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About Brickster86

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  1. flipping the bobbin changes the winding direction of the coil. The induced signal current from the 60 Hz source is now 180 degrees out of phase with the signal current from the other pickup, therefore canceling out the 60 Hz noise. Flipping the magnets is required to get the string signal back in phase with the other pickup.
  2. Thanks to animalfarm for the great exploded P-90 picture. I edited this and added a few tips on rotation/flipping of the parts that I describe. Hopefully this makes it more clear. Basically, you rotate the bobbin so that the top is now the bottom, and vice versa (axis of rotation is the around where the cable comes in on a short side.) Think of just grabbing the cable, and turning the bobbin upside down. Each magnet gets rotated like a propeller so that the poles are swapped (note that the poles are on the long sides, not the short sides like you would think). Don't flip them, just make the inside now the outside, and vice versa.
  3. The other mod is quite messy! The mod I did is way more straightforward (step 2 is the same what I did). The only similarity is the removal of the magnets, but not replacing per se. Fortunately, the P-90 covers just come right off and the only tool required is a Phillips screwdriver and perhaps a small blade screwdriver to pry out the magnets.
  4. The hum cancelling is only in the center position; it actually still sounds really good. Remember you still have 2 "pure" P-90 modes by selecting the rhythm or treble positions. I think this is a better alternative than replacing the P-90s with humbucking replacements. If you can't stand the quiet, you can always change it back! :)
  5. I justed added a new thread on an easy hum-bucking mod for the '56 GT (Easy P-90...). I just did mine last night. I think the P-90's are what make it cool, but having a humbucking position on the pup selector makes it bearable.
  6. Forgive me if this has been answered 1000 times, but I bought a '56 Goldtop with P-90's this summer. I love the guitar in every way, except that the 60 Hz hum is excessive (I am unlucky to have power lines close enough to my house that seem to get picked up quite well by the pups). Anyway, after searching for all sorts of fixes on the web, it seems that converting one of the pups to a reverse wired, reverse polarity was the answer. However, every post talked about swapping wires (i.e. cutting and/or resoldering) on the pickups. I was not interested in that so I figured there had to be a better way. There is, and it's easy. I did it last night, but unfortunately, I didn't take pictures. I think you'll be able to follow it anyway. It took me about 15 minutes (minues the re-do because I had the magnets wrong; see Tip). 1. Take off the strings by any method you want (I just loostened them and removed the tailpiece from the bolts). Remove the cover screws on the bridge pickup (doesn't matter which, but the bridge seemed to have a bit more wire slack. If not, open up the vol/tone cover and carefully snip a cable tie to free up the cables) 2. Carefully lift the pickup out of the hole. It should be waxed together, so nothing should fall out. Take a Sharpie and mark the outside edge of the two magents above the bottom plate. Also mark the top of the bobbin. This is very important as magnet polarity is key. 3. Unsrew the pole pieces (six screws on top) and the two screws holding the bottom plate to the pole plate (thin metal strip that sits between the magnets). Carefully take out the magnets. Since everything is waxed together, gently pry apart with a small screwdriver. 4. Flip the bobbin over and arrange the plate and pole plate between the bobbin bottom (used to be the top) and the plate. Put the magnets back in between the bobbin and the bottom plate, making sure that the edge that you marked is now on the inside against the pole plate. If you have a compass handy, make sure that the pickups now have different magentic polarity (one should attract N, the other S as you hold the compass perpendicular to the pup face). 5. Re-attach all the screws and re-install the pup and cover. Congratulations, you now have humbucking P-90 axe when playing in the center position. Tip: If the center position is hum-free, but sounds thin and nasaly, the magnets are not installed correctly. Why does this work? Because the 60 Hz hum only interacts with the coils, so reversing one causes a phase inversion that cancels out the hum. The strings interact with the entire coil/magnet system, so reversing the magnets reverses the phase once again, resulting in a zero phase reversal, just like the original. Neat huh?
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