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Jazz Shielding Pictorial (Big Images Warning)

#741
#748
A note of caution when doing the shielding work. I used the stew mac foil on a jazz bass. Worked really well, easy to work with. However I ruined 2 pickups in the process, both of which I only figured out after the fact what had happened.

The edge of the shielding tape can be very sharp - sharp enough to cut the coil wires on the pickups as I discovered!
If you can somehow install the pickups without taking the covers off you'll be OK but IME there's always some tweaking to be done or it's a tight fit so you need to lift the covers off first. Use extreme caution when installing/uninstalling the pickups and make sure that the exposed coils don't get caught on the sharp edge of the shielding tape.
 
#749
Britbonic said:
A note of caution when doing the shielding work. I used the stew mac foil on a jazz bass. Worked really well, easy to work with. However I ruined 2 pickups in the process, both of which I only figured out after the fact what had happened.

The edge of the shielding tape can be very sharp - sharp enough to cut the coil wires on the pickups as I discovered!
If you can somehow install the pickups without taking the covers off you'll be OK but IME there's always some tweaking to be done or it's a tight fit so you need to lift the covers off first. Use extreme caution when installing/uninstalling the pickups and make sure that the exposed coils don't get caught on the sharp edge of the shielding tape.
Click to expand...
I've never had to install the uncovered pickup and then somehow install the cover. It's always been possible for me to install the pickup fully assembled, which is even the only option in many cases (some covers can't be removed).

Not sure why that couldn't work for you, but I've always found that if you do a really good job of cleaning the pickup routes of buffing residue and other stuff, and really pressing the shielding hard against the wall of the pickup cavity, the fully assembled pickup slides back in just as easily as if the shielding weren't there, and, there are no sharp exposed edges to deal with. Yeah, it takes a little more time/work, but IMHO it's well worth it. If you look at the pictures Lyle originally took, they're good examples of a nice clean and tight shield job.

FWIW anyway.
 
#751
selowitch said:
To achieve that, a burnishing tool like Invalid Link Removed really helps.
Click to expand...
True. Alternatively, any small dowel or round pen/pencil, chopstick, etc, does just fine, depending on the radius of the corner you're trying to press the foil into. Whatever works.
 
#752
Shielding is far more important than it was 'back in the day'. Now we have cell towers and wifi everywhere. This introduces RFI (radio pollution) to low voltage signals such as an axe. The basic solution is the Faraday Cage, which most shielding solutions emulate. The philosophy is to have a conductive room, with a connection to ground only. The thing to remember is that the lower the resistance to ground, the more effective the cage. I've found copper to be more effective than aluminum or paint. Paint shields very well, but the complication is continuing the low resistance path to ground. With copper, you can solder a wire to it, which is about as good as it gets. From there, you want to dump to ground as near to the end of the signal path as possible.

In the interest of full disclosure, I am not an electrical engineer. I live in a bowl of RFI soup, with a TV tower and a major train yard in view. I've been battling RFI for years.
 
#753
JoeWPgh said:
Shielding is far more important than it was 'back in the day'. Now we have cell towers and wifi everywhere. This introduces RFI (radio pollution) to low voltage signals such as an axe. The basic solution is the Faraday Cage, which most shielding solutions emulate. The philosophy is to have a conductive room, with a connection to ground only. The thing to remember is that the lower the resistance to ground, the more effective the cage. I've found copper to be more effective than aluminum or paint. Paint shields very well, but the complication is continuing the low resistance path to ground. With copper, you can solder a wire to it, which is about as good as it gets. From there, you want to dump to ground as near to the end of the signal path as possible.

In the interest of full disclosure, I am not an electrical engineer. I live in a bowl of RFI soup, with a TV tower and a major train yard in view. I've been battling RFI for years.
Click to expand...
I don't think the RFI landscape has really changed that much... at least not in the realm that affects this topic in a significant way.

I've had and dealt with these problems since at least the late 70's, and most of the towers we see polluting the landscape these days are cell towers, which operate at such high frequencies (I think microwave) that it doesn't really affect this stuff in a significant way.

Most of what we deal with is way down in the audio spectrum and usually RFI/EMI around the 50/60Hz power transmission/distribution stuff we've had for many years.
 
#755
So, I took a 1998 MIM Jazz as a reclamation project and here are some pics and notes regarding the shielding. pics of bass cavities and pickguard below...

