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Jazz Shielding Pictorial (Big Images Warning)

#563
#566
Hi there this is unbelievable thread! I read the first 15 pages, done a quick search but didn't find anything.

I am about the put some Nordstrand NJ4s in my jazz bass which has a Jretro preamp. I would have went for a star ground if there wasn't specific terminals on the unit for negative pickup wires. I think my best option is to connect the bridge ground straight to the jack and make sure there is good contact between the copper shielding and the control plate?

Is this my best option?

.... Just a quick thanks to everyone who made this thread happen! not only have i learned how to properly shield by bass, I've also (almost) learned how to rewire it!
Thank You!
 
#567
That should be fine. With the J-retro, the ground wires from the pickup connect into the J-retro unit rather than some common termination point. Strictly speaking then, you can't use a true star ground. But the result is pretty darn fine anyway. I did a shielding job on my J-bass with a J-retro, with the bridge ground connected to a screw lug in the main cavity. I also connected a ground wire from the pickup cavity to that screw. That works great, and there is no noise at all. It's a little easier than soldering the bridge ground to the output jack.

Davebass said:
Hi there this is unbelievable thread! I read the first 15 pages, done a quick search but didn't find anything.

I am about the put some Nordstrand NJ4s in my jazz bass which has a Jretro preamp. I would have went for a star ground if there wasn't specific terminals on the unit for negative pickup wires. I think my best option is to connect the bridge ground straight to the jack and make sure there is good contact between the copper shielding and the control plate?

Is this my best option?

.... Just a quick thanks to everyone who made this thread happen! not only have i learned how to properly shield by bass, I've also (almost) learned how to rewire it!
Thank You!
Click to expand...
 
#570
Official Ninja said:
Does anyone know if homedepot, lowes , or other common stroes in the USA carry this copper tape?
Click to expand...

Stewart MacDonald will have it, however if you are doing any volumes of work, try McMaster-Carr. Could probably do even better from Allied Electronics; but I use McMaster for all sorts of stuff on a daily basis at work. They have an outstanding website and ship very quickly, no minimum order requirements.

http://www.mcmaster.com/#copper-foil-tape/=5md129
 
#571
This mod was very clever... however many people seems to be missing one single detail on the design on the jazz bass...

If you look at the original wiring of a jazz bass you will notice that there are not ground connections from pot to pot and theres not ground lead from the jack; also you will notice that the ground of the pickups, body cavity and bridge are soldered in different pots rather than on just one pot...

These design was not the work of a newbie on electronics... Leo Fender knew what was star grouding and thats why he added the metal control plate on the jazz bass... all grounds, pots, capacitors, shielding and jacks are finally connected by contact to the metal plate and that makes the control plate the center of the grounding on the jazz bass... so in short words the jazz bass its already star grounded.

The same goes for many vintage strats... they had a thick aluminum or copper plate under the pickguard that was the center of the ground; so there was not a need for ground connections from pot to pot and finally to the jack or soldering the ground leads to the master volume... however this is not anymore since the pickguards now just have a thin foil of aluminum or copper with its not enough for making it the center of the ground connections.

Anyway that was a very nice shielding job but just moving all the wires to another point will give you the same result.
 
#572
erikmilan1987 said:
Anyway that was a very nice shielding job but just moving all the wires to another point will give you the same result.
Click to expand...
I needed you to back me up when I was debating this with another TB'er a while back. :)

The debate was anchored on the theory that, whatever resistance existed between different mechanically connected grounds was significant enough, that you could have "ground loops" that would be eliminated by literally connecting all grounds to a single solder blob/lug. I called BS based on the voltages and frequencies in use in an electrical guitar application, but the debate still ended in a stalemate. Now, if you wanna' get into high frequency stuff, and high enough voltages that a fraction of an ohm matters, ok... but not in an electric bass. Sorry. Not buyin' it. :)
 
#573
Thats totally right... well now everybody knows why star grouding on guitars is not necessary...

short asnwer is... ITS ALREADY STAR GROUNDED.

This is a lesson for those that thought that the jazz bass control plate was made for cosmetical reasons.

