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Gibson pickup output impedances


Ricochet

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Ok they might all have x turns of #42 enamel copper wire in them..but what gives each one

that unique signature sound...mojo?....winding technique?...magnet?....something else..in the

"we don't know and they are certainly not going to tell us" department?

 

It's the wire, number of turns, magnet type, magnet strength, magnet materials and casting technique, winding technique (ie scattered, balanced or unbalanced coils etc), pole pieces, pole shues, spacers and bobbin materials .. everything!

 

And the mojo.

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Hate to be the bearer of bad news, Ric, but those pickups are highly suspect. They seem to be awfully... grungy. They should look almost identical to the '57 Classic picture posted... do they match up to the nominal 7.4K and 8.0K values expected for BB Pros?

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I measured the resistances of my pickups from the end of the guitar cord;

 

'57 Classic 7.87 K (origins a bit unclear)

BB3 8.51 K (new, retail)

BB1 8.81 K (used, VOS treatment)

 

The BB1 needs some more measurements and thought. Funny how it measures hotter than the BB3.

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That's hella hot for a BB I... you probably don't want to be measuring through the cord. I made a little rig with a 1/4" phono plug on one end and a pair of banana plugs on the other, about 10" of wire. Plugs right in to the guitar's output. Also you need to be sure that the volumes are pegged at 10.

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It's the wire' date=' number of turns, magnet type, magnet strength, magnet materials and casting technique, winding technique (ie scattered, balanced or unbalanced coils etc), pole pieces, pole shues, spacers and bobbin materials .. everything!

 

And the mojo.[/quote']

 

All those Biff, and don't forget the "hype" such as " Burst bucker" "PAF" and "HOT" and "overwound"

and whatever else...the descriptive marketing is what sells pretty much most first time

users that don't really have a clue of what sound they would like, but want to upgrade

from the mediocre set that comes with the guitar they have bought.

 

PAF, how can you patent (again) a pickup that was patented many many years ago

when Seth Lover applied for the patent on the original humbucker in the early 50s.

 

According to my book "Gibson Guitars, Ted mcCarty's Golden Era 1948 to 1966),

states that G*bson did not have exclusive rights to the humbucker patent. Lover's

invention was not so much ground breaking technology but specifically an engineered

hum cancelling design. Although they did NOT have exclusive rights to patent the

humbucker, they did have SOLE rights to the P.A.F. design, and that is what they

are using and advertising to this day.

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That's hella hot for a BB I... you probably don't want to be measuring through the cord. I made a little rig with a 1/4" phono plug on one end and a pair of banana plugs on the other' date=' about 10" of wire. Plugs right in to the guitar's output. Also you need to be sure that the volumes are pegged at 10.[/quote']

 

That rig is a good idea. I've been meaning to make a similar cable, and I think I should have an extra 1/4" Neutrik plug somewhere... but I've been lazy and/or busy.

 

Made a new measurement, this time from the volume pot in the control cavity, BB I 7.67K ohm.

I should blame the cord, Epiphone pots and my '50s wiring for the extra ohm last time... :-({|=

Seriously, even though everything sounds fine I'd better check the pots and wiring again.

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And somehow my registration with LPF(months ago) doesn't get approved' date=' and I still can't post...:-({|=

 

Any others?[/quote']

 

Try sending a note to "Lily", to remind her of your pending reg. That's what I had to do after waiting a couple of months.

 

HTH

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Hate to be the bearer of bad news' date=' Ric, but those pickups are highly suspect. They seem to be awfully... grungy. They should look almost identical to the '57 Classic picture posted... do they match up to the nominal 7.4K and 8.0K values expected for BB Pros?[/quote']

 

7.7 for the neck and 8.2 for the bridge. What do you think?

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Hmmm... close' date=' danged close.[/quote']

 

Yep, but not close enough. A discrepancy in measured ohmage/resistance of 0.1 I could accept. But 0.3 as per neck pickup? I don't think so. To quote Achmed: I've been $简?-ed!

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Ah Dave. This is a subject that is dear to many guitar players hearts/minds and

ears and subject of much controversy. Which is best for what type of music etc.

 

I wish it was that simple' date=' but there is more to it. The magnetic pickup is a

function of several parameters. Helmuth Lemme explains it a bit in his on-line

explanation of guitar pickups..here's a smidgeon of it..

 

[b']Fig. 1. Electrical equivalent circuit of a magnetic pickup [/b]

A real coil can be described electrically as an ideal inductance L in series with an Ohmic resistance R, and parallel to both a winding capacity C. By far the most important quantity is the inductance, it depends on the number of windings, the magnetic material in the coil, and the geometry of the coil.

The resistance and the capacitance don't have much influence and can be neglected. When the strings are moving, an AC voltage is induced in the coil. So the pickup acts like an AC source with some attached electric components

 

He goes on to say that the capcitance/inductance of the guitar cable and to some degree the input impedance

of the amp have some effect on it.

