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I have a couple of archtops that seem more susceptible to noise than others. They have humbucking (Armstrong hand wound) pickups, quality pots, reasonably good grounds. Yet, sometimes it's clear that unless I'm touching the strings (acting as an antenna I think) I can get hum out of them at an annoying level. Don't have motors or fluorescent lighting and most guitars are well behaved. Have not isolated an external noise source. I used standard wiring for the internals (not shielded but twisted with ground wire). One has thumbwheels and one has regular pots. Using short cable runs to amp. I don't think there are bad solder joints but certainly possible. Hate to tear into them for a rework just to see but going to have to replace the output jack on one anyway so could take a look at other things while I have it on the bench.
So.. how do you diminish noise? If this were a Strat I could line the cavity with copper tape and ground it. Thinking this is probably just whack-a-mole until changing something makes it go away but thought I would see if there is some wisdom on this topic.
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11-05-2023 05:30 PM
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I thought the touching strings thing means it’s grounding issue? Something is not wired correctly
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Sometimes. According to a good ohm meter everything is as it should be in terms of connections. Also a bad connection would be all the time and not just sometimes? That and wiring for a pickup, single volume, and single tone isn't too hard to inspect. I also tried adding a ground jumper to the tailpiece just to check and it didn't change things.
Originally Posted by RyanM
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I just turn the volume knob down when I’m not playing.
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Ground loop maybe?
If your strings are grounded as they should you could always run a cable from the jack connector or tailpiece to your skin so you're always touching the strings
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So there is continuity from the pickup cover to the strings? Originally Posted by Spook410
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There are plenty of YT vids where well-known professional players are interviewed, their humbucker-equipped guitars in hand, and you can clearly hear the buzz when they’re not playing but did not roll the guitar volume down. Archtops are just as prone to this as any other electric guitar. My two Japan-made Ibanez guitars have shielding around the pots and components which is clearly visible through the f-hole. They’re dead-quiet. No matter what. Not even crickets, just silence. Others, including my PRS and Gibson Custom guitars, buzz much more. Assuming there are no faults in the wiring, a good shielding job (Faraday cage) will solve it.
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It sounds like a grounding problem of some sort. The fact that the buzz goes away when you touch the strings is a classic sign of the strings not being grounded. Metal tailpiece or wood? Is there a ground wire to the tailpiece?
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No pickup cover on an Armstrong hand wound. Ohm meter shows 7K (ish? can't recall actual value) across pickup with solid grounds. Originally Posted by sgosnell
Also..
Have a ground lift available. No change to guitar noise.
It sounds like a grounding issue at each guitar and I'll work that over some more. Possibly I need to scrape some paint of ground contact for metal tailpiece (which is a pretty good chunk of metal).
It changes. Better sometimes. Worse others. One guitar is worse than the other. No issues on most guitars including single coils.
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With no cover, you would need to measure from the bottom of the pickup. But it is probably enough to measure from the ground side of the output jack to the strings, which won't require removing the pickup. Each string should be grounded, it's sometimes possible for only some strings to be grounded, depending on the tailpiece and the strings.
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Not meant to insult with the following question, just trying to eliminate possible causes: are you playing the guitars always through the same amp?
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I had this on my archtop. Wrestled with it for probably 15+ years- replacing pickups, pots, caps, etc., multiple times. Several times I looked as best I could at the wiring to double check which conductor was to the tip and the ring, peering through one F hole while shining a flashlight in through the other. I installed a string ground under the wooden tail piece. I shielded the underside of the pickguard with copper tape. Just about pulled my hair out. A Kent Armstrong PAF-0 was the worst offender, even worse than my CC Rider from Pete Biltoft. The least noisy solution was a "monkey on a stick" pick up (Kent WC-16) that I tried for a little while. Drove me nuts and I avoided playing the guitar through an amp for several years.
Finally one evening I took a photo through the F hole with my phone and blew it up. I noticed that the Mogami wire to the jack did not have the insulation stripped at the ground point to the jack (a tailpin jack, it has a little arm that clamps down on the wire to ground the shield; the conductors are soldered to the sleeve and tip terminals separately). The wiring diagram from the jack manufacturer showed the insulation being stripped at that point. I pulled out the jack, stripped the insulation for about 3/16", squeezed down the clamp onto the shielding and reinstalled.
Problem solved. Without the shield being grounded, the insulation was acting as an antenna and inducing hum in the conductors. Basically, the luthier just overlooked that one little detail back in 2006 and it was the only thing in the circuit I had never thought to check.
