, a fixed resistor would likely not give it to you either since resistance is just resistance and there is no "color" to be gained by a simple resistor of a different type alone without some sort of tone modifying bleed circuit as others have stated above.

It is an interesting idea, and would be a fun project to see what you could get. I have a custom built Fender Jazzmaster style guitar with two humbuckers in what is essentially a LP or SG type configuration, which has an additional switchable bypass circuit that has it's own set of volume/tone pots for a lower output "rythm" circuit. I seldom use it (so much so that the pots are getting gunked up), but I hope someday to dig into it and make it something I would use a bit more. I have even considered some sort of active electronics once I decide for sure what I want it to do. So many possibilities so little time... :naughty:
 
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asdaven

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If you know the amount of resistance you want, it would certainly be possible to introduce a fixed circuit with a push pull pot with a resistor or some combination of other components as desired. A simple resistor would behave just like turning down the volume pot to the same value, but I could see some benefit to having the fixed value instantly available with the flip of a switch. I would start by seeing if you can get the desired results with the volume pot and go from there.

If you can't get what you want from the volume pot however, a fixed resistor would likely not give it to you either since resistance is just resistance and there is no "color" to be gained by a simple resistor of a different type alone without some sort of tone modifying bleed circuit as others have stated above.

It is an interesting idea, and would be a fun project to see what you could get. I have a custom built Fender Jazzmaster style guitar with two humbuckers in what is essentially a LP or SG type configuration, which has an additional switchable bypass circuit that has it's own set of volume/tone pots for a lower output "rythm" circuit. I seldom use it (so much so that the pots are getting gunked up), but I hope someday to dig into it and make it something I would use a bit more. I have even considered some sort of active electronics once I decide for sure what I want it to do. So many possibilities so little time... :naughty:
I guess resistance is not going to get the desired effect then. Up the resistance, then the sound gets darker not brighter like a lower output pickup. Now thinking about it the volume pot does the samething as a fixed value resistor would wired in series but in a variable way.

So I guess what I need to look at is a capacitor as a bass cut wired to a on/off push pull in series between the pickup and volume.......the goal is to do the opposite of a Jazzmaster rhythm circuit. Want a more clarity and brighter option. So a fixed value bass cut would be what I could try with a capacitor.

Dont know exactly how a Jazzmaster is wired but they could be wired to 1 meg pots and the rhythm circuit is 250K. Jazzmaster pickups are fat single coils so you could change the 250K to 500K. To me if I had a Jazzmaster, id go with 500K pots and do away with the rhythm circuit. 250K is the norm for single coils but fatter single coils need 500K.
 

Go Nigel Go

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So I guess what I need to look at is a capacitor as a bass cut wired to a on/off push pull in series between the pickup and volume.......the goal is to do the opposite of a Jazzmaster rhythm circuit. Want a more clarity and brighter option. So a fixed value bass cut would be what I could try with a capacitor.
The thing you are trying to do is certainly possible. It won't be quite as simple as putting a capacitor on the volume pot and rockin' on, but it should be pretty simple component wise.

The first and most important step should be to actually GET the sound you want by any means possible, and then try and figure out if you can get it in a simpler way. People have gone as far as taking the guts out of a guitar pedal and building it into the body of a guitar, so really, quite literally ANYTHING is possible if know how you can get the sound you want in some fashion.

A tone bleed will involve at least a capacitor and a resistor or two. Your tone knob is hooked to a pot (variable resistance) with a fixed capacitor and a bit of wiring. Changing the value of the capacitor will change the behavior or the tone circuit, as will changing the value of the resistance with the pot. If you know the circuit path, resistance, and capacitance values you need, all that you need to do is create those fixed values in the desired circuit path and use the push pull pot to send the signal though your new circuit.

My "JazzMaster" is not standard, it is a custom build from aftermarket parts and has Humbuckers rather than single coils wired like a Gibson, the additional Fender inspired "rhythm" circuit effectively does the thing you are trying to do in terms of circuit design, just not in the tone results.

If I get around to working on it one day I will probably start by playing with the capacitor values a bit. I may even take inspiration from the Gibson "Varitone" and build a few "notch filters" into it. The sky is the limit with circuit design, and the only thing that is set in stone is that you can't make electrons do something they don't want to do if they have an easier option. You have to build circuits that make your desired result the most attractive path to the flow of electrons, and they will follow it.
 
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Bad Penguin

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What you could do, is the Reverend Bass contour. Drops some of the bass out passively.
contour.jpg

Another thought would be the Bill Lawrence Q Filter.
 

asdaven

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What you could do, is the Reverend Bass contour. Drops some of the bass out passively.
View attachment 49907

Another thought would be the Bill Lawrence Q Filter.
That makes it a variable bass cut. My idea is a simplier on/off fixed bass cut with like a .005uf cap im thinking.
 

thesjkexperience

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There is a tone pot out there that works like a normal tone. Then you pull it up and it works in reverse. It cuts lows acting like a coil tap. I put those in my Juniors.

Precision Music Technologies makes them. All their products work very well.
 
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smitty_p

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If I install a hot P90 in a SG Jr style guitar, is it possible to install a push pull pot with the option to reduce the pickup output by ~50% to get brighter clearer tone? Basically simulate a coil tap? The pickup does not have the additional wiring to do an actual coil tap but dont know if this is possible to run a resister in series though a push-pull?

Thanks-

Is getting another pickup out of the question?

Here's one with the coil tap lead:

 

Lynurd Fireburd

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Unless his current pickup has been wound for tapability no cap or resistor is gonna give him the ability to cut that coil in half ( or however much you desire). Adding the aforementioned is just gonna get you different tonez, not +/- output from a coil.
 


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