Loud hum with humbuckers.

Thundergod

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I don't know if this is the right place to post this, if it's not please move it where it belongs.

I'm experiencing loud hum on one of my guitars, it's loaded with railhammer chisel pickups from the factory and there was no hum or noise for over 6 years. Out of nowhere it started humming worse than my strat and tele.
Other guitars with humbuckers won't do the same in the same place, outlet, amp, cable.

When touching any metal the hum disappears. But it's really annoying when my hands aren't touching the guitar.

Bridge is wired to ground. Pots are grounded. Haven't really checked with a multimeter as I'm no longer sure of what to look for with one on this subject, I did check with it to see if there any ground connection that isn't properly soldered, seems they are ok.

So I changed the pots. Same result. Wired the pickups directly to the Jack... Same result.

Does anyone have an idea of what to do next? There's no real guitar tech where I live, I used to do all of this (for my guitars and for other's guitars) but it's been years since I did, and due to some other things that happened I don't really remember how to do a lot guitar related stuff, I'm lucky to be playing again.
 

Shred Astaire

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Dude!! I don't have an answer but holy shit. How are you doing bud?
 

Dolebludger

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I too wish you well! But I must admit to being a poor guitar tech, and hope you get more expert replies. But from my amateur standpoint, it seems that you have eliminated all the usual causes, except the pups and/or the wiring directly to them.
 

sonar1

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Is it possible a coil has partially shorted out due to corrosion?
How does it sound?
Any sudden lower output from the suspect pickup?
 

Thundergod

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Is it possible a coil has partially shorted out due to corrosion?
How does it sound?
Any sudden lower output from the suspect pickup?
They sound as loud as ever. And there's no noticeable corrosion on the outside of any of the pickups.
The issue is with both pickups, either by themselves or while using both at the same time.
 

sonar1

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They sound as loud as ever. And there's no noticeable corrosion on the outside of any of the pickups.
The issue is with both pickups, either by themselves or while using both at the same time.
Sounds like somewhere a ground has lost its connection.
Look for a cold solder joint inside. May have degraded over time to finally get to be a problem.
Probe around with the guitar plugged in. Check the output jack carefully
 

KSG_Standard

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I don't know if this is the right place to post this, if it's not please move it where it belongs.

I'm experiencing loud hum on one of my guitars, it's loaded with railhammer chisel pickups from the factory and there was no hum or noise for over 6 years. Out of nowhere it started humming worse than my strat and tele.
Other guitars with humbuckers won't do the same in the same place, outlet, amp, cable.

When touching any metal the hum disappears. But it's really annoying when my hands aren't touching the guitar.

Bridge is wired to ground. Pots are grounded. Haven't really checked with a multimeter as I'm no longer sure of what to look for with one on this subject, I did check with it to see if there any ground connection that isn't properly soldered, seems they are ok.

So I changed the pots. Same result. Wired the pickups directly to the Jack... Same result.

Does anyone have an idea of what to do next? There's no real guitar tech where I live, I used to do all of this (for my guitars and for other's guitars) but it's been years since I did, and due to some other things that happened I don't really remember how to do a lot guitar related stuff, I'm lucky to be playing again.
Can't help you Thunder, but it's good to see you're still alive and kicking!
 

Dolebludger

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This is probably a stupid reply, but have you tried a different guitar cable? If that provides no fix, the problem is likely between the pots and the pups. How about the pup selector switch, and the wiring and connections to the switch from the pots and from the switch to the pups — and/or the switch itself?
 
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six-string

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a lot of guitars ground to the bridge or tailpiece. if the wire that runs there, from the pickups or pots or switch is loose or shorted this could explain the loud hum. the strings act like antenna picking up noise, but when you touch them, you become the ground.
if other obvious stuff like the jack, switch etc are not the culprit, this may be the issue.
good luck. View attachment 513431
 
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Uncle Vinnie

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Does it stop or diminish when the volume knob is at 9 or 10, or does the noise persist all the way from 1-10?
 

el84ster

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This is easy:
There is no ground until you become the ground (you touch the strings) so get out your meter, set it to resistance (fraction of an ohm will indicate continuity) or the continuity beep if you have that on your meter and see what should be grounded but isn’t.
Check against the ground of your output jack.

Something that was grounded is not any more. Reconnect and you’re good.
 

Dolebludger

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I am seriosly interseted in this problem, as too live where good guitar techs are scarce (even before the pandemic). And there was a time between 2000 and 2009 when I didn't play for a number of rasons. When I tried to play again, I plugged int my Mesa Boogie Mark III and it sounded like I was abusing everybody from an entire country. I got another cable and it sounded as good as it can for me playing through a Mea Mk III, which I know know is not good. Clearly, you have a grounding issue, but where? I wish I knew!
 

Thundergod

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Sounds like somewhere a ground has lost its connection.
Look for a cold solder joint inside. May have degraded over time to finally get to be a problem.
Probe around with the guitar plugged in. Check the output jack carefully
This is probably a stupid reply, but have you tried a different guitar cable? If that provides no fix, the problem is likely between the pots and the pups. How about the pup selector switch, and the wiring and connections to the switch from the pots and from the switch to the pups — and/or the switch itself?
I tried with different cables. Same result. Also other humbuckers guitars don't do the same with the exact same setup.
 

el84ster

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Back when I just started working on stuff I had the same problem. I didn’t know how to hunt it down, so I simply added an extra ground wire to everything that needed to be grounded. Lol.

you can also solve this with a jumper wire with alligator clips. Again, something was grounded and isn’t anymore. Just find where it’s not and you’re gold.
 


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