Problem with consistency

[Kindly Killer]

I only make pickups for myself and sometimes it's years in between tinkering sessions. I prefer to make my own because it's the only way I can assure myself I've done everything I can to get the sound I want.

I have a couple of strat type guitars for which I'm currently making pickups. One thing I'm noticing and getting really frustrated about is inconsistency between pickups, specifically a symptom that seems to indicate shorts in the coil?

E.g. I will wind a strat pickup with automatic traverse, same wire, same everything, and the one with 8000 turns will come out about like I expect - in the neighborhood in terms of sound, H, and DCR. Then I will make another with 8200 turns (want more meat) and it will have LOWER H and DCR, which I take it means there are shorts? I try it anyway in my test guitar and it does sound thin and wrong.

I have noticed slightly better consistency using electrical tape on the mags instead of teflon tape, but I don't know what else to address. Even hand winding I get similar problems.

What can I look at to track down this problem? I have a tension gauge but I'm fuzzy on how to use it and I have no idea what number I would look for anyway.

HELP!

[Joe Gwinn]

I have a couple of strat type guitars for which I'm currently making pickups. One thing I'm noticing and getting really frustrated about is inconsistency between pickups, specifically a symptom that seems to indicate shorts in the coil?

E.g. I will wind a strat pickup with automatic traverse, same wire, same everything, and the one with 8000 turns will come out about like I expect - in the neighborhood in terms of sound, H, and DCR. Then I will make another with 8200 turns (want more meat) and it will have LOWER H and DCR, which I take it means there are shorts? I try it anyway in my test guitar and it does sound thin and wrong.

That does sound like a short. One can tell for sure with an Extech LCR meter - a short will also show up as a large AC resistance.

I have noticed slightly better consistency using electrical tape on the mags instead of teflon tape, but I don't know what else to address. Even hand winding I get similar problems.

The problem is that both teflon and electrical tape are too soft, and the wires will swim right through. Better to use paper tape, or polyimide tape.

What can I look at to track down this problem?

I would unwind a bad coil by hand under a bright light, and see what's going on.

I have a tension gauge but I'm fuzzy on how to use it and I have no idea what number I would look for anyway.

Tension gauge won't help unless you're breaking wire. The max allowed winding tension is defined by the wire maker, and appears in wire tables.

[big_teee]

Have you tried different wires?
For Strat SCs I like Heavy insulation, either HFV, or HPN.
For Taping the coils I have had good success with waxed Floral tape.
I get it in White and Dark brown (it looks black) at Michael's Craft store.
T

[Kindly Killer]

Thanks for all responses.

Could I get some specifics on tape: does plain old masking tape qualify as paper tape? How about a brand and model, or even a link? I remember the first few pickups I wound I had some old school cloth friction tape type stuff - is that what we are talking about?

Terry, I looked at Michaels and there are a great many types of floral tape - which one do you get?

If I get Kapton Tape, should I get narrower and make a couple wraps to cover the mags, or get it bigger and cut it to height somehow?


Here is a normal pickup with readings that seem about right. It is 8000 turns of 42 heavy, hand wound


This one has the problem I mentioned. It has 8200 turns of the same wire.


Is that a large number for ACR? It is higher than expected, especially relative to the H.

Also I'm a little slow to understand about tension: does that mean I can rule out excessive tension as a cause of this problem? Or does that mean that the answer lies in data from the wire mfgr., plus equipment I don't have?

BTW I have used three different wires and it happens with all. I just ran out of Elektrisola 42 Heavy Formvar. I also have two big spools of Essex Soderon 42 single that I'm stuck with, so I need to make it work with this wire.

When I get as far as solving this problem for hand winding, I want to consider what contributes to shorts in my traverse mechanism. What is a really reliable guide for a traverse - i.e. specifically what should I feed the wire through? Right now it is just a piece of hard plastic that came with a small hole in it - I don't even know the material. Is there something I can get at the hardware store to glue into that hole that is really easy on the wire?

[big_teee]

I didn't see the tapes i use from Michaels.
My wife picks it up for me in the store.
I use the .5 inch diameter.
I'm thinking a fairly good sized roll is 4-5 Dollars.
You can stretch it some so it fits a SC without having to cut it with scissors.
Lots of guys use the Kapton Tape, I'm sure it works fine also.
The wire I prefer for Strat SCs is the HPN.
Magnet Wire, Enameled Copper Wire, 42 AWG Heavy Build, 0.0029" Diameter, Natural : Magnet Wire
You can get it from a few different places, but I got mine here from Remington.
T

[kayakerca]

Here is a normal pickup with readings that seem about right. It is 8000 turns of 42 heavy, hand wound
[ATTACH=CONFIG]24634[/ATTACH]

This one has the problem I mentioned. It has 8200 turns of the same wire.
[ATTACH=CONFIG]24635[/ATTACH]


BTW I have used three different wires and it happens with all. I just ran out of Elektrisola 42 Heavy Formvar. I also have two big spools of Essex Soderon 42 single that I'm stuck with, so I need to make it work with this wire.

