Lollar book, time to republish!!!!

[Sweetfinger]

It also discusses small details about manipulating wire that you wont figure out for a long time- lots of little details that might seem unimportant or insignificant at the time you read them

That's the stuff I'm looking for...I'm perfectly capable of making a winder that will fullfill all my fiendish plans, I just don't want to spend the rest of my life discovering stuff when I could browse a couple pages of info- Its like trying to bake a cake without knowing that the flour needs to be sifted and the pan needs to be greased!

[ken]

I'm not proud...

I tried to wind pickups long ago with indifferent results, but it wasn't till I bought Jason's book that I figured some of it out.

Thank you Jason L!

Ken
ohmwiz@yahoo.com

[Possum]

driving test coils

Uh oh, driving a single coil with only 3 poles with an oblong coil? That sounds bad. If we're going to use a drive coil at all I'm sticking with what I got, a really low impedance humbucker bobbin, it fits over any single coil, or blade pickup, fully engages the pickup its driving, engages all the poles in the test pickup, works on humbuckers if you tilt it up and place between the two coils. An oblong coil is going to hit some poles real good and miss some others because of its shape, and isn't going to work well with a bucker at all. At least Lemme had a good idea there, but he only used it IN a guitar which I don't like. then there's the issue of 500K pots and 250K pots, how does that play into this? Why are we even trying to simulate an amp load to begin with? The idea to me is just to get a consistent , stable measurement platform that will show small differenences in frequency response accurately in a plot or digital readouts across a spectrum of frequencies (would actually prefer that to a chart myself). Guitar players don't know diddley about resonant peaks anyway, all I'm looking for is a constant measurement base as a platform to judge pickups against eachother, not how they are going to work in a simulated amp load. Once you have some kind of measurement base, you then use your ears as to how they affect whatever your favorite type of amps are and then can make judgements on comparisons.

What I think would be the most valuable of all would be the simple drive coil, some really simple way to sweep the coil then pick a bunch of frequencies you want to see where the output is affecting each and maybe a chart of the full spectrum. It doesn't have to be more complicated than that, unless you want to get into different harmonics and I think that would be hard to comprehend whats going on with that kind of thing, maybe. My two cents....

[David Schwab]

then there's the issue of 500K pots and 250K pots, how does that play into this? Why are we even trying to simulate an amp load to begin with?

The pots and other loads affect the response of the pickup. You can hear this if you take a high impedance pickup, like a humbucker, and run it into a buffer amp. Buffered, the tone has more highs and lows, and the resonant peak of the pickup is higher. This is because the pickup is being isolated from the impedance loads of the pots, cable, amp, etc.

Loading the pickup will lower the resonant peak, and of course right after the peak the response curve drops off rapidly. This is why 250k pots sound warmer than 500k or 1M.

If you want an accurate picture of the response of the pickup as it would be in the guitar, you need to simulate these loads.

This is not to say doing tests without the load are meaningless, but the "real world" response will be different... unless you are making an active pickup and have it in the circuit you are going to use.

[DrStrangelove]

Uh oh, driving a single coil with only 3 poles with an oblong coil? That sounds bad.

It's no worse than driving a humbucker at half strength (or less) because you must turn the drive coil on its side.

Those gaussmeters will measure AC gauss, too, and can be used to calibrate the drive coils. Once you know the drive coil output, then its size and shape are less important.

...but nobody has calibrated the drive coil, have they?

Easy. Putcher hall effect sensor in there and measure the AC voltage with a cheap multimeter. Expensive gear not needed.

If we're going to use a drive coil at all I'm sticking with what I got, a really low impedance humbucker bobbin,

How low is it? Meselfs, I'd use a speaker coil as a starting point.

it fits over any single coil, or blade pickup, fully engages the pickup its driving, engages all the poles in the test pickup, works on humbuckers if you tilt it up and place between the two coils.

Why not wind a drive coil that does the same for a PAF style pup?

An oblong coil is going to hit some poles real good and miss some others because of its shape, and isn't going to work well with a bucker at all. At least Lemme had a good idea there, but he only used it IN a guitar which I don't like. then there's the issue of 500K pots and 250K pots, how does that play into this? Why are we even trying to simulate an amp load to begin with?

We are not simulating only an amp load. The amp input stage presents enough of a load to change things more than 10%. I ran the numbers.

The idea to me is just to get a consistent , stable measurement platform that will show small differenences in frequency response accurately in a plot or digital readouts across a spectrum of frequencies (would actually prefer that to a chart myself).

...like, from a dummy load.

Guitar players don't know diddley about resonant peaks anyway, all I'm looking for is a constant measurement base as a platform to judge pickups against each other, not how they are going to work in a simulated amp load.

That's an oversimplification of what I suggested.

The dummy load's purpose is to let you test an uninstalled pickup under conditions similar to actual use, only more easily. A dummy load must account for the volume + tone controls, the cable, and the amp front end. If you build a stomp box or 6, you get a feel for these things.

Anything less and you'd complain that it wasn't "real world" enough. (probably a good place to put a "smiley")

Once you have some kind of measurement base, you then use your ears as to how they affect whatever your favorite type of amps are and then can make judgements on comparisons.

With that same measurement base, you'll be more immune to when your ears start to fool you because they are tired.

What I think would be the most valuable of all would be the simple drive coil, some really simple way to sweep the coil then pick a bunch of frequencies you want to see where the output is affecting each and maybe a chart of the full spectrum.

We can have it simple or we can have it realistic.

Adding in the amp load is realistic, easy, and not even a big deal -- the dummy load reduces to 2 resistors, 2 caps, 2 pairs of clip leads, and a 2x2" square of perf board.

-drh

[Possum]

still with ya

OK, I'm still with ya so far. My dummy coil is wound with 36 gauge wire 5.6K or so. Joe recommended highly keeping the drive coil at real low winds/impedance or it will screw up the results. A speaker coil I think will have its own effect on the frequency response than what I made. I think Lemme mentions that also. That article has fallen off the forum links so here it is again:
http://www.buildyourguitar.com/resources/lemme/
I probably should reread it again, I get different things from it every time I do.

So, ok, have you built this simulated load yet and done any experiments with it yet? I don't have much time to rig this stuff up, and for me it would really be helpful to have digital pix of how to wire this thing, I'm not an amp builder and not great at building stuff from schematics but I can follow a simple, wire this to that diagram or photo.

As for calibrating the drive coil, well with Fuzzmeasure the software only has a static volume level it uses so the output from the card is always the same. FuzzMeasure kinda falls apart in getting specific numberical readings at certain frequencies, it does make a pretty looking chart and does give one an idea of whats going on.