made a 'bifilar' hb, took some measurements

[dpm]

Hey all!

After messing with tapped coils and switching wire gauge part way through coils I remembered the bifilar discussions here and thought I'd try winding a HB with 2 gauges of wire simultaneously, then connecting the coils in series... just to see what happens. I wound with 42 and 44 AWG simultaneously, 3000 turns/coil, then connected the end of one gauge back to the start of the other so it effectively becomes 6000 turns/coil. I then wired the whole thing as a series HB as usual, took some measurements and had listen. The result wasn't good Lots of capacitance so poor treble, but the low end was surprisingly tight. It sounded much like a tone pot rolled off but with more clarity. I suppose it might have some use for jazz players who roll off their treble, hard to say, and it did sound nice and fluid with gain but definitely a one trick pony. Anyway, here's the measurements I took, which I found interesting. Keep in mind this was a 7 string multiscale humbucker using M3 bolt polepieces and no keeper bar. A5 magnet. I use single sided PCB blanks for baseplates, so a thin layer of copper. Hopefully this is useful for some folks.

DCR - 13.44k

Inductance @ 100Hz - 3.9H
Capacitance @ 1kHz - 12.5nF
Capacitance @ 10kHz - 5.76nF

I'm not sure yet if it was a total waste of time or good educational experience.

[CRU JONES]

Cool Man!
The Inductance seems low. No?

[dpm]

Off the top of my head, yes it does seem low, but then there's no keeper bars so not so much steel in there. On the other hand the capacitance is obscenely high, it's normally in the 100 - 200pF range @ 10kHz (again off the top of my head).

I'll rewind the same pickup in the normal manner with 43awg to get some comparison numbers. Maybe on the weekend depending on time constraints.

Too bad the results were so crap. Winding 2 wires at once handles like a bigger gauge and takes half the normal time

[David Schwab]

Did you try them in parallel?

Or try this; wire the two 42 coils in series, and then the two 44 coils in series. Then wire the whole thing in parallel. You can also try switching between the two. Could be kind of cool.

Seems like you could wire it up to be a two or three trick pony.

I just started making a four coil P bass pickup. Each half is like a humbucker, sort of like the DiMarzio Split P. But I ran the wires from the two pairs of coil out so you can wire it different ways. In series, it's dark, but clear. Then I can do one pair of coils for a bright tone, and then all four in parallel, which is interesting. It's thick yet bright sounding.

[Joe Gwinn]

Capacitance @ 1kHz - 12.5nF
Capacitance @ 10kHz - 5.76nF

How did you measure the capacitance?

[Dave Kerr]

You might want to see how well coupled they are capacitively by using just the start of the 42 and the end of the 44 and see what you get - isn't that Gaglio's approach?

[David Schwab]

You might want to see how well coupled they are capacitively by using just the start of the 42 and the end of the 44 and see what you get - isn't that Gaglio's approach?

Yeah, he doesn't connect the ends of the coils together.

[belwar]

How did you measure the capacitance?

That was exactly my question..

[CRU JONES]

DPM,

I wound a bifilar with the intention of connecting the coils in series as well. I used a spool of 43PE with a spool of 43SPN. Both single build. I set them for 3500 winds... Total of 7000. I tested it and came up with high capacitance as well. Total inductance for the HB was more than 8H. The bifilar coils had leads out the top and bottom increasing the likely hood that I would wire a coil out of phase which I did, of course; resulting in lower inductance readings. I'll try to dig that coil up and get measurements.

Ethan

[dpm]

cool questions. I'll try to get a few other readings from the thing before I rewind it... weekend stuff for sure

[soundmasterg]

You could purposely design a pickup to be overly bright and then wind it this way to tame some of that?

Greg