Do 5-string Split P pickups have to be symmetrical?

[el_Bajo_Verde]

I've noticed that Fender and Squier's 5-string P-basses have asymmetrical split pickups, but others have symmetrical pickups. Is it important for the pickups to be the same size?

Fender/Squier asymmetrical

Mitchell 5-string symmetrical

Sandberg symmetrical

 

[Stevorebob]

I'm a fan of asymmetric P-5 p'ups. I wish more independent makers made assymetrical replacement p'ups for Fender basses.

 

[Chris 'Wighat' Jordan]

I think it's purely an aesthetic consideration.

 

[hoangduong212]

I think it's for aesthetic reason only, no different between them

 

[two fingers]

Yeah even the pole piece placement isn't a huge concern. The collective of all the pole pieces on each pickup create on big magnetic field, not 2 or 3 smaller individual ones.

The best analogy I can think of is a fist and fingers. The pickup creates a fist, not 5 individual fingers sticking up.

It matters exactly none.

 

[Stevorebob]

Is there much difference in the humbucking-ability of the two? I would think for the greatest rejection of hum, that at least, the two coils should be essentially identical, no?

Fender asymmetrical P-5 pickups are hum free. There is no compromise there.

 

[MPU]

I've made a split coil p-pickup with same size coils. One coil has magnets for three strings, the other has magnets for two strings plus two plastic slugs, both wound to 9500 rounds of wire. Totally hum free. I've also made a split coil j-pickup with different size coils. One coil has magnets for three, the other for two strings, both wound to 10000 rounds of wire. Also totally hum free. I see (or more likely hear) that both symmetric and asymmertric coils can make a functioning humbucking pair.

 

[Stevorebob]

Are the two coils exactly the same - wire length, number of turns, etc., just one half has two poles and the other has three?

I can't speak to the construction of the pickups. I have a Fender AS Precision 5 with the asymmetrical pickups and can verify that it is noiseless.

 

[Rickter]

I've noticed that Fender and Squier's 5-string P-basses have asymmetrical split pickups, but others have symmetrical pickups. Is it important for the pickups to be the same size?

Fender/Squier asymmetrical

Mitchell 5-string symmetrical

Sandberg symmetrical

Having recently bought a Fender American Precision 5, the asymmetrical P pickup was of concern. Fender seems to be the only manufacturer using this offset design. Most every other manufacturer and aftermarket pickup manufacturer has chosen to go with the symmetrical shells approach. Seymour Duncan has been one of the few I have found whom will build a pickup in the Fender style, but most of them are an order from the custom shop.

 

[Stevorebob]

Having recently bought a Fender American Precision 5, the asymmetrical P pickup was of concern. Fender seems to be the only manufacturer using this offset design. Most every other manufacturer and aftermarket pickup manufacturer has chosen to go with the symmetrical shells approach. Seymour Duncan has been one of the few I have found whom will build a pickup in the Fender style, but most of them are an order from the custom shop.

Nordstrand also makes the Fender-style asymmetrical P-5 pickups.

 

[lz4005]

Thanks guys. So this means that the coils can be "unbalanced" and still provide total rejection. Interesting.

They still have to be electrically similar to each other in terms of the number of rounds of wire, etc.
But that has nothing to do with what they look like on the outside.

 

[honestjohnny]

Yeah even the pole piece placement isn't a huge concern. The collective of all the pole pieces on each pickup create on big magnetic field, not 2 or 3 smaller individual ones.

The best analogy I can think of is a fist and fingers. The pickup creates a fist, not 5 individual fingers sticking up.

It matters exactly none.

The stock pickup on Bronco basses is a Strat single coil and is replaced oftentimes by a Strat Hotrails. The pole pieces do have some overlap in field and the fist analogy is a good one, especially with the dips in between the knuckles describing the lobular shape of the fields. This can be heard particularly in Jimmy Page's solo on Heartbreaker, where he bends the string out of the field of his telecaster's bridge pickup (listen carefully to the drop in volume). That said, this can be avoided by adjusting the pickup closer to the strings until the curve in the field can't be seen by the string. Symmetry is a huge component of human aesthetics (rarely found in nature) and straight pickups do this better than split coils. OTH, for closest to single coil tone, a split coil as in DiMarzio's humcancelling Jazz style pickups or with very thin, closely placed rail pole pieces, is best. However, as many have noticed, the tone is often more pleasant when the lower strings have their pickup closer to the bridge and the higher strings closer to the neck. And of course, the split P is better able to account for the fingerboard radius. Of course, a bridge piezo and some clever EQ and filtering eliminates the need for any of these considerations....

 

[megafiddle]

The two bobbins in Fender's asymmetric 5 string pickups appear identical except for length. Without actual data, we can only guess at how well balanced the two coils are. A quiet asymmetric pickup is not necessarily an indication of perfect balance. Even a single coil J pickup can be pretty quiet in certain environments. Imbalance does reduce the amount of hum redution, but reduction is still there and can still be quite good.

If both coils were wound with the same wire gauge and same number of turns, the inductance would be greater due to the extra length and the presence of two extra pole pieces. The capacitance would be greater also due to the extra surface area of the wire. Also, the resistance would be greater due to the extra wire length. This increase in resistance would have very little effect on response though.

The overall effect of all this would be to lower the self resonant frequency of the larger coil with respect to the smaller coil.

With a split coil pickup, only one coil of the pickup is ever generating a signal for any particular string. The signal generating coil has a peak in the response.The other coil is in series with the generating coil and forms a notch filter. With identical coils, the notch and peak cancel out.

However, something interesting happens with unbalanced coils, where the peak and notch separate from each other in frequency. In the response below, one coil has been increased in all it's parameters by 5 percent.

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