# Help with a quiet pickup



## nnieman (Jun 19, 2013)

I got this guitar wired today
Vintage p13 neck pickup
Old ish Gibson p90 bridge pickup 

The p13 is really quiet.
Like way too quiet.
Like dine the amp to hear it quiet.

What the heck is going on?
Is the pickup due for a rewind?

Thanks

Nathan


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## greco (Jul 15, 2007)

What is the DC resistance on the P13? 
Apparently it should be around 8.0 K ohms or so.


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## nnieman (Jun 19, 2013)

greco said:


> What is the DC resistance on the P13?
> Apparently it should be around 8.0 K ohms or so.


How do I test it without taking it out of the guitar?

Nathan


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## greco (Jul 15, 2007)

Disconnect/isolate and test the ends of the wire from the pickup...in the control cavity or wherever.
One test probe to the ground/shield of the wire and one probe to the "hot"/centre conductor.
Does this make sense?


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## mrmatt1972 (Apr 3, 2008)

That is a very nice looking guitar! Sorry I can't help with the question!


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## nnieman (Jun 19, 2013)

greco said:


> Test the ends of the wire from the pickup...in the control cavity.
> One test probe to the ground/shield of the wire and one probe to the "hot"/centre conductor.
> Does this make sense?


That’s what I thought…. Damn

It’s showing nothing on my meter.

Thanks for the quick response Dave

I guess it will need a rewind!

Nathan


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## nnieman (Jun 19, 2013)

mrmatt1972 said:


> That is a very nice looking guitar! Sorry I can't help with the question!


Thanks!


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## greco (Jul 15, 2007)

nnieman said:


> That’s what I thought…. Damn
> 
> It’s showing nothing on my meter.
> 
> ...


Unfortunate and frustrating...Sorry!
Just to be sure...
Is your meter auto ranging or do you have to set the range?
You have the meter set to DC resistance?


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## nnieman (Jun 19, 2013)

greco said:


> Unfortunate and frustrating...Sorry!
> Just to be sure...
> Is your meter auto ranging or do you have to set the range?
> You have the meter set to DC resistance?


Yesir


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## greco (Jul 15, 2007)

Measure twice...rewind (cut) once


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## markxander (Oct 24, 2009)

You can also always measure a pickup by putting a cable in the jack and testing the tip and sleeve of the other end of the cable

It introduces some extra variables (your switch or pots could be dead etc) but it's a quick and dirty way to see if it's totally broken or not


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## knight_yyz (Mar 14, 2015)

if you have a pedal cable plug it into the guitar jack. measure resistance tip to sleeve.


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## gtrguy (Jul 6, 2006)

Check your wiring- if one of the wires isn't connected (cold solder joint, etc.) you will also read open (infinite resistance). Could be a number of things- measure the pickup directly to eliminate or confirm other possibilities.


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## greco (Jul 15, 2007)

gtrguy said:


> ....measure the pickup directly to eliminate or confirm other possibilities.


See post #4


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## gtrguy (Jul 6, 2006)

greco said:


> See post #4


Won't help if the pickup is connected to a short on a switch or pot. You need the pickup to not be connected to know for sure... or at least one end of it.


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## greco (Jul 15, 2007)

gtrguy said:


> Won't help if the pickup is connected to a short on a switch or pot. You need the pickup to not be connected to know for sure... or at least one end of it.


My (wrong) assumption that the pickup wires would be disconnected/isolated for the measurement.
I edited post #4 for clarity.


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## mhammer (Nov 30, 2007)

What sort of magnetic tug does it have? I think people too often focus on the coil, neglecting that the very best, and most overwound, coils do diddley squat if the magnet isn't there to back them up.


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## nnieman (Jun 19, 2013)

I removed the pickup lead from the switch and connected it directly to a jack.
Same result - super quiet unless the amp is turned up way loud.
Like rattle the neighbours windows loud.

Nathan


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## Wardo (Feb 5, 2010)

I thought this thread was gonna be about after market exhaust systems.


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## Latole (Aug 11, 2020)

nnieman said:


> That’s what I thought…. Damn
> 
> It’s showing nothing on my meter.
> 
> ...


If you hear guitar sound with this pickups , you must have a ohms reading, very high, but you read something.

Also test the good working pickup ; report both reading here.


