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Magnets & Copper Wire: A Pickup Building Thread
- Thread starter Freekmagnet
- Start date
Reading these posts inspired me to dig through my prototype archive. I unearthed this gem.
It actually sounds better than I remember it sounding. In fact it sounds really similar to the P90-style fat single coil I have installed in my Modelo Uno, but it’s got more of those sparkly highs everyone loves. Decent amount of booty to it. It could use use a little more output, but I figure I could slap a few hundred more turns on this puppy and still have brightness to spare.
Hmmm... ...I used these .02” thick pieces of stainless steel for the side poles... I think it could be built with the same footprint as my fat single coil.
Only problem is, I don’t remember if the magnets are A5 or A8. I’m 85% sure they’re A8.
It actually sounds better than I remember it sounding. In fact it sounds really similar to the P90-style fat single coil I have installed in my Modelo Uno, but it’s got more of those sparkly highs everyone loves. Decent amount of booty to it. It could use use a little more output, but I figure I could slap a few hundred more turns on this puppy and still have brightness to spare.
Hmmm... ...I used these .02” thick pieces of stainless steel for the side poles... I think it could be built with the same footprint as my fat single coil.
Only problem is, I don’t remember if the magnets are A5 or A8. I’m 85% sure they’re A8.
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slowburnaz
Commercial User
Not a sidewinder, but I did just get this to the point of being ready to pot tonight...
Split coil (obviously), meant to fit in the same route as my multicoil pickups.
No idea how it sounds yet. Lol. I need to make some mods to the 5 string that I plan on putting this into before I can find out.
Split coil (obviously), meant to fit in the same route as my multicoil pickups.
No idea how it sounds yet. Lol. I need to make some mods to the 5 string that I plan on putting this into before I can find out.
slowburnaz
Commercial User
As always, very nice engineering and fabrication! You make the rest of us look like amateurs.
From the geometry of the coils and the magnetic field, I'd guess it'll sound in the P-bass pickup class. Generally thick and fuzzy.
slowburnaz
Commercial User
I don't know about that... but thanks!
That's what I'm hoping for.
Looks great again. If you need to balance the coils you can make both coils with 3 pole bobbins, just left one hole empty on one coil. Identical size coils have equal output.
I used to wind very similar split single "buckers" to make pickups with odd numbered poles. I wound identical coils but added a wood spacer at each end before winding so the coil winds centered on the actual magnet poles. It worked well and the outputs of the two coils were equal, but more importantly, cancelled induced hum. That was the point of making them split coil singles, and making the coils identical fulfilled that function well.
The bottom lap steel in the photo has a 7 pole bucker:
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slowburnaz
Commercial User
Yeah, I'm curious to see how the output is on the smaller coil. I was working off of the way Fender did their 5 string P pickups, with asymmetrical coils.
I suppose I could wind it a bit hotter if necessary (maybe this is what Fender does/did?), or do like you're saying. My only worry there was that since I also made the keepers span three strings, and the magnet spans that whole side as well and charges the keeper on that coil, that even with no pole piece, there'd be a small signal being generated by both coils under the A string. Might not be significant enough to truly make much difference, though.
Yeah, when I made a 3 + 2 version my AMB-2 pickup, I went with the same number of turns of the same wire on the two coils. The DC resistance was different between them, but so what? It was a nice balance in level and sound across all the strings, and the hum was thoroughly bucked. I think it's more important to match turns, geometry, and magnetic field than DCR.
slowburnaz
Commercial User
slowburnaz
Commercial User
My understanding has always been that it's the number of turns that count (heh). Or, more specifically, the number of wraps that the magnetic field lines pass through, that determines output.
Yes, it's the turns that count!
Think of it this way: Every time the magnetic field sweeps across a length of wire, it creates a small amount of current in the wire, at very low voltage (microvolts).
Now, if you sweep the field across the side of a coil, it's 6000 little lengths of wire, and they are all connected together in series. The current through the wire is the same, but you now have 6000 times the voltage. The voltages all add up together.
The voltage level of the output signal from the pickup is primarily determined by the strength of the magnetic field, and the number of turns the field passes through. The total length of wire, the wire gauge, and the resulting DCR mean something, but mostly in the shape of the overall EQ curve, not the overall signal level.
Think of it this way: Every time the magnetic field sweeps across a length of wire, it creates a small amount of current in the wire, at very low voltage (microvolts). Now, if you sweep the field across the side of a coil, it's 6000 little lengths of wire, and they are all connected together in series. The current through the wire is the same, but you now have 6000 times the voltage. The voltages all add up together.
The voltage level of the output signal from the pickup is primarily determined by the strength of the magnetic field, and the number of turns the field passes through. The total length of wire, the wire gauge, and the resulting DCR mean something, but mostly in the shape of the overall EQ curve, not the overall signal level.
Agreed Faraday’s Law of Induction says you should have the same turn count if you want the induced voltage due to the strings moving in a field to be the same for each half. The coil with the larger area will pick up more hum as noted by others so the cancellation isn’t perfect. It’s not that bad, but when I make pickups like these in addition to having RWRP halves in any individual pickup (required for humbucking) coils of identical size are RWRP between the two pickups. This way you get much better humcancelling when both pickups are on.
slowburnaz
Commercial User
...and the "family pic" (forgive me if you all are sick of these posts, but who else am I gonna show 'em off to? 
)
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