• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Jazz Shielding Pictorial (Big Images Warning)

#722
Howdy,
I want to switch out the pots and jacks in my Squier CV J bass. While I am in there I decided that I would like to shield the bass. I was wondering if I could wire according to the schematic in the PDF? I saw that he had something called a "blend" pot instead of a "tone pot" (which is what I believe I have), would I still be able to wire it up the same way? If not, is there another schematic out there that I should refer to? Thanks much!
 
#723
MelodiousThunk said:
Howdy,
I want to switch out the pots and jacks in my Squier CV J bass. While I am in there I decided that I would like to shield the bass. I was wondering if I could wire according to the schematic in the PDF? I saw that he had something called a "blend" pot instead of a "tone pot" (which is what I believe I have), would I still be able to wire it up the same way? If not, is there another schematic out there that I should refer to? Thanks much!
Click to expand...
The blend pot replaces one of the volume pots. The tone pot stays as it is.

You basically have two choices... vol-vol-tone or vol-blend-tone (some also call a blend pot a "pan" pot).
 
#724
Hi Melodius - Forgive me if you are not a rank amateur like I was before I did the exact same thing with my Squier VM fretless jazz. I strongly suggest you browse this thread for an excellent education on what you are about to do as well as the sticky on shielding basses. Be advised that Fender has wiring diagrams for many of its basses online: Invalid Link Removed I used the wiring diagram from a Jaco MIA fretless. Chat rooms at the Squier website aldo have excellent and useful information, as does the Stewart-MacDonald website and other bass parts websites.

Once again, if you are not a ham-fisted weekender like I was, my apologies. I will say shielding, re-wiring and replacing your pots greatly reduces (but does not eliminate) single coil type hum but much more importantly, it really improves the quality of the sound of the instrument.

My 2c.
 
#725
Thanks for the info! I've shielded guitars before (15 years ago!), and just want to make sure that I still know what I am doing! As far as schematics go, would it be best just to take note of how everything is wired before I take it apart and then just rewire everything back the same way when I am finished? I just thought that there might be a better way of wiring for hum reduction? Thanks!
 
#726
Hi all,

I have shielded my two fenders (one Jazz and one Precision) and I have experienced problems with both. So I would like any advice.

My Japanesse Jazz Bass was very noisy when I adquired it so I shielded every cavity with aluminium foil (I had not enough cooper foil at the moment) and placed a star point ground in a cooper strip at the pots' cavity. As a result, the bass is death quiet but the output signal is also very weak now. Prior to shielding I used to set the gain of my amp at 4, now I have to set it at 9 for the same result.

The other is a MIM Precision which was also a bit noisy. So I shielded the "common" cavity with cooper foil and place a star point ground in it. The result is an "ocassional static current noise". As long as I am touching the strings, there is no noise but, when I am not acting as ground, the noise comes in for one second or so and then disapears.

I have tried several ground connections, as I thouhgt I had a problem of potential differences in the grounding cage, but I think this is not the problem. I suspect that the cause of this problem could be at the pickup.

Note: Pickups' poles are not grounded (nor JB neither P).

Cheers,
 
#728
markinson said:
My Japanesse Jazz Bass was very noisy when I adquired it so I shielded every cavity with aluminium foil (I had not enough cooper foil at the moment) and placed a star point ground in a cooper strip at the pots' cavity. As a result, the bass is death quiet but the output signal is also very weak now. Prior to shielding I used to set the gain of my amp at 4, now I have to set it at 9 for the same result.
Click to expand...
Any time you have gain reduction, it means your signal is somehow getting grounded... maybe a "resistive" ground, but nevertheless. A full short to ground of course would mean no output. Recheck everything and make sure all signal wires are well away from the shielding/grounding, and isolate with insulation or electrical tape as needed.

The other is a MIM Precision which was also a bit noisy. So I shielded the "common" cavity with cooper foil and place a star point ground in it. The result is an "ocassional static current noise". As long as I am touching the strings, there is no noise but, when I am not acting as ground, the noise comes in for one second or so and then disapears.

I have tried several ground connections, as I thouhgt I had a problem of potential differences in the grounding cage, but I think this is not the problem. I suspect that the cause of this problem could be at the pickup.

Note: Pickups' poles are not grounded (nor JB neither P).

