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Question about dummy coils and humbuckers
The 2013 Gibson LPJ Pro has push-pull volume pots which split the coils by running the center tap to ground through a cap (unlike a coil-cut switch which shunt the center tap directly to ground.) I can't read the value of the cap but I think it is too low because the resulting sound is very thin (but still not humcancelling.) The Donald Brosnac book on guitar electronics attributed this idea to Bill Lawrence which gives a brighter tone that has some humcancelling effect. (He used a 0.02uf cap.)
My first thought was to replace the caps with jumpers to ground so that they would be typical coil-cut switches. But what if I was to run the center tap to ground through a dummy coil? If wired and adjusted properly that should give me a single-coil tone with some humcancelling.
I just wired up a P90 bobbin with 400' of 32GA magnet wire that I picked up at Fry's along with a 10k cermet trim pot to allow me to dial in the desired amount of dummy coil. You usually get the best single-coil tone when eliminating ~80% of the hum (if you go for 100% the tone can get very unnatural.) I was planning to put those parts into a 2014 Gibson Melody Maker but I may test them out in the LPJ first just for the heck of it....
So my question is whether someone here has tried wiring a dummy coil with a PAF-style humbucker coil cut switch, and if so do they have any suggestions...?
Steve Ahola
P.S. The dummy coil on the 2013 LPJ is strictly optional but would be a big improvement for the 2014 MM which has two P90S pickups. Normally I would flip the magnets and reverse the leads to put a pair of P90's into* NWNP orientation so that I could use a single dummy coil but the P90S pickup has magnetic slugs like a Fender single coil pickup. It is a slick idea because it allows for soapbar mounting in the MelodyMaker which has a thinner body than a LP (the 60's MM and SGJr had dog-eared P90s.)
I ended up getting two of the 2014 MM's so one of them will have two neck pickups and the other will have two bridge pickups. Now if I was sure that the alnico slugs were not in contact with the coil wire I could use a press to push them through to the opposite side I would not have to swap pickups.
One complaint... why didn't Gibson call the new pickups something less confusing like "P90AS" (for Alnico Slugs) rather than "P90S" which sure looks a lot like "P90s" plural. (To be fair the treble pickup is a labelled P90 ST and the rhythm pickup is labelled P90 SR but that is not how the ad copy reads. )
BTW the P90S pickups are very similar in design to the wide oval pickups that Gibson used in their steel guitars in the late 40's. (The string spacing was much wider than their spanish electric guitars so they could not use regular P90's.)
The 2013 Gibson LPJ Pro has push-pull volume pots which split the coils by running the center tap to ground through a cap (unlike a coil-cut switch which shunt the center tap directly to ground.) I can't read the value of the cap but I think it is too low because the resulting sound is very thin (but still not humcancelling.) The Donald Brosnac book on guitar electronics attributed this idea to Bill Lawrence which gives a brighter tone that has some humcancelling effect. (He used a 0.02uf cap.)
My first thought was to replace the caps with jumpers to ground so that they would be typical coil-cut switches. But what if I was to run the center tap to ground through a dummy coil? If wired and adjusted properly that should give me a single-coil tone with some humcancelling.
I just wired up a P90 bobbin with 400' of 32GA magnet wire that I picked up at Fry's along with a 10k cermet trim pot to allow me to dial in the desired amount of dummy coil. You usually get the best single-coil tone when eliminating ~80% of the hum (if you go for 100% the tone can get very unnatural.) I was planning to put those parts into a 2014 Gibson Melody Maker but I may test them out in the LPJ first just for the heck of it....
So my question is whether someone here has tried wiring a dummy coil with a PAF-style humbucker coil cut switch, and if so do they have any suggestions...?
Steve Ahola
P.S. The dummy coil on the 2013 LPJ is strictly optional but would be a big improvement for the 2014 MM which has two P90S pickups. Normally I would flip the magnets and reverse the leads to put a pair of P90's into* NWNP orientation so that I could use a single dummy coil but the P90S pickup has magnetic slugs like a Fender single coil pickup. It is a slick idea because it allows for soapbar mounting in the MelodyMaker which has a thinner body than a LP (the 60's MM and SGJr had dog-eared P90s.)
I ended up getting two of the 2014 MM's so one of them will have two neck pickups and the other will have two bridge pickups. Now if I was sure that the alnico slugs were not in contact with the coil wire I could use a press to push them through to the opposite side I would not have to swap pickups.
One complaint... why didn't Gibson call the new pickups something less confusing like "P90AS" (for Alnico Slugs) rather than "P90S" which sure looks a lot like "P90s" plural. (To be fair the treble pickup is a labelled P90 ST and the rhythm pickup is labelled P90 SR but that is not how the ad copy reads. )
BTW the P90S pickups are very similar in design to the wide oval pickups that Gibson used in their steel guitars in the late 40's. (The string spacing was much wider than their spanish electric guitars so they could not use regular P90's.)