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previous: ryan hi. i really dig the sound of p90's... -- 10/21/1997 12:12 PM View Thread

Re: noisy p90

10/22/1997 1:33 AM
Steve Ahola
Re: noisy p90
Funny you should ask since I was planning to post directions on how to do it!  
After taking the pickup apart carefully, flip the magnet over and reverse the coil wires (one of which is soldered to the ground so I used some 24 ga bus wire insulated w/ 1/16" heat shrink tubing to extend the other lead). To make sure that you actually reversed the magnet you might want to test it with a bar magnet and the other pickup.  
I did this mod on a Epiphone Casino (which originally required me to mount the P-90 guts inside the Epiphone covers (after reaming out the holes to adjust the screws).  
I was so impressed by the results that I tried to do the same with the humbuckers on my LP in coil cut mode- and guess what? It didn't reduce the hum one bit! (I figured out later how to do that: you run the hot signal lead to the middle tap wire on one of the pickups; the middle tap wire of the other pickup is connected to ground.) By testing both combinations you can select either the outer coils or the inner coils like on a PRS 5-way selector switch!  
Getting back to the P-90's, if they are mounted in plastic cases, you ought to try shielding them. Dan Torres recommends wrapping the bare coil wires with one wrap of a cloth tape first (I use rayon adhesive tape) and then cutting out copper foil to go around the coil. Solder the foil together carefully, running a thin length of the copper foil tape to the ground shield connection. Dan sells a shielding kit for around $5.00 or you can try ordering DATAK cat# CF-3 from your local electronics parts house ($3.85 for 65 sq inches).  
There is one caveat with reversing the coil wires on any pickup: check to see if there is ANY continuity between the pole pieces and the windings (after you've disconnected any ground wire from either lead). If you get a reading you may get hum from that pole piece(s) if you reverse the coil.  
Good luck  
Steve Ahola