Machine vs handmade winding, some tests with interesting results please take a look.

[FunkyKikuchiyo]

1) To compare the sound of these two coils makes no sense, will sound almost identical.

Maybe I'm missing something but if it makes no audible difference, what is the point? Isn't the initial controversy whether or not "handwound" had a different sound? Or, did you start the comparison in order to prove this very point?

It does seem like there are too many variables. It seems it would have been use to use the same machine, and simply replace the mechanical traverse with someone's hand instead of using an entirely different set up. Now you have virtually everything in the set up as a potential variable.

[big_teee]

New flame to an Old Fire!
As long as there are bootique pickups, there will always be both machine, and Hand Wound, So what's the point.
In the Audio World, I'm all about what they sound like.
They both can sound great!
Terry

[SonnyW]

New flame to an Old Fire!
As long as there are bootique pickups, there will always be both machine, and Hand Wound, So what's the point.
In the Audio World, I'm all about what they sound like.
They both can sound great!
Terry

To add to Terry's point, even if they sound the same there will always be some customers that prefer or even insist on handwound or vice-versa. Just look in the forums to verify that. And I've unwound a couple of the custom shop pickups with AY initials that were so nicely done that they almost looked machine wound, though I am sure they were actually handwound.

[Possum]

------

You can't really draw any conclusions from just this one test. With your CNC coil how many turns per layer did you use? That is super important to know. I've never been able to find any rational relationship with turns per layer vs. resonant peak, you would think fewer turns per layer would make the pickup brighter, but fewer turns per layer tend to build the coil diameter size larger and that pulls the rez peak down. So, its complicated and definitely not linear. Also a tigher wind will give more capacitance and pull the rez peak down, tension is important.

The hand wound coil has more random cross overs in the wire layers and this rounds of the resonant peak instead of a sharp peak, that machine wound coils can have sometimes. Its almost impossible to come up with any rational equations that work all the time, you just have to wind an awful lot of pickups and try everything you can think of and see how it sound to your ears. Eventually out of chaos you find something that sounds good and stick with it. Resonant peak isn't the only thing you look at either, how do the mids settle out? They are real hard to see on a frequency analysis as small changes can't be seen too well but can be heard. Don't go by instruments alone, but do as many experiments as you can think of, in the end it will make you crazy but you gain experience and eventually make better choices and find your own recipes. I did tons of these experiments and have my own ideas that work, and sort of rational explanations why they work. Thinking about this stuff makes my head hurt

[the great waldo]

I had a customer the other day to whom I recommended a set of my strat pickups. He asked me "why should I buy a set of your pickups" to which I replied "they sound good" I let him borrow an old squier strat with my pickups in and he came back a week later and was amazed with the sound. He asked me why the sound was so good and I told him that I made them as well as I could with what I thought were the right materials. Another happy customer. It would be nice if we could have a really good way of measuring the parameters of pickups to try and get some kind of consistency when making them. I´ve got the bits for elepros winder (still have´nt found time to put it together, sorry elepro!) and am looking forward to using it to get some reliable way of winding. Hand winding is all over the place and unless your doing it it all day long I would imagine it´s highly variable. Just a thought.

Andrew

To add to Terry's point, even if they sound the same there will always be some customers that prefer or even insist on handwound or vice-versa. Just look in the forums to verify that. And I've unwound a couple of the custom shop pickups with AY initials that were so nicely done that they almost looked machine wound, though I am sure they were actually handwound.

[WolfeMacleod]

For 42 AWG it's best to cut with scissors.PCB soldering uses special liquid fluxes that you can see on the attched screenshot.
For drawoffs from the coil we use silver-plated wire in teflon insulation. If you ever hold this kind of wire in your hands,
then you have to understand what we are talking about. The winding wire itself is not oxidized because it is isolated, thats why it is soldered with a conventional rosin.

My post regarding soldering was pointing out that you were "painting" solder onto the pigtail lead instead of applying solder directly to the joint while soldering. You applied solder to the tip, then "painted" it. Not a good practice, so far as I remember from my year long electronics course from the late 80's.
After wrapping the coil wire around the pigtail, soldering the lead is basically the same as tinning the wire. When tinning the wire, you should apply directly to the wire while heating it.

[FunkyKikuchiyo]

My post regarding soldering was pointing out that you were "painting" solder onto the pigtail lead instead of applying solder directly to the joint while soldering. You applied solder to the tip, then "painted" it. Not a good practice, so far as I remember from my year long electronics course from the late 80's.
After wrapping the coil wire around the pigtail, soldering the lead is basically the same as tinning the wire. When tinning the wire, you should apply directly to the wire while heating it.

That was a good link, regardless of how relevant it is in this thread. If only you'd sent that to me ten years ago, you'd have saved me a lot of trial and error! It is basically how I solder now, but a lot of bad habits are pointed out in that video.

[Mike Sulzer]

As for measurement techniques using a probe Rin=10 mOm - this is the only true test method for measuring the resonant peak. Even better to use AD 624 that would minimize the drawdown in the measurement at the beginning of the spectrum, although this part of the curve a little informative to pickup sound modeling on the spectrum analyzer.
Using Rin=1 mOm is erroneously because this gives a reduction of the spectrum акщь 1 ещ 2.5 kHz that would not be a true value.