If you are using a shielded wire from the controls to the jack, it's worth double checking.
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I have a lot of trouble with end pin jacks. Not sure why. Using switchcraft components etc. Going to revisit the basics on how well it's installed.
From the comments seems most that have experienced this have found it to be some flavor of grounding issue so going to proceed down that rabbit hole. Hopefully it will take less than 15 years as I really like this particular guitar.
As always.. appreciate the informed comments.
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I grounded the strings on a Washburn J600k by running a wire under the tailpiece from the metal rib that holds the string balls to the end jack. Cured my hum.
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The following is about electric hum as opposed to the magnetic hum from single coils.
The guitar body is slightly conductive, being wood with a certain moisture content and it picks up a hum voltage, mainly from the player who picks it up from the mains wiring etc. Grounding the strings grounds the player who touches the strings.
Because the guitar body is live with hum, there is a hum electric field that penetrates a short distance inside it. This field will transfer hum to any nearby unshielded part of the wiring. The most likely candidates are the wide blades of a pickup switch and the jack socket.
Shielding these or, alternatively, putting copper tape connected to the nominal ground on the inside of the guitar to isolate them usually solves the hum problem. I have tried this and it worked perfectly, making a noisy guitar completely hum free.
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Wood is not a conductor... nor is pure H20.. Originally Posted by aquin43
Putting shielding around things is a good idea to prevent external RF noise from entering the audio signal path.
However the logic about hum fields is incorrect.
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Yea... this is always a problem. At least years ago. So I've always redone all soldering, wire and grounding issues myself and also use copper tape shielding , even under pick guard.
When was in different recording studios... tape days.... I always would hear the tick or extra noise etc..
Also changed most of my pickups to Bartolinis and problems were gone... silence.
I'm not an expert... but could never find an expert that could fix the problem.
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The word "slightly" is of significance here. We are talking about a system with a fairly high hum voltage and very small capacitive coupling between the guitar body and the point of entry of the hum. The impedances involved are many megohms. I have considered the alternative explanation of direct injection of the hum from the player with the guitar as a passive dielectric separating the player from the point of injection but it doesn't seem able to explain the detailed behaviour that I have observed. Originally Posted by SoftwareGuy
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Kiln dried wood is an insulator. It has a low end resistant of 100 trillion ohms per meter and goes up from there. Originally Posted by aquin43
Go try and measure the resistant of a popsicle stick and see how far you get.
I will not reply further.
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Aero instruments sells a device to solve this problem. It was reviewed in GP.
Basically, it connects the ground on the guitar to the player's skin in a way that it says enhances safety. It's called dBuz.
I recall reading something to the effect that your body is the antenna and touching the guitar (with intact string grouding) then grounds your body. But, if you're nearby the guitar without touching it, the guitar's electronics may sense whatever is coursing through your body-antenna and amplify it. Heard then as hum.
I have no idea if this is right, butit's free and easy to check. Get the hum and walk away from the guitar. Does it subside?
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Old thread, but sometimes I find old threads in searches and they have an answer I'm looking for, so thought I would update this.
The primary source of my noise problems was a poor connection between the guitar 1/4" cable and the guitar input jack. It didn't sound like a poor connection. It sounded like a poor ground allowing things like RF interference that goes away when you touch the strings. However.. it was the connection.
I have several guitars with acoustic style barrel jacks that poke out where you would typically find an end pin. Typical setup for flat tops. On an archtop it comes through a hole in tailpiece bracket. There can be both some extra wood there for bracing (at least appears to be on these guitars) which is hard to get at if you want the barrel jack to come out farther and you have have the thickness of the tailpiece metal. This can lead to the barrel connector being a little inset. That and a guitar strap can offer some problems to getting a solid connection. Once I got rid of as much of the barrel jack inset as possible and got a good solid connection for the 1/4" plug, the problems with noise went away completely.Last edited by Spook410; 04-06-2024 at 04:17 AM.
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No , I’ve just fixed a loud intermittent buzz problem in myAlso a bad connection would be all the time and not just sometimes?
Ibanez Af120 that i’ve has off and on
for years ….
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It turned out to be a semi loose earth
connection to the can of the Vol pot
activated by the wiring moving tiny tiny amounts ….
(i used to ‘cure’ this buzz by gently
thumping the guitar with the heel of my hand)
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good to know …. Originally Posted by Spook410
glad you sorted it ,
it’s great when you fix a longstanding
problem innit ?
I just fixed one of mine that was
driving me crazy
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