Incorrectly installed "shielding" can act as an antenna. But then it isn't shielding, it's an antenna.
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Why does a JMJ buzz but not a P bass?
- Thread starter socknroll1
- Start date
Exactly.
The “shielding can cause problems” statement is like putting new tires on a car, not tightening the lug nuts, and then blaming the tires when they fall off.
Also important to note, all cavities must be connected to ground. So, either all cavities are connected then one wire to the electronics ground, or each individual cavity connected to electronics ground. If an area is covered in shielding material, but not grounded, it is not a shield, it's copper wrapping paper.
DiabolusInMusic
Functionless Art is Merely Tolerated Vandalism
Like everyone else said, the noise that stops when you touch metal/strings/bridge indicates RF interference that requires shielding to resolve. If it was grounding, the noise would get louder with touch. Your techs must be old to be anti-shielding. You don't have to go too far back in time to a world that thought shielding was pointless. Most of that old guard is gone though, even Fender shields all their instruments these days.
A shop charging two+ hours labour on a tape job isn't unreasonable. That being said, I don't know why a professional wouldn't charge an hour and do it with paint. You first tape job will probably take a couple hours since you're learning. I can do a bass with paint in under an hour.
If you decide to do paint, the choice is paint matters greatly. Make sure you are buying quality material from a reliable place. Stew-Mac shielding paint is overpriced trash.
Shielding is an easily accomplished task with a few tools and some time. Check out the link in my sig for basically everything I know on the subject.
Just be aware, foil tape is so sharp it would give a razor blade a run for it's money, ask me how i know.
This is not an uncommon issue with the JMJs - I shielded mine in an hour or two and it fixed the issue. It's very easy!
The roll I bought on Amazon was thankfully not sharp on the edges. It is a soft foil. This might have made for an uglier job because it creases and tears easily, but I've never been cut working with it.
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Yeah, there are several MIM basses they don't do any shielding on, and it might be the period-correct thing like how the JMJ is mimicking a 60s Mustang. But it's the only necessary mod I'd make to a JMJ.
I want to return here to say (1) thank you to all you chimed in and (2) I'm still not comfortable doing it myself. Respectfully, I can carefully apply tape, but when we get to words like solder, properly grounded, test the polarity, test the connectivity, &c., I really feel that even with the guide someone kindly posted, I do not have any confidence in doing it right myself, which defeats the purpose. You're telling me it's "very easy", but also linking to a very long guide, and telling me that if not properly grounded, there would be no effect at all. If I can't properly do that last, crucial step, then I don't feel it's worth me attempting at all.
I am asking 1 more shop about it. If they will do it for a reasonable fee, I will let them.
I will ask 2 handy guitar players about it, too. If they are willing, I could ask them to do it for a fee.
In the meantime, I will play 2-3 more gigs with it.
If none of that works, and especially if it's noisy at the gigs, I am going to re-sell it.
I think another takeaway for me is, all instruments can have a bit of a hum, some more than others, even with split-coil pickups. Best to consider that with any purchase.
I am asking 1 more shop about it. If they will do it for a reasonable fee, I will let them.
I will ask 2 handy guitar players about it, too. If they are willing, I could ask them to do it for a fee.
In the meantime, I will play 2-3 more gigs with it.
If none of that works, and especially if it's noisy at the gigs, I am going to re-sell it.
I think another takeaway for me is, all instruments can have a bit of a hum, some more than others, even with split-coil pickups. Best to consider that with any purchase.
I am absolutely PERPLEXED that it's even a question about finding a shop that can do it. Hope you don't sell it on account of some shielding!
If I was close I'd do it for a cheap bottle of whiskey and some attention from your dog or cat. That's how easy it is. No soldering or electrical testing is required.
If I was close I'd do it for a cheap bottle of whiskey and some attention from your dog or cat. That's how easy it is. No soldering or electrical testing is required.
This is what I used (at Amazon, Elk brand) but there are others; the important thing is that the adhesive backing is conductive. That way, you can overlap pieces (more on that later)
A Faraday cage is a container made of conductive material that intercepts and diverts electromagnetic fields. For practical purposes, this means you can shield things against stray signals getting in (causing interference) or getting out (causing interference in other things).