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## Paul Running (Apr 12, 2020)

If you're at the point of removing the pickup, here's a diagram to indicate disassembly to expose the coil. It's rare for a winding to be discontinuous, other than at the terminations. If you are comfortable with a soldering iron (it will require at least a 60W iron with a large copper-tip to de-solder the cover from the frame), remove the cover for inspection:


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## greco (Jul 15, 2007)

Latole said:


> If you hear guitar sound with this pickups , you must have a ohms reading, very high, but you read something.
> 
> Also test the good working pickup ; report both reading here.


Excellent point!
How can this be happening?
What are the logical/possible causes?
Possibly very weak magnets as questioned earlier by @mhammer ?


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## Latole (Aug 11, 2020)

Possible cause ?
Bad solder , defective coil wire = too much resistance.

So many things we don't know.That is why I ask to read ohms on the working pickups and report here.
Does the meter work well? Does the author of the subject know how to use it well; make good contacts on perhaps oxidized wires/connections ?

Is the pickups selector switch work well ?


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## mhammer (Nov 30, 2007)

Magnets CAN get demagnetized over time It's not as easy to do as accidentally tearing a coil, but it *is* possible. AlNiCo is used because it retains magnetic charge for a long time - enough to be called a "permanent magnet". But it doesn't come out of the ground that way, and has to *be* charged. I've reversed the polarity of Alnico polepieces in pickups of mine by placing a strong neodymium over them. So, their "permanence" is simply a reflection of the last influence they are exposed to.

"Demagnetizer" tools abound. They work their dark magic by alternating magnetic charge in a way that results in a sort of "average" of north and south that adds up to zero or near zero. Leaning a guitar up against the power transformer side of an amp (or near an AC motor) can have a similar effect. The caveat is that, in the land of magnets, small distances mean a lot. That is, after all, why tweaking pickup height 1/16" this way or that has such a big impact. So this is not any sort of alarmist directive to NEVER lean your guitar up against your amp. Just a depiction of things that one doesn't think of mattering, that could have a cumulative impact you never suspected.

Use some light ferromagnetic object to sense whether the weak pickup is also pulling that object with less strength than the other pickup does.

Lastly, as I've had the humiliation of learning the hard way, it is possible to connect the two coils of a humbucker out of phase with each other, resulting in a substantially lower output.


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## nnieman (Jun 19, 2013)

Bridge pickup tests to 7.43
Neck pickup test to .1
Cheap master craft multimeter

The neck pickup is wired straight to jack at the moment

Nathan


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## Latole (Aug 11, 2020)

0.1 ohms ! Pickup is short !!! 

Internal wiring or external wiring ? 
I guess it is external wiring and it could be fixed.

Post picture


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## Paul Running (Apr 12, 2020)

Make sure that you are measuring just the pick-up's DC resistance...isolate it from all external wiring.


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## greco (Jul 15, 2007)

This thread is becoming much more interesting than I expected. 
Unfortunately, my "interesting" is @nnieman 's "frustrating".


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## mhammer (Nov 30, 2007)

nnieman said:


> Bridge pickup tests to 7.43
> Neck pickup test to .1
> Cheap master craft multimeter
> 
> ...


That STRONGLY suggests a short somewhere...unless the neck pickup is some sort of ultra-lo-impedance unit...which I suspect it isn't.


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## Latole (Aug 11, 2020)

Pickups use 2 separate wires or a shielded wire ( picture) ?

IMO it is a shielded wire and there is a short between shield and internal live ( +) wire


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## nnieman (Jun 19, 2013)

My soldering iron is a 40 watt weller 

Here are pics of the pickup
The outer shield (ground) is not really well connected to the bass plate… but there are a couple of strands still connected

Nathan


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## greco (Jul 15, 2007)

nnieman said:


> The outer shield (ground) is not really well connected to the bass plate… but there are a couple of strands still connected


Hopefully this is the cause of the problem as it appears reasonably easy to correct!


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## nnieman (Jun 19, 2013)

Is it still magnetic?
Well I would say yes…. But I have no way of testing the strength of that magnet 

Nathan


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## Paul Running (Apr 12, 2020)

If you believe the magnet is weak, you can try recharging the magnet or replace it however, the continuity issue should be addressed first.


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## nnieman (Jun 19, 2013)

Paul Running said:


> If you believe the magnet is weak, you can try recharging the magnet or replace it however, the continuity issue should be addressed first.


