Why my pickups always get a higher resistance

[aagun918]

Theoretically,42 AWG heavy formvar wire with 8000 turns will gives pickup about 6.0K DC,
but I made three 8000 turns pickups,three of this have DC resistance about 6.3k.
If i wind to 8600 turns,the resistance will increase to 6.8K.
Is there some problems with my winding way?

[big_teee]

Lots of variables with Strat SCs.
Here are some of them.
Bobbin Height.
Wire Diameter, and Ohms per foot.
Tension and scatter.
If I were guessing, I would say your wire is on the small size, and you are scattering quite a bit!
T
Anyone got anything they want to add, please do!

[rjb]

This may sound silly, but what was the temperature when you measured the pickups?
Wire resistance per length is specified at 20 degrees C.
Copper resistivity increases with temperature.
I'm too sleepy to run an example right now, but room temperature really can make a noticeable difference in measured resistance.
(I assume you didn't measure right after potting the pickups in hot wax.)

At any rate, I wouldn't consider a DC resistance 5% over theoretical value to be anything to worry about.
But I'm not exactly a perfectionist.

-rb

[Alberto]

±5% is good for me as well.

[aagun918]

Thanks T,I use Elektrisola 42AWG(Diameter: 0.0029") heavey formvar from ramington industries on Eaby.I think it's quality,and I don't think the scattering was overdone.

You talked about the tension, maybe I take too much pulling force and Diameter was changed,I'll try on the problem you said.

[aagun918]

Maybe I think too much.Thank you RB.

[big_teee]

If your bobbin height is a little short, less than 11mm, or .435 inches, between the flats?
That will make you coil diameter bigger.
The larger diameter the 8000 turns, the more wire length it takes to fill the bobbin.
A taller bobbin will keep the turns small, with less wire to fill the bobbin.
Please measure your bobbin height.
Your HP wire Is good, I've used a lot of it.
GL,
T

[aagun918]

Thanks T,hope I can do it better.( ∙̆ .̯ ∙̆ )

[Lollar Jason]

Other than air temp, tensioning the coils during winding will heat the wire up so initially after winding they will read higher than if you let them sit for 24 hours- could be that. Resistance will vary anyway. if you keep the TPL consistent, consistent number of turns and consistent magnet type with consistent charge with the same coil dimensions your resistance can vary but the inductance will be very close.
Want a coil to read higher?- hold it in your hand for a few minutes. Resistance is futile. Well almost

[mozz]

Was just going to say, if you measure them as soon as they are done, they will read higher. Let them sit for a hours or so and the reading will go down.

Also, as was said, more tension stretches the wire and increases the resistance. You can also have a counter problem that is not reading correctly.

[big_teee]

On tension, that is debatable.
A tight coil will read less than a loose coil.
Provided you're not stretching the wire.
A tight coil will have less overall length of wire than a loose coil.
I agree about the warm coil versus a cool coil at 68-70F degrees.
As mentioned Ohms doesn't mean a lot, unless that is all you have to go by.
I wound that way for years!
However, try to convince the average non winding guitarist, not to pay attention to DCR?
Some can quote the dcr of most pickups.
An interesting conversation, please keep it going!
T

[aagun918]

If your bobbin height is a little short, less than 11mm, or .435 inches, between the flats?
That will make you coil diameter bigger.
The larger diameter the 8000 turns, the more wire length it takes to fill the bobbin.
A taller bobbin will keep the turns small, with less wire to fill the bobbin.
Please measure your bobbin height.
Your HP wire Is good, I've used a lot of it.
GL,
T

Today I wind a 8000 turns pickup with Single Enameled Copper in the same way.
The DCR shows 5.9k.Maybe that's the reason of my problem.

[LtKojak]

Today I wind a 8000 turns pickup with Single Enameled Copper in the same way.
The DCR shows 5.9k.Maybe that's the reason of my problem.

That's textbook for 8K turns of AWG#42 wire. I fail to see a problem here.

[big_teee]

You're just seeing the effect of wire size, & ohms per feet of wire.
Also Bobbin height, tension, & amount of scatter all effect over all pickup DCR.
The simple answer?
If you want less DCR for a neck pickup, then less turns.
If you want more DCR for a bridge Pickup, then more turns.
Most guys wind Strat pickups for body position.
As summarized, you don't have a problem.
T
** More importantly, is to figure out tonally, how many turns sounds best with your wire, and winding style in each pickup position.
I have that charted out for my own style of winding, for my purposes.
If I make a bridge pickup, I know what bobbin height, and how many turns.
If I make a neck pickup, I know height and turns for it, etc.
Since I hand guide, and hand tension, that pretty much stays the same.