When we line the electronics cavities of an electric guitar or bass with copper foil or shielding paint, stray signals will hit the shield, be converted to a small electric current, and be diverted to ground, so it doesn’t mix with the desired signal from your instrument’s pickups.
Copper foil tape is essentially like thin metal masking tape. It’s quite easy to do; you cut pieces to fit the largest surfaces inside your electronics cavity, and then smaller ones to fill in the gaps to form a continuous shield.
Now, if only the cavity was shielded, you might still be leaving a big space for stray signals to get in. To close the “cage,” the foil in the cavity needs to make contact with foil on the back of your pickguard, or on the back of your control cavity cover for instruments with rear-routed controls (like Ibanezes).
Usually this can be done by leaving one or more “tabs” to create contact between the shielded areas when everything is put back together.
Finally, the shield needs to be connected to the grounding lug on your instrument’s output jack. This can be as simple as using a small lug screwed into the wood, and soldering a wire between them, or connecting to existing ground points (typically, soldered to the back of a pot, etc.)
It’s also important that your bridge / strings are grounded. Under your bass’ bridge should be a thin ground wire, that leads to your control cavity. If that’s not connected, it can lead to noise when you aren’t touching the strings (and it’s a potential shock hazard).
All that to say - it may sound a little daunting but there’s plenty of videos showing how to do this, and lots of diagrams and beginner guides you can follow. Soldering requires a little patience and practice, but being able to do these things on your own will give you a nice sense of achievement!
Good luck —
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I would say they may not be set up to deal with shielding paint, because it requires a lot of PPE and ventilation - at least the good stuff does. I got a small container of MG SuperShield paint to do the pickup cavities on my SR and as it contains *serious* solvents, it was pretty intense! not something to do indoors, they recommend working outside and let it dry there overnight.
It’s definitely faster, but it’s probably a headache for small shops that don’t have the space to do it correctly or safely. For most people DIYing at home, copper foil is slower, but safer.
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Shielding paint doesn’t have to be sprayed, and nowadays it’s mostly water based so toxicity is way reduced.
DiabolusInMusic
Functionless Art is Merely Tolerated Vandalism
I have sprayed MG Chemicals many times in the garage. No different than other aerosols in terms of PPE, just a respirator. Also, you are not spraying nearly as much as a typical paint job. Dries in minutes. Can easily do 2-3 coats in under an hour.
But yeah, all the techs I know just buy the brush-on can of it. It can easily be applied in any shop. Never heard of anybody taking it outside to air dry.
DiabolusInMusic
Functionless Art is Merely Tolerated Vandalism
Honestly, if you get two-sided conductive tape, you could just tape the connection down. That being said, I would strongly recommend a quick dab of solder over tape. Probably the easiest solder job you could do.
Testing the connectivity is easily done with an ohm (or multi) meter. Just press the prongs into two points, see if it is an open lead or a resistance.
That all being said, I totally respect your reluctance to start the project. Hope you can get it all sorted. Odds are if it is noisy at home, it will be awful under stage lighting.
Good luck with the bass!
Hey all, another update for anyone curious. I'm reselling the bass but not really because of the hum.
The hum was bad at a practice space but nice and clean at 3 venues, so in a small sample size, I guess it's fine.
However, the tone of the bass is not what I want. Similar to some other short-scales I've owned, it doesn't have a lot of the high frequencies, even with the tone knob all the way up and EQ boosted on the amp. No harm done; my Junior Collection Jazz Bass has plenty of highs.
If it doesn't sell locally soon, you may see it listed here!
The hum was bad at a practice space but nice and clean at 3 venues, so in a small sample size, I guess it's fine.
However, the tone of the bass is not what I want. Similar to some other short-scales I've owned, it doesn't have a lot of the high frequencies, even with the tone knob all the way up and EQ boosted on the amp. No harm done; my Junior Collection Jazz Bass has plenty of highs.
If it doesn't sell locally soon, you may see it listed here!
