P-J wiring with series/parallel option question

[Shivan]

Hi all,

I have decided to change the pickups on my P-J bass and to add an additional functionality for which I didn't find an adequate wiring scheme so I'm kindly asking for some input.

I have purchased a P-QP pickup and J-hot stack pickup to replace my existing ones, but I would also like to add series/parallel option to my current bass as well.

On the Seymour Duncan site I have found a following wiring scheme:

http://www.seymourduncan.com/wiring-diagrams?meta_params=bass-options,2-pickups,neck-pb,bridge-jbstk

which is a basic P-J wiring scheme

I have also found an older Seymour Duncan scheme which is no longer available on the site:

https://imageshack.com/i/p8m6yw52j

My question is, can I use the above Jazz Bass wiring scheme to have series/parallel P-J combo where the green wire from the hot stack J pickup should go to the bridge volume pot and the black wire should go the neck volume DPDT switch and if not what would be the proper wiring scheme?

Thanks in advance

 

[Funkfingers]

Re: P-J wiring with series/parallel option question

Welcome to the forum.

What precisely do you want to have switchable between series and parallel?
1) The two pickups with respect to each other
2) The coils within each pickup with respect to each other.

Generally, forming a series link between two dual coil pickups, whose respective coils are wired in series, leads to Mud City.

Switching the coils of the stacked coil J pickup between series and parallel modes will result in a small difference in output and midrange fullness.

Switching the coils of a P pickup between series and parallel modes will result in a more noticeable change in output and midrange. Series will be the familiar P sound. Parallel is a pretty good match for a J pickup positioned nearer to the bridge.

Obviously, to make a Duncan SPB-3 switchable between series and parallel interconnection would involve modification of the output conductor wires. This will invalidate the guarantee.

 

[Shivan]

Re: P-J wiring with series/parallel option question

Hi Funkfingers,

thank you for your prompt reply and explanation. I had in mind to put the pickups in series/parallel with respect to each other since according to the Jazz Bass wiring scheme it states that series position offers a boost in output and mid-range which doesn't sounds bad, but you said that this leads to Mud City. Can you please explain why this exactly means and why this idea is bad?

Cheers

 

[Funkfingers]

Re: P-J wiring with series/parallel option question

The Jazz Bass schematic to which you refer is specifically for single coil pickups. Single coils, connected in series and in phase, result in a boost.

The Hot J Stack and P pickups are dual coil pickups. Two coils in series, connected in series with two more coils in series, adds up to four coils in series. This is where the "mud" originates.

Hot Stack and QP pickups are comparatively high output to begin with. i see little advantage to boosting their output any further.

In my opinion, the best ways to increase the sonic versatility of your particular bass guitar would be with active EQ or by introducing series/parallel switching of the coils of the P pickup. (For control cavity dimension reasons, an EQ pedal might be the easiest option.)

On stacked coil pickups, the lower coil is mainly for hum-cancelling purposes. It is too far away from the strings to contribute much signal. Consequently, the change between series and parallel modes is limited.

 

[Shivan]

Re: P-J wiring with series/parallel option question

Hi Funkfingers,

thank you again for clearing this out and saving me a lot of time and issues down the line.... I would just have one more question if you can advise as well. I'm mostly playing bass finger style, would I gain some more "brightness" to the output sound if I would replace 250k pots with the 500k ones on my P-J?

Cheers

 

[Funkfingers]

Re: P-J wiring with series/parallel option question

On paper, a 500k pot should have less of a muting effect on high frequencies than a 250k. Whether these frequencies will make much difference in a full band mix is debatable.

In my opinion, you would obtain a more noticeable improvement by using high quality control pots and/or brighter strings.

 

[Shivan]

Re: P-J wiring with series/parallel option question

Cheers Funkfingers,

thanks a bunch for the info provided .