The unknown factor here is the gaussian field G (magnetic flux density) of the Alnico (or ceramic magnet) used. The field strength will increase

the induced voltage in the coil, but it also has an effect on tone as well. Alnico II, Alnico V and Ceramic will all

have a distinctive tone response, even if the same coil is used on all 3 types.

 

Do you agree or disagree?

 

A man after my own heart! I was told once that if you asked me the time, I would tell you how to build a watch. Yes, I agree with your post Carverman, except that the quote you included didn't take into account the effect on the gaussian properties of the string type, which will vary from nickel steel to stainless steel ( which is why bronze strings don't work as well on an electric), and the picking style and attack of the the player.

 

And, of course, there will be some variance if you are oriented at certain angles to the moon and whether the moon is full or in one its other phases.

 

Good one, Carverman.

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I just had a little mail correspondence with the seller. He claims the PUs are from his 1997 Les Paul Faded. Interestingly enough the Burstbuckers were introduced in 2000 and the Pro-version 3 years later... 8-[

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I thought the LP Fadeds were a newer product line too.

 

Just ran again into Fake58 replica part shop that sells PAF decals (and you even get them for free with their aged pup covers!) and all kinds of aged stuff, looks like forgery of Gibson pickups is becoming easier and easier.

 

decals_small.jpg

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I thought the LP Fadeds were a newer product line too.

 

Just ran again into Fake58 replica part shop that sells PAF decals (and you even get them for free with their aged pup covers!) and all kinds of aged stuff' date=' looks like forgery of Gibson pickups is becoming easier and easier.

[/quote']

 

Yes, I know the shop. At least they sell genuine looking PAF decals with gold lettering.

Mine are black and transparant, the mark of a true fake...

 

On another forum someone suggested the difference in resistance(0.3K) was down to the scatterwinding.

However Gibson differentiates between PU outputs within margins of 0.1K. Calling them similar in output but not the same. A difference of 0.3K would make it a totally different PU.

Also resistance is down to length of wire and number of turns, I'm pretty sure Gibson is using fixed resistance values and the scatterwinding is just to influence flux-field yielding a different tone.

 

But as the seller so very elocquently pointed out. I'm just an expert-wannabee...

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Okay, as promised, I measured some more Gibson pickups and here's the updated list:

 

P-90 7.7KO

P-100 neck 6.1KO

P-100 bridge 9.4KO

'57 Classic 7.7KO

Burstbucker I 7.5KO

Burstbucker II 8.0KO

Burstbucker II (#2) 8.1KO

Burstbucker III 8.2KO

Burstbucker III (#2) 8.4KO

Burstbucker Pro neck 7.4KO

Burstbucker Pro bridge 8.0KO

490R 7.7KO

490T 7.9KO

498T 13.4KO

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If you are measuring the DC resistance of the pickup via the o/p jack, remember that you have a 500Kohm resistance in parallel with the pickup. Any resistance in parallel with another will reduce the overall reading. I once made a simple little excel s/sheet for doing the math. I posted it on the old forum....

Edit:

The difference is approx' 2%, so add 2% to the reading obtained at the O/P jack.

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If you are measuring the DC resistance of the pickup via the o/p jack' date=' remember that you have a 500Kohm resistance in parallel with the pickup. Any resistance in parallel with another will reduce the overall reading. I once made a simple little excel s/sheet for doing the math. I posted it on the old forum....

Edit:

The difference is approx' 2%, so add 2% to the reading obtained at the O/P jack.[/quote']

 

TNX Glenn, yeah I was wondering about that. Do you still have that excel sheet?

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Okay' date=' as promised, I measured some more Gibson pickups and here's the updated list:

[/quote']

 

TNX Rot. That will come in handy.

 

Now I'd be interested in seeing a list of the Epiphone equivalents.

 

57CH 8.45K

HOTCH 13.83K

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TNX Glenn' date=' yeah I was wondering about that. Do you still have that excel sheet?[/quote']

 

No mate, sorry. Its not too hard though.

 

The formula is: Rtotal=

(R1*R2)/(R1+R2)

 

Where Rtotal=Actual resistance of the pickup

R1=resistance of the pot (usually 500000)

R2=Measured resistance at the o/p jack

 

As you can see, the value R1 has a +/- 10% tolerance, making it all academic I s'pose #-o

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  • 6 years later...

I am necroing this thread to add the resistance of the pickups I have sitting here (epiphone versions)

 

epiphone stocker stamped with an r label shows:

 

HOTCH(G)

LP:BRIDGE

BHC

 

dc ohms resistance is, 13.67k ohms

 

57CH(G)

DOT:NECK,BRIDGE

LP:NECK

BHC

 

dc ohms resistance is, 8.65k ohms

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