This shift of 2.5 KHz very much conflicts with my experience for a change in load of 10 meg to 1 meg. Just for fun I calculated the effect using a 1.8 H coil with 160 pf across it and a series resistance of 4 K. (Note that these values are more like a coil with cores, rather than air core. The resonance is just under 9400 Hz.)

The difference with 1 meg and 10 meg is about 20 Hz, not 2.5 KHz.

However, in reading back over your posts and looking again at the figures, I am confused. You write this: "Even better to use AD 624 that would minimize the drawdown in the measurement at the beginning of the spectrum." By beginning of the spectrum, if you mean low frequencies, that makes no sense. The impedance of the pickup is just a few K at low frequencies.

[marku52]

I would still be very leery of using a 10X probe to test for high accuracy frequency response in the audio band. My first job out of EE school was designing those silly things for Tektronix, and I can tell you every way they can go wrong, or steer you wrong. Particularly the capacitors (actual and stray) can give great grief. We would test our new products in a humidity chamber, and if there was any, and I mean *any* ionic contaminants on the circuit board inside the comp box, the 1 kHz square wave response would look like a fun house mirror, with wild 100's of percents overshoots and rings. And of course, the corresponding frequency response in the audio band would be all over the map. What kind of ionic contaminant? Oh, things like solder flux, human sweat, bad raw pcb material (they hadn't washed the fiberglas adequately), any of these would completely ruin the AC accuracy of the probe. One time, after recieving a bad batch of pcbs, we went to inspect the fab and found that the last person on the line who stuffed the finished boards into antistat bags was eating Doritos (salt!!) at her station. Boy was the QA guy embarassed.

And capacitor component quality mattered too. Any dialectric absorption in the capacitors used would create similar problems, only, without requiring the humidity.

Bottom line? I would never use a 10X probe for audio flatness tests unless the measurement can't be made without it due to loading effects on the source. And that is certainly not true in this case. The 1Mohm scope input R is plenty high enough.

[Mike Sulzer]

Bottom line? I would never use a 10X probe for audio flatness tests unless the measurement can't be made without it due to loading effects on the source. And that is certainly not true in this case. The 1Mohm scope input R is plenty high enough.

A couple of points:

1. If 1 M were not high enough, we can get an extremely high input impedance by using any op amp as a follower. No resistor is needed at the op amp input since the coil provides the path for the dc bias current to ground.

2. We should say why 1 M is enough. That is, why did I compute 20 Hz above rather than a larger number. The key here is to understand that the loading is a second order effect rather than the first order effect that MrCandy is telling us that it is.

How does this work? First, think of a perfect L in parallel with a C. It is easiest to think of admittances, the inverse of impedance. Admittances in parallel add, and the L and C have admittances at resonance that are equal in amplitude and opposite in sign. So they add to zero. At any other frequency they do not add to zero. Now put a resistor in parallel; this adds an admittance of 1/R at each frequency. Obviously the original resonance frequency has the minimum magnitude, and so the measured resonant frequency does not change.

Now put some resistance in series with the L. The phase angle of the L+R combination never reaches 90 degrees, and so there is never a perfect resonance. Now we can see that a resistor in parallel might affect the minimum in the admittance (peak in impedance). How much, I do not know; you have to compute it to see. It is a second order effect because two things have to happen to get an effect: 1. a less than infinite parallel resistor, and 2. a greater than zero series resistor.

[Joe Gwinn]

Many 1 Megohm scope inputs usually have a significant input capacitance. What make and model of scope is being used? The specifications should tell the input capacitance.

Likewise, cables from test setup to scope input may have their own little contribution.

[MrCandy]

By beginning of the spectrum, if you mean low frequencies, that makes no sense. The impedance of the pickup is just a few K at low frequencies.

although this part of the curve a little informative to pickup sound modeling on the spectrum analyzer.

With respect
MrCandy

[MrCandy]

Ok, our chief engineer at the request of the workers compete the third measure method by the active probe which uses MOSFET Cin=2.1 pF. Rin reaches monstrous quantities. Pickup connects directly to the Gate, also at probe output repeater on the operational amplifier is used. Obtained data is similar with 2 listed earlier. We also present measurements using a cable and analyzer Rin=1 mOm(to eliminate the effects of virus factors we used driver coil), also at the request of the workers, difference compare to 3 measuring methods listed is really very huge, on the example of STRAT 57/62 you can see that the difference is near 2.20 kHz.
If we analyze carefully the information provided we can derive a "Theory of Relativity"
The essence is:
Formvar is a myth.
P.E. is a myth and marketing.
With the help of Pole winding wire(specially selected for pickup-making with extreme thin isolation) changing variables you can wind the coil with any desired characteristics RP and Q, and accurate measurements are needed to model, not for the determination of the fact that what you are doing.
With Formvar for example you cant wound what can be wound with Pole(with thin isolation) and P.E.

[MrCandy]

one more)

[Mike Sulzer]

With respect
MrCandy

Uh huh. You are the one who said using the ultra high impedance would make a difference at the low frequencies, right? Now you are saying you said that it does not?

with even more respect,

Mike Sulzer