PJ pickup

[David Schwab]

When Rodent says Single J, I think he means Single coil
So a Single J with a P is 3 coils and they will not be humbucking or am I missing something?
He has them humbucking with the split J, that is 4 coils.

The P is a humbucker, the single coil J is not, so they will not hum cancel together.

But he was also saying here was a phasing issue with one half of the P and single coil J together. That means the P is wired up wrong.

The only way to make the whole thing hum canceling is; use a split coil J, or do what Duncan is doing with their new PJ set, they have the P set up non humcanceling (NOT RWRP), so the P and J will hum cancel together. But then you are stuck with a situation where either pickup soloed will hum.

Personally while I like the tone of single coils, I refuse to listen to hum, so I don't use them. I find various hum canceling versions sound just fine. Split coil Js can often sound a little fuller, but that;s a good thing when they are at the bridge, and used with a P, which always over powers the J.

[big_teee]

DS, how does your J with the mini blades sound?
I'm with you on that, I don't do Hum.
T

[David King]

Won't switching the phase of 1/2 the P to make it non- humcanceling with it's other half when in parallel with the J work? I admit it's a finicky switching job but I'm pretty sure that's how Fender dealt with it on some PJ models. You may need to have 2 pairs of magnets on the J inverted which brings you right back to split j issues. I need to try it and see if it works I guess.

[David Schwab]

DS, how does your J with the mini blades sound?
I'm with you on that, I don't do Hum.
T

It sounds as much like a single coil as something like a Duncan Cool Rail. I didn't try and make it sound like a single coil, or a Jazz pickup, but originally wanted it to sound like my full size soap bars. But because I have limited room to wind on, it's not wound as hot, so it has a nice bright top end and a full low end and mids.

Won't switching the phase of 1/2 the P to make it non- humcanceling with it's other half when in parallel with the J work? I admit it's a finicky switching job but I'm pretty sure that's how Fender dealt with it on some PJ models. You may need to have 2 pairs of magnets on the J inverted which brings you right back to split j issues. I need to try it and see if it works I guess.

No, because on the P each coil has opposite magnetic polarity. If you reverse the electrical polarity of one coil, then one half will be out of phase with the single coil J.

The output of a humbucker is a composite of the two coils. But in the case of the split pickups, you can have a situation where one half is out of phase with a single coil.

You can make a split coil with the same polarity magnets on each half, and it will work as a humbucker, but then it can only be paired with another split coil set up the same way Delano does that with some of their pickups, probably to prevent phasing issues when bending strings. If you then wire it so it's in phase with a single coil, it will behave like a single coil, and will hum. But it will hum cancel with another single coil.

[Rodent]

I have my split P's E/A coil fwd wound with N up, and the D/G coil rev wound with S up. the split-coil J matches this configuration

just to mix things up a bit I wound a split P set with heavy 42 wire, and really like how it opened up the upper mids some while darkening the highs a bit. it pairs very nicely with the split-J set

[Rodent]

Update: I've been making the split-coil J4 for my PJsplit4 set for a while now, and am getting excellent consistency in the physical build, the overall tone, hum cancelling, and the volume balance with the split P pickup. here's a peek at the latest pair of split J4 bridge coils I wound and assembled.



I added a copper foil grounding strip across the bottom of the poles, and this has eliminated the grounding buzz when a player touches the magnets with their finger while playing. I'm going to swap out the stainless screws in the keeper plate for brass in the next batch, and the swap for a smaller screw in the next batch of flatwork I cut

One thing I also changed was the hot lead color on all my bridge pickups - when it's late and you're rushed for time, I found it easy to grab the wrong hot lead when soldering up the controls. changing the bridge hot to red eliminates this potential for rework (due to blend pots working backwards like a Sadowsky bass)


my next challenge is to morph this design into a 5-string version. to get started, I simply hacked a set of J5 flatwork into two unbalanced coil sets and then assembled the bobbin. once I have this down, I'll get to cutting the production grade flatwork



I have two J5 split sets I need to ship by early April, so the clock is ticking ...

[David King]

Getting those two halves to balance is a PIA. If you go turns area to completely cancel hum you'll end up with the two string side hotter and will have to reduce the Gauss accordingly.
Carey's first sets didn't balance at all and I had to send them back until he figured it out. I'd start with 5mm x 20mm A5s on the three string side and drop down to .188" x .750" A5s on the 2 string side.
Getting rid of the field cancellation between the A and D strings is the next hurdle which requires more fine tuning. You might have to stagger magnets.

BTY why are your eyelets on the top of the coils? Is that to prevent shorting of the connections against cavity shielding? Or wire strain relief? I like it.

[big_teee]

Very Nice, Mr Rodent.
Thanks for sharing.
I Like the bottom piece with screws.
That would make it easier than trying to line up the 8 pole pieces to a separate bottom piece.
What is the purpose of the 3 wires? Can you get by with 2?
T

[Rodent]

David - exactly what I suspected re balancing. I have a fresh 6lb spool of 43AWG to get this worked out - hopefully it's enough to get this design worked out

and sorry to break the news - but that's the bottom of the bobbin where you see the eyelets. I wind my single coil set a little shallower so the wire (as a whole) is a bit closer to the strings

[Rodent]

thanks Terry

that's exactly what I discovered in the process of making multiple sets - there has to be an easier way that works just as good or better. my first couple of test sets were simply hot glued into a pickup cover ... not a good solution to send to a customer

the third wire is a ground led attached to the copper foil on the bottom of the magnets. it connects to ground just like the black lead. I can get by with two leads, but you'll get the typical grounding buzz you get when your finger contacts an exposed magnet. while this doesn't eliminate 100%, it does knock down about 85% of the noise IME

[David King]

I've had to jump through a lot of hoops to avoid winding these with 43 AWG. Gauge probably doesn't matter as much as I thought when I started. I have yet to prove that out though.

It's easy to get in the ballpark re turns*area with just the math, you'll want about a quarter to a third more turns on the shorter armature. The problem with using shorter magnets to reduce Gauss is that then the two coils won't stay balanced as you get closer or further from the strings. A longer magnet just throws it's field further. Bartolini just tossed a steel plate on top of the lower turns coil to even up the signal strength. That works on an all steel armature but it changes the tone of alnicos pretty significantly.

[big_teee]

You have it worked out.
Instead of the 3 wires twisted, I would probably go with this.
2-Conductor Shielded Guitar Pickup Wire
I keep it on hand, and use it and the 4 wire on everything except vintage fender pickups.
You can also change polarity with it having the two wires with shield.
Thanks again for sharing.
T

[Rodent]

when working this out, I opted against the multi-conductor wire due to the added 3" of lead that extends to the opposite end of the far coil. it's a lot of waste of that $$$ fancy wire, and twisting is super simple to do with a hand drill after everything is all connected up and tested.

I like the multi-conductor wire you suggest when used in a side-by-side dual coil type arrangement, where all of the leads are connecting in close proximity. there's not much high $ waste in this scenario

[Rodent]

getting verrrry verrrrry close on having the pairing completed within each coil set and the pair



I should be field testing these by this weekend if all goes well

[David King]

I'll be curious to hear your results Rod. It looks familiar. I discovered that I could glue the butt ends of the flatwork very securely with CA.