When I get as far as solving this problem for hand winding, I want to consider what contributes to shorts in my traverse mechanism. What is a really reliable guide for a traverse - i.e. specifically what should I feed the wire through? Right now it is just a piece of hard plastic that came with a small hole in it - I don't even know the material. Is there something I can get at the hardware store to glue into that hole that is really easy on the wire?

The 2.4 H in the first picture would appear to be a reasonable value compared with some of my winds in the 8,000 turn area, but the 1.7 H is way low for 8,200 even before the magnets are charged. I find the a change of ~ .10 from pre-charge to post-charge reading. That second bobbin looks to have a lot of space left to take more wire under the flange. Are you certain your counter is doing you justice? If somehow there is a lot less wire, that could explain the the difference. Also, are your finished winds all the same shape? A centre bulge wind will use more wire than a flat wind given the same number of turns which, everything else being equal, would yield lower inductance on the flat shaped wind.

I have used tension from 25 grams to 35 grams and not noticed any measurable difference in output, either DCR or Henries.

I also found that with my mechanical winder (2 sewing machine motors, one running the winder and the other the fan oscillator) the speed of the AC sewing machine motors varies significantly throughout the course of a wind (based on the rpm as I measured it with a digital tach) on both winder and traverser. This would equate to more varied tpl, but I doubt that would effect the output to any measurable degree. I did get more varied DCR and inductance readings on my mechanical traverse winder than I do now on my CNC winder, but never anywhere near the variance in your example above. Everything else being equal, my (uninformed newbish) guess is that there is less or more wire being laid down that you believe for a variance that significant.

[Kindly Killer]

Terry, Excellent info - thanks. I just ordered a big spool of that wire from Remington via eBay.

Any chance you could take a pic of your roll of tape so I could go find it by sight in a Michael's store? I am really desperate to get this solved and move on.

[big_teee]

I have a new package of the floral tape.
It is "Floral Stem Wrap Tape".
The Barcode number on the back is:
0 93432 60039 9
Is a 1/2 inch x 60 ft roll.
T

[Kindly Killer]

SWEET - on my way out the door. THANKS!

[copperheadroads]

I buy my floral tape from walmart ,it's in the crafts\fake flower craP section .its Green

[David Schwab]

I use masking tape.

[big_teee]

I buy my floral tape from walmart ,it's in the crafts\fake flower craP section .its Green

Not to nitpick, but I like that at Michaels, because it Stretches easily.
The green my wife had from walmart was brittle and no stretch, and broke easily.
So I have stuck with the Michaels, and the dark color.
Whatever works.
T

[jason lollar]

I can think of a few things right off the bat- one was already mentioned- a counter not performing correctly and the other happens usually if you are winding a pre magnetized fender bobbin. You can get a very small metal chip on one of the end poles and it can be over or under the tape- as tension builds up over a thousand plus turns the metal chip cuts through the inner wires. It could be a batch of bad wire too, i have seen that many times. Imagine if you didnt have an inductance meter ---

[Rick Turner]

Hmmm...

I'm winding directly on electrical tape wound ceramic magnets, and I have no trouble at all hitting...worst case...plus or minus 2% DCR on 8,500 turns of 44 ga. coil after coil after coil. I then match 'em closer for kicks when putting humbuckers together.

If you're not shorting turns, and if you're winding at consistent speed with consistent tension, and your counter is working properly, I don't see what the problem is. If you're cutting through insulation and winding by hand and tensioning by hand, well, good luck, cause you'll never get "there" that way. The value of "hand winding" is an utter myth. I do it sometimes with prototypes; I do it with weird wire (Litz), but it's for the birds for production. I don't see how folks can be proud of totally random and inconsistent results over which they have no control. Not even acoustic instrument builders go for that kind of randomness in outcome.

[Kindly Killer]

Okay I got my new wire yesterday and made 3 strat pickups in a row with 7800 turns each and they all came out with the same specs (within a small range). The tape Terry told me about is definitely a huge help; it is very easy to get a good wrap that curves around to the flats for foolproof coverage. I'm thinking about buying a lifetime supply so that that problem stays permanently solved. It's hard for me to imagine making more than 100 strat pickups in the remainder of my years, so that is doable.

I tried several more, trying to get a particular sound out of a guitar using my bucket of rejects, where I just cut off the old coil, clean it up, tape it, and rewind. The ones that had problems all had oddities with the flats - flanging at the ends, warping, etc. I think between the tape and warping, that covers the problems I was having. The more I look at my mistakes and think about it, I think all my bad pickups were shorting against the magnets.

I think my problem with electrical tape is that I'm not adequately precise with it. My bobbins aren't super precise, - just a rough wooden jig for gluing them up - and I was just cutting electrical tape in half lengthwise with scissors. I would wrap it around the edges and make two laps - top and bottom - and that was it. I think my technique was not adequate for the task.

Hand winding: One idea I had about the problem I was having was that I was stripping off insulation on my traverse guide. I was just hand winding to try to isolate the problem. Also I am just building my own instrument for my own use - so once I get one acceptable pickup for each position I'm done and all the spools and the winder go back on the shelf, possibly for years. I think I'm satisfied now that using Terry's floral tape and working with sturdy, true bobbins will solve the problems I was having, so I can proceed with auto traverse.

Thanks everyone for all help!

Michael