Help! Mystery wiring replacing pups, and now a false octave / synth vibe?

[AndWhy]

Hi Team Bass Chat, 

 

inspired to change my pick ups recently, I finally gave it a go… 

 

Surprise number 1: Prepping for a swap as per the wiring diagram, I was surprised to note my bass (Fender P Special with PJ pups, with a life before it was mine!) had some odd wiring… All hots fed into a push/pull tone pot (which I didn’t know was push pull) and then from there fed to the 2 x volumes. No idea what the push pull does!?
 

So, I decided to trace the wires and just replace like for like as I found them, but with new pups for old. Simples. It is a bit of a car-crash, but don’t think I made it worse… Or so I thought… 

 

Surprise 2: On the higher strings (and noticeable on all) I get a gnarly octave /synth / chorus sound. 
 

Assumed it might have been string height, and overly sensitive magnets - so reduced the pickup height to make the gap as big as possible (+10mm), and nothing. Still there. 
 

So, next steps suggestions?? Anyone had anything similar? 
 

One option I’m toying with is just to get some new pots and start fresh with the wiring. Feels like a nuclear option, but would rule out any wiring issues…. 

 

Other option involves a trip to the tech! 
 

(Rotosound swing bass 66 strings, and Seymore Duncan Duff McKageb PJ pickups - so a quarter pounder split coil, and a jazz hot stack) 

 

pictures are “before” I didn’t think to get an “after” 😂

 

any comments appreciated! 
 

(PS Might be some Aguilar PJ pick ups finding themselves on the for sale forum once I’ve got this sorted 👍)

[Andyjr1515]

There's no easy way of answering what the push/pull pot is doing...and with the amount of solder around and about, whether anything is shorting...but that is the bit where there is some sort of out-of-phase stuff going on, I am sure.

 

Looking at the two other pots, it looks like it started off as a standard  neck vol/ bridge vol/ master tone set up.  It is - and can be - a fairly straightforward circuit (see the Fralin P/J circuit below)

 

 

 

So I would suggest that the only pot you need to change is that push/pull one.  Just fit a standard tone pot / capacitor instead and wire up exactly as above where the two whites from the pickups go to the respective middle position of the two existing volume pots, the two blacks from the pickups are earthed, as are all three pots, and then a simple feed from the middle pin of the tone pot to the 'hot' peg of the jack socket, and earth to the other one.

 

Edited 2 hours ago by Andyjr1515

[BigRedX]

Do you have a multi-meter and do you understand what your present wiring and all the controls are supposed to do if functioning correctly?