Cheers,
Click to expand...
You can't introduce a pickup problem by shielding and grounding unless you accidentally short something (see above). Any time you have noise that goes away when you touch the strings, it usually means there's not a good connection to the strings from the ground/shield, meaning the bridge ground wire isn't making a good enough connection (or maybe one at all). Maybe that's always been there, but masked by the other noise you just got rid of. Another thing to check, anyway.

Given that, even with great grounds and shields you can still have cases for noise that reduces or goes away when you touch the strings, but with proper grounding/shielding, it should be "as good as it can get" given a particular playing environment and pickup.

On pickup pole grounding, that can also help, but it can also affect pickup tone, and it's sometimes a challenge to get a ground wire to touch and remain touching all poles equally (and it needs to ONLY be on the bottom of the poles, which may not even be available on all pickup types).

Finally, generally speaking now, just keep in mind there's nothing you can do to completely eliminate hum if you have single coils in a J bass and you don't have both fully blended (which sets up a humbucking configuration). Any time you favor, or especially solo, a single coil, you get hum, period. The amount totally depends on the playing environment, which can vary greatly.
 
#731
#732
Forgive me for not reading all 37 pages. Has anyone tried this before?

To shield the tunnels on my PJ Warmoth I used the braided shielding from a short length of instrument cable. I cut the outer insulation off, pushed both ends of the braided copper together (which increases the diameter) then slid the core insulation and wire out. This left a hollow braided tube of copper. I fed the pickup wires through the tube then fed the entire tube into the tunnels. Once inserted I frayed both ends a bit with a needle and soldered them to the foil in the cavities on either side of the tunnels.
 

Attachments

  • Ground 2.jpg
    Ground 2.jpg
    61.8 KB · Views: 163
  • Ground 4.jpg
    Ground 4.jpg
    56.7 KB · Views: 156
#733
Ricnroll said:
Forgive me for not reading all 37 pages. Has anyone tried this before?

To shield the tunnels on my PJ Warmoth I used the braided shielding from a short length of instrument cable. I cut the outer insulation off, pushed both ends of the braided copper together (which increases the diameter) then slid the core insulation and wire out. This left a hollow braided tube of copper. I fed the pickup wires through the tube then fed the entire tube into the tunnels. Once inserted I frayed both ends a bit with a needle and soldered them to the foil in the cavities on either side of the tunnels.
Click to expand...
Yep. Technically, it helps, but how much difference it makes is debatable due to a fairly small RFI profile for the wires passing from one cavity to the next. Still, it is an improvement no matter what.
 
#734
Ricnroll said:
Forgive me for not reading all 37 pages. Has anyone tried this before?

To shield the tunnels on my PJ Warmoth I used the braided shielding from a short length of instrument cable. I cut the outer insulation off, pushed both ends of the braided copper together (which increases the diameter) then slid the core insulation and wire out. This left a hollow braided tube of copper. I fed the pickup wires through the tube then fed the entire tube into the tunnels. Once inserted I frayed both ends a bit with a needle and soldered them to the foil in the cavities on either side of the tunnels.
Click to expand...

If your pickups have shielded wires, the tunnels are not necessary. The shielding on the pickup wires will act like a tunnel. However, we must ensure the neck and bridge shielding must have connectivity to the ground. I use a plain wire to connect both bridge and neck shielding to the ground.

Vic is right, specially if your pickups are not using shielded wires.
 
#736
mlopbass - The first soldering I ever did was sealing the shield seams on my bass cavity. IMHO, just do the best job you can with all connections and make sure you get a good complete shielding seal, comparing your work to the tons of pictures on this and other threads and elsewhere online, and you will achieve a great improvement in sound. I did not use an ohm-meter but my bass sound is much improved.

If you want a direct answer to your question, I'm sure the more experienced who prowl this thread will help you.
 
#737
mlopbass said:
If the shielding inside my bass doesnt read 0 ohms with other points, how could i fix that. Im a beginner with all this electric stuff.
Click to expand...

A sensitive meter will read some small resistance even if it is all soldered correctly.

To see of your meter is reading what you need, first get a reading between two close points on the same continuous strip of copper, then compare that to readings across adjacent pieces of soldered copper. Readings should be close, but you may get a slightly higher reading as distance from the test points increases (again, with a sensitive meter).
 
#739
Hi Paul - Browse through this thread and you will find everything you need to shield your jazz bass. That's what I did. And if it's not in here, there'll be suggestions or links.

One tip, go to the Fender website and browse the schematics Invalid Link Removed to find your instrument's wiring diagram. Makes things a little easier
 

Latest posts

Top Bottom
Back