PJ bass wiring problem

[StarryNight]

I wound a P bass pickup and installed it in a Fender bass with J at the bridge. The reason I was asked to make one was the original P was way too hot compared to the J and the owner wanted a more balanced output. I whipped one up and I thought I wired it properly but when both pickups are full volume they cancel each other out drastically. I assume that one of the bobbins on the P is cancelling out the signal on the J. How does one get around the problem (if that's in fact the problem)?

fyi I connected the two starts together on the P. Maybe I reversed the ground and the hot at the pot?

[shane1b4u]

Ha Ha

Where's that David Schwab guy when ya need him? Don't worry, he'll be by, he's the bass guy. He'll be able to help I'll bet.

[David Schwab]

Does it cancel out on all four strings? If it does, then just reverse the polarity of one of the pickups. They are out of phase with each other.

If it's only canceling out on a pair of strings, then you need to reverse that one coil on the P pickup.

[StarryNight]

The whole thing cancels out. He's coming over today with the bass. I'll report the results. Thanks DS.

[David Schwab]

The whole thing cancels out. He's coming over today with the bass. I'll report the results. Thanks DS.

Just swap the two wires from one of the pickups. That will fix it right up!

[David King]

The main problem with P-J set ups is that if you get the P and the J to cancel hum together then the P alone will be noisy *unless* you switch the polarity of one half of the P when it's soloed. You need a dpdt switch to do this, it can't be accomplished with a blend pot or two volumes that I can think of (It would be pretty cool if it could)
The other obvious option is to wind a split J that matches the split P.

Best of luck.

[David Schwab]

David, I'm assuming his P is set up like a regular humbucker and the J is a regular single coil, in which case you wont get the two to hum cancel.

His issue is they are just out of phase.

[David King]

Sure they will cancel if you want them to and the magnets are charged appropriately. Fender has been doing that for decades on their P+J models but they use a mini toggle pickup selector not a blend pot.

[mkat]

I think David S means that keeping the stock setup (no mod ie. switch) the way it is on that particular bass the two pickups together won't cancel the hum. The switch or humcancelling bridge pickup are options that could be presented to the customer.

[David King]

As far as I know, that would not be the stock set up but the only PJ special I've ever looked at was a MIM job from about 1999. Who knows what other configurations Fender came up with in the meanwhile.
I'd think that going to a non humcanceling config would seem a major step backwards.

[StarryNight]

lesson learned

well boys, the client returned the pickup before I could fix the problem. Being a relative beginner at bass pickups I have learned a valuable lesson. This was an example of what happens when the client doesn't get exactly what he asks for. Even though the fix would have taken less than 5 min. he wasn't satisfied with what he heard, got scared off and aborted the whole transaction. I can't blame the client, but I know had he been more tolerant, he would have walked away satisfied. A combination of his personality and my inexperience resulted in a lose/lose situation. To back up, I did the install (I like offering that for local players) and gave it back to him not realizing the P and J were out of phase. When he plugged in, he didn't like what he heard, removed the P I wound and returned it to me. I feel a little bruised but wiser for the experience. Next time I'll be more careful. Can't win 'em all.

[David Schwab]

Sure they will cancel if you want them to and the magnets are charged appropriately. Fender has been doing that for decades on their P+J models but they use a mini toggle pickup selector not a blend pot.

Every P/J I have seen has a regular P pickup, where each half has opposing magnetic polarity. Having them both on does not hum cancel the J pickup, since there is no hum in the P's signal.

Also since the P is wound hotter than the J, they wouldn't hum cancel very well even if they were both single coils. Having a switch or a blend doesn't matter.

A regular customer of mine has several Fender Aerodyne P/J basses, one with Barts and the others with the stock pickups. They all have regular hum canceling P pickups. One bass has a blend, and the other has a Gibson style toggle switch and two volumes that was wired up Gibson fashion. I changed them to work like a Jazz bass. It didn't, and doesn't hum cancel the single coil Jazz pickup.

If the P had in phase coils and opposite magnets, half of the strings would be out of phase with the J. This would also be true if the P had the same magnet polarity on both halves, and were wired out of phase for hum cancelation (that's why you can't mix Delano split pickups with other pickups). There would be no sense in making the P non humbucking, since that's what the design is partly for.

Getting back to the subject at hand... I always test replacement pickups for phase when installing them. You just never know exactly what you are going to get unless you wind both pickups.

[David King]

I have a Fender MIM PJ set in my attic which I need to dig out now, I'm interested to see if the P is all the same polarity or N and S. Obviously the only way to get the combinations I'm talking about the P would need all the same polarity up to work together with the J. (Unless the J uses split magnets too.)

[David Schwab]

The J can't use split magnets unless it has two coils, like the DiMarzio Model J.

There has been some threads at TalkBass where people were saying their P/J bass hummed when the J was in the circuit, and wondered what they could do about it. The answer was get a hum canceling J pickup.

[David King]

The J can't use split magnets unless it has two coils, like the DiMarzio Model J.

I don't see why not? What does it matter if two of the strings are out of phase with the other two on a single coil pickup (when it's soloed). It should only matter when two pickup's signals are out of phase on the same string or strings. No?
see diagram below of 3 coils, dotted lines are strings:
P J

n...............s
n...............s
.....s..........n
.....s..........n

A true split coil J would be a better way of joining a P and J -I agree but it's not the only way to do it methinks.
I guess an experiment is worth a few dozen words...