Steve?s Special rewind

[HCGUITARS]

Hi Guys,
This is my first contact.
I am a Braziliam luthier and I have to rewind a very injuried DiMarzio Steve's Special Pickup.
The Pickup was badly rewind before by another person and looses the original specs., so, I do not have any idea about the original resistance, magnet wire diameter, polarity and winding direction on each bobbin.
Now, the owner ask me to rewind it on the original specs.
Can Someone helps me?
Regards!!

[Ruel]

Try looking them up from Dimarzio's website.

[David Schwab]

The DiMarzio website lists the DC resistance as 17.89K. It also uses patent #4501185 which is for having both coils wound with "substantially the same number of turns" but different wire gauges.

So it's hard to say what gauge was used on which coils, and how many turns was used, etc., to get to the final DC resistance. If both coils have the same number of turns of two different gauge wires, each coil will have a different DC resistance reading.

The only example they give in the patent is:

As an example, one of the coils may be wound with 5,400 turns of 42 gauge wire, while the other coil may be wound with the same number of turns of 44 gauge wire (American gauge standard).

The gauges of the wires and the number of turns constituting the coils may be varied, to emphasize different frequencies. By making the number of turns in each coil approximately the same, objectionable hum is avoided. However, the particular number of turns and the gauge sizes selected will depend upon the frequency response desired.

So, your guess is as good as anyone's. Unless you can get a stock pickup to study, I don't see how you would know... unless someone already figured out the formula.

[HCGUITARS]

Dear David, Thanks!!
Great information!
It really clarifies too much to me.
Based on the example I calculate a relation using the following information:
42AWG = 8,4398Ohms/meter (nominal DC at 20C)
44AWG = 5,3594Ohms/meter (nominal DC at 20C)
0,135 meter by turn around the pickup bobbin (over the first layer)

5400 turns x 0,135m x 8,4398 Ohms (44AWG) = 6,15 KOhms
5400 turns x 0,135m x 5,3594 Ohms (42AWG) = 3,91 KOhms

Total DC resistance = 10,06KOhms
10,06KOhms/6,15KOhms = 1,6358 the value to be used as a percentual factor for 44AWG.

Based on Steves Special 17,89 DC we can deduce:

17,89KOhms/1,6358 (Factor) = 10,94KOhms for 44AWG
The remaining of 6,95KOhms for 42 AWG.

Calculating the number of turns:
10,94KOhms/0,135meter/8,4998Ohms meter = 9.534 turns of 44 AWG.
6,95KOhms/0,135 meter/5,3594Ohms meter = 9605 turns of 42 AWG.

To improve it we can found an average value:
9534 + 9605 = 19139 turns/2 = 9569 turns on each bobbin.

Only to comprove:
9569 x 0,135 meter x 8,498 Ohms meter (44AWG) = 10,98KOhms.
9569 x 0,135 meter x 5,3594 Ohms meter (42AWG) = 6,92KOhms
Total = 17,90KOhms.

If I can not found one original unit to measure and confirm the wire diameter, I will make one acc. to the values above as a target and test it.
I will use the values as a start point, I think that will be necessary less turns than I found, so, I will be measuring the DC during the winding process.
Is really difficult to me found DiMarzio products at Brasil at a reasonable cost, and, unfortunately, I do not have how to buy it on ebay, since DiMarzio does not allow the vendors to send it to Brasil!
I do not want to be broken any patent, this is only to rewind my customers Pickup!
I think that will be difficult to put 9570 turns of 42 AWG on one of the bobbins, and, I never used 44AWG wire before, so, it will be a challenge to me.

Thanks Again!!

[Dave Kerr]

Originally Posted by HCGUITARS

I do not want to be broken any patent, this is only to rewind my customers Pickup!

The patent was issued in 1985, so even if a rewind would be an infringement on the patent (which I doubt), you have no worries as the patent owner's exclusive rights have expired.

[David Schwab]

Originally Posted by Dave Kerr

The patent was issued in 1985, so even if a rewind would be an infringement on the patent (which I doubt), you have no worries as the patent owner's exclusive rights have expired.

I've been using this idea ever since I realized that patent was expired.

You can get some really cool tones mixing wire and turns.

[David Schwab]

Originally Posted by HCGUITARS

I think that will be difficult to put 9570 turns of 42 AWG on one of the bobbins, and, I never used 44AWG wire before, so, it will be a challenge to me.

They probably went with 43 and 44, or 44 and 45. They might have also skipped a gauge, like 43 and 45.

44 and 45 aren't so bad to wind. I broke the wire a few times when I was getting the feel for the 45, but I've wound a few humbuckers with it since and it's not bad at all.

[salvarsan]

I ran some numbers.

Criterion 0: the coils have the same number of windings.
Criterion 1: the combined resistances must be ~17900 ohms.
Criterion 2: the wire must fit on the bobbin.

For a 17.9k combined resistance, you can't fit enough AWG 42
on a PAF bobbin in any combination with AWG 43, 44, 44, or 45.

Estimated possibilities are:

1. 6900 winds of #44 and #45
2. 7400 winds of #43 and #45
3. 8300 turns of #43 and #44

The Principle of Maximum Laziness suggests #1.
A desire for less muddy sound suggests #3, but my dodgy coil estimator
says 8300 winds #43 on a PAF is tight, nearly full.

-drh

[Achiles]

i dont know if it?s right but...
http://www.geocities.jp/dgb_studio/index_e.htm

[HCGUITARS]

Thanks all you guys!!
You are really solidary people!
I am inclined to use the 43+44 recipes.

[David Schwab]

Originally Posted by salvarsan

The Principle of Maximum Laziness suggests...

I thought about using the coil-u-lator, but I was being too damn lazy!

Glad you did it.

I figured sooner or later...

[Achiles]

http://www.geocities.jp/dgb_studio/index_e.htm
At Humbucker's Calculated turns 2
There are some # for DP 161

[salvarsan]

Originally Posted by David Schwab

I thought about using the coil-u-lator,

That was for verification.

My thinking went this way:

Same # turns --> same lengths wires = L
Rwire = wire resistance/1000ft.
L x Rwire1 + L x Rwire2 = ~17900 ohms

Solve for L length, solve resistances for wires,
then calculate the turns around a 50mm PAF bobbin.

Afterwards, use the Coil Estimator to fiddle with the fill factors
which are usually higher for skinny wire.

The DGB site lists ~5850 turns of ~#43 and ~#46 (.06mm & .046mm),
mentions resistance and inductance, but does not explain calculations.

I'll amend the previous post to include #46 when I have some time.

-drh