Where i have differed from many is that 1. this is not a star ground, and 2. no soldering of the copper shield

a) Concept: a Faraday cage is an encompassing enclosure and so based upon this i have deviated significantly from methods used by others, in the respect that i have grounded as much as possible, wherever possible... so the control cavity allows grounding of the control plate at three locations, and the pickguard is grounded also at three locations.

b) the bridge pickup cavity: if you roll the copper tape such that the backing is on the outslde, you can put a tube down through the drill hole, protruding 1/4" from each end... then judicious use of an exacto knife (scalpel) allows you to slit the ends, tear off the backing and fan out the copper making a solid connection.

c) the bridge : i did the bridge first and ran a piece of 18awg (all i had) to a securing screw between the control and neck pickup cavity..this is an easy location to both drill and screw.... doing this again, i would simply follow the same process as for the bridge pickup cavity... ie..no wire is necessary.

d) this tape is good stuff.. do the bottoms, then the sides, layer it up as much as you like..the conductivity of the adhesive is excellent... and all points to all points was measured unregisterably low...

e) the pickguard: you only need to shield around the pickup, the entire pickguard is overkill

f) In passive mode,
i) no additional ground is required as the 1/4" jack is mounted to the grounded control plate, but if you really want, you can run a wire from the 1/4" ground to the ground screw
ii) pup grounds go to the ground screw.

I ran it like this for a couple of weeks before i plumped my $$ for the Audere pup.. with that, pups go to preamp and ground to the screw (again, not really necessary, but looks neat..lol)..


Results?.. i have an ancient house with bad wiring, limited grounds and so noise simply oozes out everywhere.. this, along with N3 noiseless pups and its the quietest thing in the house.


anyway, hopefully this helps and encourages someone to spend the $10 and shield their bass..

IMG_0337.jpg


IMG_0338.jpg
 
#756
Britbonic said:
A note of caution when doing the shielding work. I used the stew mac foil on a jazz bass. Worked really well, easy to work with. However I ruined 2 pickups in the process, both of which I only figured out after the fact what had happened.

The edge of the shielding tape can be very sharp - sharp enough to cut the coil wires on the pickups as I discovered!
If you can somehow install the pickups without taking the covers off you'll be OK but IME there's always some tweaking to be done or it's a tight fit so you need to lift the covers off first. Use extreme caution when installing/uninstalling the pickups and make sure that the exposed coils don't get caught on the sharp edge of the shielding tape.
Click to expand...

What are you doing? How are you putting the tape down so that there are any sharp edges at all? It seems to me that it would be difficult to have an exposed edge that's sharp enough or prominent enough to do any damage if you tried.

When I shielded my bass, I just used the back of my fingernail to flatten and press most of the tape, except in corners and recesses where I used a dental tool (a pencil eraser or popsicle stick would work just fine). I was just concerned with ensuring the tape would be permanent, and everything was flattened down nicely. It never even occurred to me that sharp copper tape edges might damage any electronics, because there were simply no edges exposed or protruding anywhere.

(I know you were talking about shielding the pickup routes, not the control cavity, but the same principle applies. And I don't have a picture of shielded empty pickup routes.)
BrozTone_zps5a35d94c.jpg



...and then he realizes he just responded to a post that's almost half a year old... :o
 
#759
selowitch said:
Beautiful work, BlueTalon. I'm afraid I lack the patience, skill, and fine-motor control necessary to attain that level of perfection. Well done!
Click to expand...

Thank you very much! But I think you underestimate yourself. This didn't require that much skill or fine motor-control. It just required a lot of patience and copper tape. To quote myself from another thread:

BlueTalon said:
I put a lot of time and attention to detail in that shielding (I even used dental tools to apply parts of it). And copper. I used a lot of it. I made sure everything was connected to everything. Underneath the bridge, there is a copper foundation that is almost exactly the width and length of the whole bridge, grounded to the control cavity. I even used copper tubing in the drilled channels between pickup routes and the control cavity.

Overkill, I know. But I figured if I was going to mess up anywhere, I was going to err on the side of bulletproof.

The nice thing about copper is you can solder it, which allowed me to be both thorough and creative. For example, I did the best I could to be sure the copper foil in the pickup routes was fully connected to the copper tubing between the routes. But just in case, I used a standard ground wire also, soldering both ends to the pickup and control cavities respectively. But I did it as inconspicuously as I could, and then I covered it with more foil. So from the control cavity, all shielding ground wires are completely invisible.
Click to expand...

To be fair to the poster I replied to earlier, I did take precautions against potential sharp edges -- but of the copper tubing, not of the copper foil. The precautions consisted of using heat-shrink around the pickup wires where they go through the drilled channels. I also de-burred the tubing itself before putting it in, so there should never be a problem.


BTW, for anyone who might have concerns about the shielding having an effect on the tone, here is a quote from Michael from Turnstyle Switch, who's doing my electronics for this build:

More good news. I got the neck on it and WHOA does this bass sound good!! These pickups not only sound amazing but work exceptionally well with the Turnstyle switch. Even if these were not noise canceling, they would be worth the price just on tone quality alone. The clarity of them reminds me of the Fralin pickups I have in my Tele.

The BrozTone setting with everything wide open is crazy sweet sounding. Reminiscent of the Seinfeld J-Bass tone but the middle pickup adds a whole new complexity to the tone without even the slightest hint of mud.
Click to expand...

Oh, in case anyone is interested, the bass has three Fender split-coil Super 55 J pickups, two neck + one bridge, spaced 2" apart.

Brozbass_zpsd2c4d3f0.jpg
 

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