So ppl if you have a great jazz bass (good craftmanship) and want to reduce the noise in the signal just do a well made shielding with copper tape or/and buy hummbucking jazz bass pickups.
 
#574
Good morning:

I have a question regarding shielding and star-grounding of a newly purchased Epi Thunderbird Pro-IV - right out of the box it's had the standard hum that disappears completely when you touch the strings, bridge, etc., so last night I thought I would pop it open and see what was under the hood.

I found a decent layer of conductive paint in the cavity, and foil on the back of the control cavity cover, but the obvious no-no's were there...everything was soldered to pot shells, and no ground lug. I started by de-soldering everything from the pot shells, including the spare lugs from each pot. I did notice that on this particular set of pickups, though, there is the white wire from each PU that is connected to the blend pot, but there is a red (unused) wire from the pickups that is folded back under the heat shrink and seems to be unused. The braiding from each pickup wire was soldered to the shell of the blend pot.

I have removed all the negative/shield wires and will be working on things again tonight

Now, this bass has active circuitry and the negative line from the epoxy-covered brick was also soldered to the main volume pot shell, and the neg. from the battery goes to the jack.

Before I get back to it tonight, I just want to make sure that I know what's happening here - I've done similar shielding projects on many guitars, but never anything with an active peramp/battery system. A couple of questions that I had:

1. Can the unused wire from the pickups be used somehow, so that I can free up the braided shield for better use in grounding the pickups?

2. Right now the wire from the jack to the main volume pot is a single conductor w/braided shield. Is it better to replace this wire w/ a 2-conductor shielded wire and just not use the braid?

3. According to many of the articles that I've seen on shielding, including the guitarnuts article, can I just put all the equipment grounds and signal grounds together at a new lug, and then attach the bridge ground to that same lug?

Thanks in advance for any replies, and I just wanted to thank the contributors for a fantastic thread!

Regards,
Jeff M.
 
#575
Did a 5 string jazz shield/re-wire with star grounding. I'm wondering if there's a betters spot to ground to than I picked. Probably. It looks like rat's nest in there.

IMG_4875.jpg


IMG_4879.jpg
 
#577
gotta use up the whole roll somehow . . . :p

IMG_4973-2.jpg


IMG_4975.jpg


I don't know if I'm doing something wrong on this bass, but it doesn't seem to be as quiet as some other jobbies. . . obviously the P-bass is going to be quieter, but the differences with his one are:

star grounded to jack ground lug instead of screw-down lug in body
22 gauge teflon wire instead of 20 gauge
did not wrap foil over lip for "cleaner" install

I get hum even when both pickups are full up. . . granted, I tried an un-shielded jazz bass for comparison, and it was a REALLY bad mess as far as noise, so this shielding is having effect, but I wonder if it can be better. I was contemplating a lug to connect the control plate solidly to the foil shielding, but my meter cannot measure any difference in resistance between foil-->foil and plate-->foil.
 
#578
I'm having problems as well. I have Dimarzio Ultra Jazzes in my Jazz bass project and I get hum if I don't touch the strings. I shielded the control cavities. The white and black ground wires I've soldered and taped together, however I'm not exactly sure how to ground the shielding, I think that's what's making the bass hum. The bass sings when I play, I just get this hum when I don't so I'm pretty sure the soldering is fine. I'm not exactly sure how to install a lug or even have an idea what that is :(. This pictures isn't the clearest but I can get better one's if someone thinks they know a solution.

Thanks

IMG00982.jpg
 
#579
Hum if you're not touching the strings is not a shielding problem. That's a ground issue, and it could even have to do with the the amp you're plugged into and the place, maybe even the pickup design.

There are some cases where you can't totally get rid of all the hum.
 
#580
Vic said:
Hum if you're not touching the strings is not a shielding problem. That's a ground issue, and it could even have to do with the the amp you're plugged into and the place, maybe even the pickup design.

There are some cases where you can't totally get rid of all the hum.
Click to expand...

I thought so but I switched basses and my Fender MIM P was silent. I'm not exactly sure what to do, this hum is annoying me.
 

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