P.A.F. Pickup Secrets: Resistance, Why does it vary?

Vintage P.A.F. pickups vary in resistance readings due to several factors.

The first of these details is the meter used for measuring resistance used by Gibson in the 1950's. The use of the Allen Electric Equipment ohmmeter meant that assembled pickup resistance readings were limited in accuracy by a .5k resolution ohmmeter scale.

Magnet wire in the 1950's was also subject to 14% variation in outside diameter and ohms per foot within the 42AWG tolerance. Modern min./nom. wire reduces this potential variation to 7%. This makes vintage P.A.F. pickups prone to a wider variation in resistance.

Pickups wound at the Gibson Kalamazoo factory in the 1950's were also wound in a building with temperature variations that affected the consistency and accuracy of ohmmeter measurements of pickup coils. This led to inconsistency in assembled pickups resistance readings since coil readings go up and down with temperature variations.

Because of the use of pickup winding machines both with and without autostop counters, vintage P.A.F. pickups vary in turn count for each coil. This contributes to variation in resistance readings as well.

Finally, variation in turns per layer between pickup winding machines at Gibson in the 1950's further increases the possible variation of pickup coils resistance readings.

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Chapter headings:
0:00 Intro
0:34 Resistance readings & P.A.F. pickups
1:21 Unboxing of an Allen E-622 Ohmmeter from 1959
7:44 Variation in resistance in P.A.F. pickups
8:58 Tolerance of magnet wire in the 1950's
10:56 How ThroBak makes pickups with consistent resistance
12:40 Pickup turn count
14:08 Turn per layer variation in coil winders
15:28 Final thoughts on P.A.F. pickup variation
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[mikebledsoe]

*Jon you have a prodigious amount of knowledge about PAF pickups and pickup manufacturing in general. That's why I'm ordering a set of KZ115's from ThroBak when the stimulus checks are cut.*

[gib]

I want one of these ohm meters! Jon, you're a kindred spirit. Thanks for all of the vids that we guitar geeks can savor like fine wine.

[myvintagesunburst]

I've greatfully found the next level of guitar geekdom hero .. thank you sir .

[JC-]

Whoa. Mail in cards still look exactly like that in 2021. That's crazy!

[dougmaia]

Awesome info! Greetings from Burst Lovers!

[fongy]

I expect the calibration of test equipment wasn't taken as seriously as it is today. The compulsory use of Allen equipment at each winding station would have been about the best calibration they would or could muster at the time. Analogue needle registered vu's are hardly the most reliable too. It's no surprise that Lover's PAF's had such a wide range of output readings
Great upload, thank you..

[therealbeel]

Excellent pickup geekery Jon. Love your dedication! thank you. You make me wonder if temperature differences in performance circumstances actually change resistance and therefore the tone of your pickup. I definitely have experienced mushy tone in hot and humid circumstances and crisper tone in cold and dry. Wasn't sure if it was my mind that became crisp or mushy or what :-). But it's interesting to speculate that the actual electronics could indeed be affected.

[andrewthomaskuster]

Thanks for sharing your knowledge! Fun to watch. Question: since the winding machines wound pretty much as the were set up to, and a range of DCR seems to have been acceptable for Gibson, might the Gibson stations have had those ohmmeters just to test for continuity of the pickup coil (check for no wire shorts or breaks) rather than to target a DCR?

[ResoBridge]

So how accurate is that Allen meter? I'm assuming its calibration must have drifted a lot since it was made. And did it come with any specifications as to its accuracy? There must be something quite satisfying using these old tools to re-create a product in exactly the same way it was first made all those years ago.
I would have thought that pickup makers like Gibson in the 50s would have used resistance measurement of the coils as a quick and simple method of checking there was nothing hugely wrong with the wound coils before they assembled them into the finished pickup. A resistance check would tell you very roughly if there were something close to the right number of turns on the bobbin and would show up and open circuit or any massive shorts. Measuring the inductance and self capacitance of the coils would in those days have required much more expensive, slow and cumbersome equipment, just not suited to production line use by semi-skilled workers.
I'm assuming finished coils were never graded in any way, so whether you got a pair of coils on each pickup that were matched, or quite widely different in inductance was purely random happen-stance.

[LudusH]

Nice explanations, I wish you're my neighbor Sir

[somebodyelseuk]

IF they were measuring at the winding stations, they'd be measuring circa 3.5k. Considering PAFs went in to nearly every guitar... well, you're looking at about 3000 coils just for the 'Burst period' LPs which weren't evem big sellers.
I'd think it's more likely they'd calibrate the wire and then maybe check a random coil, rather than testing every pickup.

[LPCustom]

Are you going to fill out the registration/warranty card and mail it in? Did Gibson have an LCR meter?

[thegolfnut]

Ohm alone watching informative videos during the year of the virus.
Question Jon, you take great detail in making your pickups, I have a 2012 LP with 57 Classic pups wound by ps (sticker on the back) in 2012. Being that there are variations in winding, it's difficult to know if a pickup can sound better unless you take the time and trouble to install them into a guitar to hear the difference between the two. What are your thoughts on this? Thanks.

[TheChadPad]

You are a great man. Have you and SDPickups compared notes? If not, I think you should

[LPCustom]

One meter per station Jon? Is that your short term goal..(?) LOL! Great info! Did Gibson have anything resembling an LCR meter?
It'd be great to know what their goal was for pickup specs..

[PurposefulPorpoise]

U measure the entire wire. Wut. Did I hear that right? wow