If that frayed ground is the issue then I should get a full reading from the hot to the back of the pickup correct?
Cause it’s reading the same as the end of the ground 

Nathan


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## laristotle (Aug 29, 2019)

nnieman said:


> If that frayed ground is the issue then I should get a full reading from the hot to the back of the pickup correct?
> 
> Nathan


Correct. Skip the wire.


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## nnieman (Jun 19, 2013)

laristotle said:


> Correct. Skip the wire.
> View attachment 395369


Thanks
It’s still reading the same

So there is an issue inside the pickup then?

Nathan


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## laristotle (Aug 29, 2019)

nnieman said:


> Thanks
> It’s still reading the same
> 
> So there is an issue inside the pickup then?
> ...


Seems to be, unfortunately.
Then again, wait for someone to post that has more knowledge.


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## Latole (Aug 11, 2020)

nnieman said:


> Thanks
> It’s still reading the same
> 
> So there is an issue inside the pickup then?
> ...


Be sure meter probes have a good contact with pickups body and solder ; beware of oxydation


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## Latole (Aug 11, 2020)

I can fix pickups if I had it, to say how by the web to a beginner is another story
Desolder the positif and read ohms at pickup between +post and body


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## dwagar (Mar 6, 2006)

I had to have the P90s in my '53 Les Paul rewound. I sent them to Throbak.


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## mhammer (Nov 30, 2007)

I was unfamiliar with the P13, and can't find any info on them in Dave Hunter's _Guitar Pickup Handbook_. They look like a slimmed-down version of the P90, but I can't tell if there are two AlNiCo bars abutting a keeper bar, like the P90, or a ceramic bar underneath the keeper, like so many old Japanese pickups. A Google image search isn't really helping, and although Curtis Novak provides some pics of his P13 type, I have no idea of the magnet arrangement he uses, or even whether it is simly his visual take on a P13 and uses a different actual design.


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## knight_yyz (Mar 14, 2015)

double post


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## knight_yyz (Mar 14, 2015)

@nnieman You answered your own question. The braided wire is ground. If you soldered other end of braid to pot there is no continuity. *A few strands is not enough.* Hard to tell how bad the break is but it looks severed to me. Check continuity between back plate and anywhere on the braid. If it doesn't read zero you need to replace the braid with a second wire, back of pickup to pot. And take a bit of sandpaper and clean off some of the oxidation on the back plate. Measure from the clean spot to the hot. The back plate looks like rotted zinc.


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## Latole (Aug 11, 2020)

knight_yyz said:


> @nnieman You answered your own question. The braided wire is ground. If you soldered other end of braid to pot there is no continuity. *A few strands is not enough.* Hard to tell how bad the break is but it looks severed to me. Check continuity between back plate and anywhere on the braid. If it doesn't read zero you need to replace the braid with a second wire, back of pickup to pot.
> 
> View attachment 395398
> 
> ...


It should not be the issue.
Between + and shielded OP read 0.1 ohms
Answer #25 ; Neck pickup test to .1


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## nnieman (Jun 19, 2013)

Latole said:


> I can fix pickups if I had it, to say how by the web to a beginner is another story
> Desolder the positif and read ohms at pickup between +post and body
> 
> View attachment 395372


What does that accomplish?
Will that show if it’s the wire or something inside the pickup?
I am new to opening pickups so I’m making sure I understand what I am doing.

Nathan


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## nnieman (Jun 19, 2013)

mhammer said:


> I was unfamiliar with the P13, and can't find any info on them in Dave Hunter's _Guitar Pickup Handbook_. They look like a slimmed-down version of the P90, but I can't tell if there are two AlNiCo bars abutting a keeper bar, like the P90, or a ceramic bar underneath the keeper, like so many old Japanese pickups. A Google image search isn't really helping, and although Curtis Novak provides some pics of his P13 type, I have no idea of the magnet arrangement he uses, or even whether it is simly his visual take on a P13 and uses a different actual design.


They are in between Charlie Christian pickups and p90s

it’s an alnico bar magnet with a coil around it.
It’s has a bobbin (not wound around the magnet like a danelectro lipstick pickup).

Nathsn


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## mhammer (Nov 30, 2007)

nnieman said:


> They are in between Charlie Christian pickups and p90s
> 
> it’s an alnico bar magnet with a coil around it.
> It’s has a bobbin (not wound around the magnet like a danelectro lipstick pickup).
> ...


