Fender American Deluxe Jazz Bass Pickup
Mods when used with a Z-Mode Preamp
When are these mods needed?
These mods only apply if ALL of the following are true:
1) Your Audere preamp is a Pro JZx preamp. This mod is not required with the New Audere Jazz Preamps.
2) Your bass has Fender American Deluxe Jazz stock pickups.
3) The pickups have the pole pieces grounded.
Can I tell by looking at the pickups whether they need the mod?
If your pickup covers are the originals you can look at the covers
1) A cover with no writing on it is usually a Shur pickup which does not require a mod
2) A cover with Noiseless written in Gold script is Fender's 1998-2005 design and is being returned to in 2015 - this pickup does not require a mod
3) A cover with SCN stamped into it from 2005 to 2009 requires a mod - see how further down the web page.
4) A cover with N3 in silver letters on it from 2010 to 2015 requires a mod - see how further down the page
Can I do a simple test to see if I need to make a mod?
1) Turn your amp down to a low volume.
2) Slowly push the string into the pole piece.
3) If you hear a low volume pop that's normal - the magnets will suck the string into the pole pieces when the string gets close - so no mod is needed
4) If you hear a really loud pop then you probably need to modify the pickups.
Why are Mods need?
Mods are need with some versions of the stock pickups to separate the pole piece ground from the pickup common wire.
If your pickups require the mod and it is not made when the string hits the pole piece then it will pop extremely loudly.
This condition is fixed by separating the pickup common from the pole piece ground so now the pole pieces are grounded just like the strings.
Why did Fender connect the pole pieces to ground?
Well we kind of did this one to ourselves - back in 2003 we published an Application note which showed the advantages of grounding pickup pole pieces. If the pole pieces are ungrounded, like on a traditional jazz pickup, and your finger touches a pole piece and the string at the same time then your bass will hum. And if you happen to have a static charge on your body the bass output will pop loudly. This is totally independent of any preamp - it happens with a passive jazz. We just exposed the issue.
What we demonstrated in the application note, which was news at the time, was that if you take a conductive adhesive foil strip and adhere it to the back side of the pole pieces and ground the coper foil with a new wire to ground then the hum and popping will be reduced greatly to an insignificant level.
Today several pickup makers ground the pole pieces - Fender did this with a circuit board on the bottom of the pickups which is a good technique. Most pickup manufacturers like Aguilar, Nordstrand and even Fender on other pickups understood the benefits of keeping the pole piece ground separated from the pickup coil so a 3rd wire was added.
For the stock pickups in the American Deluxe Jazz Basses Fender only used 2 wires and this creates a problem for our Z-Mode preamps so this web page explains how to take your 2 wire pickup and create a 3 wire version.
Can the mod be Reversed?
Yes this is really easy - we are electrically separating 2 parts of the pickups.
In the unlikely event that you want to reverse the mod the simplest way is to take the 2 wires and connect them to the same place the one wire would have gone.
In this case the 2 wires will always be going to ground with a passive bass or other preamps.
You could also unsolder the extra wire and use a small jumper on the bottom of the pickup if you prefer to reverse the mod this way.
Will the mod change the sound of my pickups?
No for the SCN pickups which are the most commonly modified versions.
Yes/No for the N3 pickups - the mod I recommend makes them sound much closer to Fenders standard single coil pickups but without the noise which is how they are sold by Fender. I also explain how to mod them to work with the original Notched Filter response if you like that sound.
How to mod "SCN" (Samarium Cobalt Noiseless) pickups?
Under the pickup covers they look like this:
The SCN pickups need to be modified by making a small wiring change on the bottom of the pickup - you cut 1 wire jumper and add a new wire to ground.
This change will not effect the sound and is always a good mod - it is electrically separating the pickup pole piece ground from the pickup common.
Below is the location of the wire jumper to be removed (just cut out the existing wire with nippers) which is connecting the triangle to the square pad.
FYI - The triangle shaped pad is the pickup common. The square pad is the pole piece ground. The round pad is the pick hot connection.
After you cut out the wire jump - you add a new wire from the square pad which will go to the electrical ground off the center pin of the jack as show in the picture below.
You can use any convenient sized and type of wire to make this electrical connection.
This completes the mod.
How to mod N3 pickups?
Under the covers they look like this:
N3 pickups need to be modified to work with a Z-Mode preamp but IMO the best mod will clearly change the sound of the pickup.
My recommended mod will remove a Notch Filter response from the pickups mid range. Removing the notch filter will make it sound much closer to a traditional Fender single coil pickup.
This mod has not been used by many of our customers because most of them have long ago replaced the stock N3 pickups with after market versions in order to get a more traditional sounding pickup.
Looking at the picture below - Fender this time connected the pickup pole piece ground which is still a square pad as it was on the SCN to the pickup common pad (where the green wire goes) with a large trace on the printed circuit board. Normally I would have cut the trace between the pickup common and used the square pad by putting a wire into the square pad's hole but in this case it was not possible due to plastic on the top side of this board that I did not want to melt.
The mod procedure is:
1) The Square pad is connected to the copper flooded board area which grounds the pole pieces by a thinner trace. The plan is to break the electrical circuit at that point. If you look carefully at the board below between the square pad and the flooded plain you will see I have severed the tracking by taking an Xacto knife and completely cutting through the metal trace. Make this cut slowly in multiple passes and take your time - you must completely remove a strip of the copper but not go too deep - it is not hard, the board is at least 20 times thicker than the copper so just take reasonable care.
2) Optionally, if you have a DMM test the resistance between the green wire and the back side of one of the pole pieces - your meter should read infinite resistance or no connection after the cut.
3) I recommend you stop and skip to step 9 - the pole pieces will hum if you touch them but the notch filter response has been removed so the pickups sound more like traditional jazz pickups.
4) If you want the Notch Filter response then proceed with step 5
5) A spot on the solder mask over the copper is selected (you can select any spot) for mechanical removal. You can use the Xacto knife tip to scratch off the solder mask. The color of the spot will change from Red to a Silver color as the mask is removed. You only need to remove a very small area where a wire will be soldered to the copper plain.
6) Pre-Tin the area where the solder mask was removed to make it easier to solder on your wire.
7) Solder on a new wire - the other end of this wire will be connected to the common ground wire (Grey/White) which comes off the center pin of the output jack and also grounds all other shielding in the bass.
8) Optionally, with the DMM test the resistance from the other end of your new wire to the back of the pole pieces - the meter should read < 1 ohms of resistance.
9) Put some insulator into the cut area - lacquer (nail polish) works well at these voltages.
This completes the mod
541 867 6878
4909 S Coast Hwy, STE 295
South Beach, OR. 97366
Pro JZx Series