Hum Size P90 and terrible hum

[madialex]

Hi Guys, I have taken 2 humbucker bobbins, glued them together and wound 1 large coil around the outer edges of it so with a cover it looks like a humbucker with the adjustable poles and all. On the inside it has a regular humbucker baseplate, slugs in one side, screws in the other, I have 2 skinny ceramic mags running against the outside of the slugs and screws, 2 magnets total both north facing the slugs and screws. Sounds really good, crisp and clean and does a really good Thin Lizzy Jail break tone with distortion. Now the problem, the dam things buzzes like mad, even on the clean setting without any distorto. I have tried isolating the ground from the base plate, running it from the base plate, lifted the ground, nothing helps. Will this thing ever get quiet or should I just give up and trash the whole dam idea.

PS- I am using the ceramics that come on the bottom of cheap strat pickups, the 2 skinny ones on each side of the slugs and I am using the braided style 2 conductor wire. Any help is appreciated.

[David Schwab]

Sounds like an interesting idea!

I can only think that the large size of the coil is contributing to the hum.... the bigger the coil, the more hum you get.

Do you have all the metal parts grounded? The braided shield should be soldered to the base plate, and the pole pieces should be grounded as well.

Just as a test, try wrapping the whole thing in aluminum foil, grounded to the base plate, and see if that helps... this would at least give you an idea if it's the coil picking up hum.

I have a bunch of those strat pickups which I have been harvesting the ceramic magnets from for trying out pickup ideas. They are pretty good magnets.

[Possum]

not a new idea

I did the same thing, the drawback is you can't get alot of wire on it in 42, plus you have to drill a second set of pole holes, third its noisy. Its one project I shelved. You could actually get better results winding both bobbins and NOT making them humbucking and using a single ceramic magnet. I had a whole box load of magnets made for that project, luckily I found other uses for them. You can't buy that size from anyone unless you have them made. REally to make it work you would have to make your own single bobbin, but then you are stuck with the holes in the baseplate and the cover which are unmoveable. Anyway, I got better tone out of a P90 in a bucker housing and was able to use enough 42 wire on a matched balanced set......

[madialex]

Hi Possum

I knew you had probably done this before and hoped you would see the post and chime in. When you say wind both coils and not wire them humbucking, how do you wire them? Paralell? This thing is not only noisey but I'm finding it hard to get a lot of usable tone, its way too dark so I loosen way back on the tension to get it brighter and I lose output, tighten it up and get output back but too darn dark. I've used slow scatter, med and fast, tight med and loose tension etc...Just cant nail this thing down like I want, i'm getting close but no cigar just yet. The best I think I have come up with yet is med tension, and 2 or 3 different scatter patterns on the same wind. Please elaborate on the wiring of the 2 coils. I have done this before with the paralell wiring and got some good results but never persued it further. Thanks.

[David Schwab]

When you say wind both coils and not wire them humbucking, how do you wire them? Paralell?

You can have a humbucker wired in series or parallel. The thing that makes it a humbucker is having reverse polarity magnet poles on each coil, and then wiring the coils "out-of-phase" (actually it's reverse polarity... phase is a term used for shifting a waveform in time). The reverse magnet poles makes the signal in phase when the two coils are summed together.

I suppose if you wire both coils in phase it wouldn't be a humbucker, but then they will sound out of phase because of the magnet.

If both coils had the same magnet polarity, and were wired with the same electrical polarity, you would have two single coils in series, with no hum cancelation.

I'm suspecting part of the problem with the faux P-90 using two HB bobbins is you are using two sets of poles and each is opposite magnetic polarity (i.e., one is N and the other S). You need to have them both the same.

[Possum]

easy fix

Oh, noticed you used slugs, change that to two screw pole bobbins and you'll get useable tone, but then you will have to drill an extra set of holes in the cover. It'll still be noisy....

[madialex]

Oh, noticed you used slugs, change that to two screw pole bobbins and you'll get useable tone, but then you will have to drill an extra set of holes in the cover. It'll still be noisy....

Yeah, I thought about the double screw poles but the darn noise is the killer for me. I actually wound one the other night that really sounds very nice, very nice clean, bloom if thats such a word, string to string balance, note definition etc... Dirty it really rocks with a sort of old school Paf kinda tone to it. I really liked it but the darn noise, AARRRRRRGHHH. I tried everything I could to quieten the thing, grounded the poles and slugs to the frame?? used the copper tape stuff in every conceivable way, to no avail. I guess it is just too much metal in a single coil to not be noisey not to mention the coil being almost twice as wide as a normal P90. Oh well, I guess it's back to using a regular cut down P90 bobbin and drilling the baseplate out then making a top for the thing out of pickgaurd material etc..... What a pain in the censored!!

[Possum]

yep

yeah now you know why I bailed on that one. Cutting down a P90, well I guess that works, you should really make your own bobbins though for that one, its what I do, pain in the ass but you can get more wire on it I think, still noisy, but pretty close to P90 tone. Handmaking them you can also get the bobbin depth deeper too add more wire, with 42 you can't get much on a real P90 bobbin in a cramped bucker space, too bright not enough power. Took me alot of tests to find what worked in that one, too deep a coil and the magnets lose power due to barely grabbing the pole screws, a very fine balance there, alot of tests to find what worked. My website has these with sound clips, they are called KayBars, and those are the Modern version I make, pretty close to P90 tone but real P90s still are tits.....

[SK66]

Yeah, I thought about the double screw poles but the darn noise is the killer for me. I actually wound one the other night that really sounds very nice, very nice clean, bloom if thats such a word, string to string balance, note definition etc... Dirty it really rocks with a sort of old school Paf kinda tone to it. I really liked it but the darn noise, AARRRRRRGHHH. I tried everything I could to quieten the thing, grounded the poles and slugs to the frame?? used the copper tape stuff in every conceivable way, to no avail. I guess it is just too much metal in a single coil to not be noisey not to mention the coil being almost twice as wide as a normal P90. Oh well, I guess it's back to using a regular cut down P90 bobbin and drilling the baseplate out then making a top for the thing out of pickgaurd material etc..... What a pain in the censored!!

It's all of the air gap in the middle of the coil with weak/no field, basicly "dead space" for collecting noise signal. Maybe a steel bar between the pole sets, touching both and grounded might help(really don't know...but shouldn't hurt with ceramics) The bar WILL affect the aperature and loading. Maybe a 3rd ceramic mounted in the hollow between the coils with opposite polarity up...(Will also affect the aperature)