Interesting. Some of the pics show a closed top, like yours, and others show adjustable screws, like a P90. I used to have an old Melody Maker pickup and it was also a vertical bar magnet, plunked in the middle of a bobbin, except that the coil was about the size of a Strat coil, rather than wider like the P13. Thanks for the info. You learn something new every day.


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## laristotle (Aug 29, 2019)

nnieman said:


> What does that accomplish?
> Will that show if it’s the wire or something inside the pickup?


Ah, yes. I didn't think of that.
If the wire is the problem, desoldering (or snipping) will become obvious when taking a reading of the pup.


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## Latole (Aug 11, 2020)

nnieman said:


> What does that accomplish?
> Will that show if it’s the wire or something inside the pickup?
> I am new to opening pickups so I’m making sure I understand what I am doing.
> 
> Nathan


Read well ; *do not open the pickups*

If I understand correctly (because the conversation is going in all directions...) you don't know yet if the problem is with the wires or the pickup.

I suggested that you unsolder the positive wire end of the pickup's solder "bubble". Answer #40 
This is must to start there

This way the wire and the pickup will be isolated/separated.

Then measure the ohms between the pickup's solder bubble and the pickup's body.
Report


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## greco (Jul 15, 2007)

Latole said:


> Read well ; *do not open the pickups*
> 
> If I understand correctly (because the conversation is going in all directions...) you don't know yet if the problem is with the wires or the pickup.
> 
> ...


As @knight_yyz suggested in the past, won't cleaning/scraping the solder bubble and some of the back of the pickup and then testing with the with the probes on the cleaned/scraped areas accomplish the same thing?
Doing the above eliminates the potential for the wire being the problem...Correct?
The oxidation could be dramatically influencing the meter readings...Correct?


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## laristotle (Aug 29, 2019)

greco said:


> Doing the above eliminates the potential for the wire being the problem...Correct?


If the short is in the wire, it would still register as a short across +/ - of the pup. Would it not?
Makes sense to disconnect the wire from one of the points of contact, I'd would think.


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## Latole (Aug 11, 2020)

greco said:


> As @knight_yyz suggested in the past, won't cleaning/scraping the solder bubble and some of the back of the pickup and then testing with the with the probes on the cleaned/scraped areas accomplish the same thing?
> Doing the above eliminates the potential for the wire being the problem...Correct?
> The oxidation could be dramatically influencing the meter readings...Correct?
> View attachment 395470



No !


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## Latole (Aug 11, 2020)

laristotle said:


> If the short is in the wire, it would still register as a short across +/ - of the pup. Would it not?
> Makes sense to disconnect the wire from one of the points of contact, I'd would think.


100% right It is the first thing to do. 
Too much not helpful answer here........


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## greco (Jul 15, 2007)

Latole said:


> Too much not helpful answer here........


OK ...Agreed ...Get rid if the wire as it eliminates it as a source of the problem all together.

However, @Latole you should know very well how much a bit of oxidation can influence meter readings and at least support/ agree to the scraping/cleaning as suggested by @knight_yyz. That is a very helpful "answer"/ suggestion IMO!!


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## greco (Jul 15, 2007)

laristotle said:


> If the short is in the wire, it would still register as a short across +/ - of the pup. Would it not?
> Makes sense to disconnect the wire from one of the points of contact, I'd would think.


You are correct in trying to eliminate the shielded wire as the possible source of the issue. 
Personally, I think it is unlikely with braided shield wire but that wire is certainly in rough shape for sure.
I was up much more early than usual and had not had adequate coffee when I wrote that post. How is that for a lame excuse! LOL!

Of nerdy but related interest, I have tried to get solder to soak through the push back cloth insulation of the centre conductor as I often worried that it could happen when soldering the braided shield to the backs of pots...never happened.


Interesting thread!


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## Paul Running (Apr 12, 2020)




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## knight_yyz (Mar 14, 2015)

if the ground was shorted to the positive your reading would be dead zero. 0.1 ohms is not a short!! @nnieman , are you sure your meter rreading was 0.1 and not 0.L? some meters show 0.L as open circuit. 0.1 ohms means something is getting through, like a short with a resisitor bleeding through....

