difference between single coil P Bass and J bass
 

What are the physical differences, impedance, magnets, etc., between a single coil (1951) P Bass pick up and a J bass front pick up?
Does the two poles per string make that much difference in the sound?

I am trying to get more punch out of the front pick up of a JJ type bass (70's pick up location) , and, to my memory, the single P Bass PU was all punch.... Maybe there is a J front that makes that sound, but I haven't found one yet.

If I recall right the coil is physically narrower but taller with taller and bigger-diameter magnets, and there's the issue of polepieces directly underneath the strings. The polepiece geometry definitely impacts the sound.

The P51 first of all is nothing but the pickup of a Fender Hawaii guitar, equiped with for pole pieces. It was easy to manufacture, cheap and it worked ...
(same with the Esquire / Nocaster / Tele bridge PU).

In the mid / late 1950s Fender wanted to create a more "indirect" sound. He experimented with 7 pole guitar PUs, so that every string had one magnet left and one right. But the result was not satisfying ...
I think this lead Leo Fender to the 8 pole piece P57 pickup. These pickups also had the "new" Gibson / Seth Lover humbucking effect, without paying any patent fees to Gibson - because of split coils and single magnets.

Maybe the P57 had too much punch for Fender and so the 60s bass got SCs again - but with the 8 magnets of the P57. Result were the J-PUs ...

"Punch" normally means low mids (which "punch" into your stomack) - P57 PUs ...

Have you put the neck PU as high as possible? The higher the PU is, the more punch you get (not only output). A J-Humbucker might help? But it might sound too "indirect"?

A series/parallel wiring of your PUs will give more punch, too! But the output might be too high, compared to the other settings ...

The punch of a P51 might also have to do with its neck ...

ive read tht the splitcoil pu,s actually were two mandolin pu,s.

It's that strong attack that I'm after - great for Tower of Power / Meters type music. I have tried various PU settings, but I can't seem to find the sound that I like. I tried a replacement J front PU, but it didn't do it, hence the questions about pole piece location, windings, etc. Thanks...

Ah!!!!!!!!!!

Attack is something different than punch!
And attack is what I described as "direct/indirect" ...
To may mind, most humbucking JB pickups would be wrong.

Maybe SD Quarter Pounders would be right? But I'm not shure ...

Have you considered DiMarzio Model J's? I have them in my Geddy--I can run just the neck pickup and get a very pbass-like tone. In fact, as I understand it, they are a split-coil design in a J-bass housing, so it's essentially a pbass pickup.
Plus, they're quiet. Really awesome pickups--transformed my Geddy, like night and day....

Thanks for the tip on the Dimarzio's I'll look into it. To complicate matters, the bass is a 5 string PU size: 3/4" x 4" I expect I'll have to have a PU made, so I want to sort this it before i have one made. I have DP 547 (FS, BTW) from another bass, and I liked it, but didn't have want I wanted...

Rocco Prestia of Tower of Power plays a P bass. I'm not sure about the Meters, but if I were going to cover that I'd use a P bass as well. That fits with your definition of punch, but not attack. P's blend into the mix - that's their thing. They do that because they don't have a ton of brightness on the top end which is what most people think of as attack. They "punch" their way to the front of a mix if pushed.
I'd say, get yourself a split coil P style pickup.

I already have a split coil PJ.

Yeah the 547 is the Ultra Jazz--I had a Jazz with those too. I really liked them, but they're very different from the Model J (DP123), which really can sound very "p-like"--really strong mids and low-mids, as it is essentially a P/humbucking pickup.
Sadly, they don't make the Model J in a fiver!:(

You could try the Area J I suppose--but again they still look like a regular J pickup--not the unique beast that the Model J is:

http://www.dimarzio.com/pickups/bass