The reference thread for newbies!

[David Schwab]

UPDATE!
Burning away insulation, I read 0.0022", wich is AWG42 accordingly to various tables.

42 AWG=0.0025", 0.064mm

43AWG=0.0022" 0.056mm.

[EtLa]

...A short in -four- coils? Always in the same exact position? ...unlikely..

First of all at what rpm do you wind?

[Biarnel]

First of all at what rpm do you wind?

Something between 400 and 500 rpm.

[David Schwab]

with 7500 tuns I estimate at least ~4mm of winds.

Maybe that's 750 turns!

Seriously, it looks like 2000 tops to me.

[Biarnel]

Maybe that's 750 turns!

Seriously, it looks like 2000 tops to me.

Be careful: that was the first coil I wound. I gave less turns on top and bottom, and most of the wire is in the center.
More like ( | | ) than [ | | ] !

Anyway, think to the subsequent coils... I made two coils, 2 strings, with 13000 turns (no pics sorry): they are SO FAT they don't fit in a jazz bass enclosure. And they are 3.5kOhm per coil.

Maybe it's the tension, maybe it's the wire... I have to try another spool..

[DrStrangelove]

counter trouble?

Maybe the counter is running too fast, bouncing, and over-counting.
Consider that 7500 winds take 15 minutes at 500 rpm.

How much time to wind these coils?

-drh

[EtLa]

Maybe the counter is running too fast, bouncing, and over-counting.
-drh

yes exactly and shorts

[Biarnel]

Maybe the counter is running too fast, bouncing, and over-counting.

Ok, let's say we don't trust my counter.
Let's just wind a 2-strings coil until we read 3.5kOhm.
Well, I did it (in the jazz-style experiment, when the counter said 13000 turns), and the wire made acoil that was WAY LARGER (say 2mm each side) than the flatwork.

So, even if we don't take the counter in consideration, I need to give the coil too many turns. Who cares if they are 7000 or 14000: they are too many, because the coil was ridicolously large.

Shorts: I don't think this is the main cause. As I wrote somewhere here, I tried DCR on 40cm of my wire and I had 2.9Ohm, expecting 3.6.
But then again, using a micrometer the gauge of the wire seems an AWG42.

[David Schwab]

Anyway, think to the subsequent coils... I made two coils, 2 strings, with 13000 turns (no pics sorry): they are SO FAT they don't fit in a jazz bass enclosure. And they are 3.5kOhm per coil.

I don't know what's wrong, but something is. I posted a photo a P bass bobbin. I didn't wind it, but I'm quite sure it does not have anywhere near 13,000 turns on it. Maybe 8,000. See how much it reads?

You are getting really low readings on really high wind counts.

How many people here have ever wound 13,000 turns on a bobbin? I'm sure there must be some. It was probably 44 gauge, and on a P-90 or something.

13,000 turns is just crazy, and that would not be 3.5K.
You are in distortion guitar pickup range! A PAF type pickup bobbin I wound had 5000 turns, and measured 3.9K. That's 8,000 turns less!

I did a high output pickup with 43 gauge and wound 6000 turns on each coil and that was 7.23K.. Total the pickup was 12,000 turns and measured 14.34K (14,340 Ohms) That's 10.84K more than what you are getting with 1000 less winds.

Do you see a problem here?

[GlennW]

Try this.

Start winding a new coil, and STOP after your counter says you're around 100.
Then remove it from your winder and unwind the whole thing and see if the number of turns you unwound is the same number that your counter said was on it.

I'll bet you a dollar to a dognut you get different numbers.

[Biarnel]

Try this.

Start winding a new coil, and STOP after your counter says you're around 100.
Then remove it from your winder and unwind the whole thing and see if the number of turns you unwound is the same number that your counter said was on it.

I'll bet you a dollar to a dognut you get different numbers.

I had 150 turns on the counter, unwinded everything and ... 144.
It's a good percentage: I think I loss 6 turns in the boring process of unwounding.
Can we exclude the counter now?

[GlennW]

I reckon so. I'll fax you a dognut.

[David Schwab]

Can we exclude the counter now?

Sure, but now we need to figure out how you are winding 13 thousand turns and getting such a low DC resistance...

[madialex]

Sure, but now we need to figure out how you are winding 13 thousand turns and getting such a low DC resistance...

I'm betting very loose tension is the culprit. I cant think of another way getting 13000 turns and being too big for a P-Bass cover??

Along with maybe too much scatter...Too much scatter and loose windings will fill up a bobbin fast.

[Joe Gwinn]

I tried the multimeter over 40cm of my wire, and I read 2.9 Ohm. I expected 3.6 Ohm.

Most multimeters are not very accurate at such low values of resistance. It can also be hard to get good contact to such fine wire. If you measure one centimeter of wire, what resistance value do you get?

Try measuring a 10 meter length, and solder the #42 to some #20 bare wire at each end, with multimeter clipped to the #20 wires.

Also, although you used three different multimeters, a more direct test is to use the multimeter to measure a known resistance, such as a commercial 1% resistor, and see that you get the correct answer.

Ten meters is 32.808 feet, so at 1659 ohms per 1000 feet, the resistance should be 54.4 ohms. So, for the known-value resistor, use something near 50 ohms.

Anyway, the wire (with coating) is 0.0028", which is right for AWG42.. and the guy who sold it keep saying the wire is AWG42.

This part appears to be correct.


You posted a picture of the coil as seen from the top. Could you also publish a side-view picture? Please include a metric scale in the photo. This will prevent any measurement and/or translation confusion questions. Actually, top and side, with rulers, would be best.