And Latole you are absolutely wrong on the oxidation point made by myself and laristotle. Oxidation and rust affect the reading if you are not making contact. how can you say you worked in electronics field and not know that? If you want a proper reading you want bare metal!!!

I would clean the backplate with a wirebrush or sandpaper, then check for continuity between the ground solder blob and the neck plate for a cold solder joint ( it could also be completly oxidized) I would also check from the neck plate to the farthest end of the braided wire. Should also be zero ohms. Anything higher than zero is a bad ground. If you find the braid wire to be insufficient solder a helper wire from the blob to the pot. Thats assuming the blob has continuity to the plate. If it does not, then solder wick the blob clean the back plate and resolder the blob to the neck plate. 

If all that is good then I would think about taking it apart.


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## greco (Jul 15, 2007)

knight_yyz said:


> 0.1 ohms means something is getting through


Of interest/significance, there was some sound being created when the pickup was attached directly to the output jack.


knight_yyz said:


> And Latole you are absolutely wrong on the oxidation point made by myself and laristotle.


I was totally and frequently supporting you on this also.


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## Paul Running (Apr 12, 2020)

knight_yyz said:


> if the ground was shorted to the positive your reading would be dead zero. 0.1 ohms is not a short!!


Unless the meter is zeroed, he is measuring the resistance of the test leads...it is considered a virtual short.


greco said:


> Of interest/significance, there was some sound being created when the pickup was attached directly to the output jack.


An open coil can produce an output, depending on the number of windings in the continuous section , the coil will produce an audible output through stray magnetic induction.


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## laristotle (Aug 29, 2019)

knight_yyz said:


> oxidation point made by myself and laristotle


That was greco, not me.


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## greco (Jul 15, 2007)

Paul Running said:


> An open coil can produce an output, depending on the number of windings in the continuous section , the coil will produce an audible output through stray magnetic induction.


WOW! Very interesting and educational. Thanks!


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## nnieman (Jun 19, 2013)

I cleaned a spot on the baseplate & disconnected the lead wire.
I am getting no reading on the multimeter
I assume the .1 reading was a fluke I guess?

Nathan


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## greco (Jul 15, 2007)

nnieman said:


> I assume the .1 reading was a fluke I guess?


This pun(?) is intended...
(Sorry ...I couldn't resist)


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## TJSilljer (Aug 30, 2015)

I have had lots of touring guys send me pickups from out your way. Mail it over and I will fix it for ya for free.


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## nnieman (Jun 19, 2013)

TJSilljer said:


> I have had lots of touring guys send me pickups from out your way. Mail it over and I will fix it for ya for free.


Hey thanks!
I appreciate the offer.
I already dropped it off at my friend Lewis shop. (Easy city guitar co)

Nathan


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## MarkM (May 23, 2019)

nnieman said:


> Hey thanks!
> I appreciate the offer.
> I already dropped it off at my friend Lewis shop. (Easy city guitar co)
> 
> Nathan


What's happening with this guitar, I am infatuated by it!


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## nnieman (Jun 19, 2013)

MarkM said:


> What's happening with this guitar, I am infatuated by it!


Nothing yet !
I am waiting to hear if the pickup needs a rewind or not!





it’s sitting in my basement all strung up and no place to go!

Nathan


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## MarkM (May 23, 2019)

nnieman said:


> othing yet !
> I am waiting to hear if the pickup needs a rewind or not!
> 
> 
> ...


Anticipation is making me wait!


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## nnieman (Jun 19, 2013)

Thanks to Guelph Guitar Repair the pickup has a clean bill of health!!
It sounds fantastic!!
Not as thick and wooly as a p90 - it’s very clear and transparent.
More like a Charlie christian pickup then a p90.
That makes sensethe p13 is the step in between the Charlie Christian and the p90.

It’s louder than I expected too - I’m going to have to raise the bridge pickup up.

Nathan


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## MarkM (May 23, 2019)

That turned out great, appreciate you sharing the finished product. What wood did you make the body and neck with?


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## nnieman (Jun 19, 2013)

MarkM said:


> That turned out great, appreciate you sharing the finished product. What wood did you make the body and neck with?


Thank you!
Maple neck with wenge fretboard 
Body is chambered mahogany with a maple top.
It is almost totally hollow - very loud acoustically.
My digital scale recently died but it’s quite light. Body alone was about 5 lbs.

Nathan


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