What Could Account For This?

[jrdamien]

Two humbucker coils. One wound with 5720 turns and the other wound with 5600 turns. Same speed, tpl and tension. But the coil with less turns has a higher resistance and the one with more turns has a lower resistance, 4.40 and 4.23 respectively.

Explanations?

[Leo_Gnardo]

Same speed, tpl and tension.

Same wire? Measured at the same temperature?

[jrdamien]

Same wire? Measured at the same temperature?

Yes and yes, within a few degrees (or however much a room might change from body temp). Or how great of a temp change is required to account for this? The coil that has less turns but a higher resistance was wound second, so after the room would have warmed some.

All that is left is mechanical aberration, correct? Or am I not thinking of something?

[David King]

Internal shorts would be the most likely answer followed by stretching.
Temperature is very relevant here too -you can watch the resistance change just while you hold the coil in a warm hand.

[nickb]

Two humbucker coils. One wound with 5720 turns and the other wound with 5600 turns. Same speed, tpl and tension. But the coil with less turns has a higher resistance and the one with more turns has a lower resistance, 4.40 and 4.23 respectively.

Explanations?

Confusing which had more turns would explain it to an error of about 1%. Measure the inductance to confirm the theory.

[Leo_Gnardo]

Temperature is very relevant here too -you can watch the resistance change just while you hold the coil in a warm hand.

Copper coefficient near room temp is approx. 0.4% per degree Celsius. The resistive difference between room temp and held in hand for awhile, say 10 degrees C, can easily be 4%. This used to flummox me something awful, thought I'd wrecked pickups by wax dipping, until I looked it up. Let 'em sit at room temp for a good long while then measure.

[jrdamien]

Confusing which had more turns would explain it to an error of about 1%. Measure the inductance to confirm the theory.

I'm definitely not confusing which has more or less turns.

EDIT: Low meter battery. There is no difference in inductance. Both are at 2.16.

[jrdamien]

Copper coefficient near room temp is approx. 0.4% per degree Celsius. The resistive difference between room temp and held in hand for awhile, say 10 degrees C, can easily be 4%. This used to flummox me something awful, thought I'd wrecked pickups by wax dipping, until I looked it up. Let 'em sit at room temp for a good long while then measure.

Sure, and after having been left alone the coils are now 4.3 & 4.16. And this is what I expect of any coil I wind. But it doesn't seem to account for the difference, though.

[Jim Darr]

Internal shorts would be the most likely answer followed by stretching.

I think David hit the nail on the head...Stretching is more likely especially if hand guided/wound. A short is also possible (machine or hand guided).

It could also be smaller wire OD on the one with higher DC resistance...this can happen even on the same spool. Mic the OD of the two coils at both start & finish to see if wire OD could be the culprit.

Are you machine winding with auto-traverse or hand guiding your wire?

If hand guided, TPLs could be slightly off causing your situation. This would be hard to tell because your off-set is so little. Generally a lower TPL will generate a bigger coil with higher DC resistance even with the same turn count.

[jrdamien]

I think David hit the nail on the head...Stretching is more likely especially if hand guided/wound. A short is also possible (machine or hand guided).

It could also be smaller wire OD on the one with higher DC resistance...this can happen even on the same spool. Mic the OD if the two coils at both start & finish to see if wire OD could be the culprit.

Are you machine winding with auto-traverse or hand guiding your wire?

If hand guided, TPLs could be slightly off causing your situation. This would be hard to tell because your off-set is so little. Generally a lower TPL will generate a bigger coil with higher DC resistance even with the same turn count.

Machine wound, auto traverse, identical tension. Same spool of wire, coils wound back to back.

Maybe it was just an aberration but it's big enough that it's bugging me.

If hand winding TPL could account for this, but it would have to be a rather estranged tpl.

[mozz]

What kind of circuit is the turns counter? Some mechanical ones(reed switches, lever switch) screw up or bounce.

[Jim Darr]

What kind of circuit is the turns counter? Some mechanical ones(reed switches, lever switch) screw up or bounce.

mozz, Very good point!! Didn't think of that.

jrdamien, What type of winder are you using?

[jrdamien]

mozz, Very good point!! Didn't think of that.

jrdamien, What type of winder are you using?

It's a homebrew winder with a mechanical traverse. The counter is digital triggered by an optical sensor.

If anything it's a tension issue or wavering somewhere in the traverse mechanism.

However, after posting this earlier, I've since wound a dozen sets of coils. Everything seems fine...fingers crossed.

It's still bothersome, though.

[JGravelin]

All posts have good insights and considerations. Temp, humidity...2 big variables. Small changes make a difference. I've had - and I think we've all had - similar experiences at points in our career and probably still do from time to time: this is good stuff, really. When in doubt, start again. Customers deserve our absolute best, period!

[jrdamien]

All posts have good insights and considerations. Temp, humidity...2 big variables. Small changes make a difference. I've had - and I think we've all had - similar experiences at points in our career and probably still do from time to time: this is good stuff, really. When in doubt, start again. Customers deserve our absolute best, period!

That is absolutely the bottom line. So, even if 'this' is just me being bothered by an inexplicable deviation and wondering all the things I might not know as to why, it's all in the end of always making great pickups.

And yes, lots of good stuff and online to always have and for others to learn from.