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Ground noise problem

eric_B

eric_B

Apr 19, 2015
876
1,152
The Netherlands
#1
I have a 2 month old Squier VM Jazz Bass. Nice bass, but I have a hissing / buzzing sound, coming through my Fender Rumble combo but also when I plug directly into an audio interface into a PC.
It disappears when I touch the metal output jack on the bass. That's nice but not very practical as I need both hands to play bass...

I moved the amp to the other side of the house and tried an outlet which is on another RCD. The noise was almost completely gone. So I guess it probably isn't a problem with the bass but with noise on the electrical system.

I was thinking, would a power conditioner (like this Furman which advertises with noise filtration) do the trick? Anyone used one of these?
 
#3
The fact the noise stops when you touch metal/strings/bridge indicates the ground is fine but you are getting RF interference. If you give your bass a proper shielding job the noise will stop, it's a pretty easy fix. If you were having ground issues the noise would get louder when you touched metal/strings/bridge.

I hope that helps.

As far as the power conditioner goes, I wouldn't recommend an external solution to an internal problem. I would also suggest reading ONVI labs site about power conditioners.
 
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#8
If both pickups are up all the way, and the pickups themselves are not defective, then you shouldn't be getting pronounced 60 cycle hum, so yes, I'd look at the shielding next. If it is indeed shielded properly, I'd look at the other sources(house wiring, amp, etc). In my experience, "exposed pole" pickups aren't as quiet as fully shielded, "enclosed" type pickups.
 
#9
CentralCoastBass said:
If both pickups are up all the way, and the pickups themselves are not defective, then you shouldn't be getting pronounced 60 cycle hum, so yes, I'd look at the shielding next. If it is indeed shielded properly, I'd look at the other sources(house wiring, amp, etc). In my experience, "exposed pole" pickups aren't as quiet as fully shielded, "enclosed" type pickups.
Click to expand...
To be clear: it isn't a low hum but more of higher pitched buzzing / hissing sound.
I've also read the single coils are more noisy then humbuckers.

Still, if it is a shielding and not a ground problem, how come the noise disappears when I touch the metal jack with a finger?
I can understand touching the metal can change the ground connection but why would it make the RF/EMI disappear all of a sudden?
 
#14
BAG said:
The fact that the noise disappears when you touch the metal output jack but not (I assume from your OP) when touching the strings says that the ground connection from the jack to the bridge is not working. Either that or you are using tapewounds.
Click to expand...
Hey man, can I buy you a cigar? As a test I put a piece of wire between the bridge and the jack and the noise is gone! :thumbsup:

But then, what's next to do - and would it be normal for a 2 month old (new) bass to have this problem?
And how to fix it: can I screw off the bridge and check for a loose cable?
And do the same with the control plate containing the jack?
 
#15
Glad to hear that you seem to have isolated the problem, but I'm still curious as to why the problem occurs when you're plugged into one RCD but not the other. Can someone explain why this would be true if the problem is a ground connection inside the bass?
 
#16
Lobster11 said:
Glad to hear that you seem to have isolated the problem, but I'm still curious as to why the problem occurs when you're plugged into one RCD but not the other. Can someone explain why this would be true if the problem is a ground connection inside the bass?
Click to expand...
I was wondering about that as well. Maybe because on this RCD there is a lot more (RF) noise that is now flowing to the ground whereas on the other RCD there was hardly any so I couldn't hear it?
 
#17
eric_B said:
I was wondering about that as well. Maybe because on this RCD there is a lot more (RF) noise that is now flowing to the ground whereas on the other RCD there was hardly any so I couldn't hear it?
Click to expand...
We'll have to wait for someone more knowledgeable than I to answer this. Something I was thinking, though, was that maybe the difference isn't actually in the RCDs, but something else that's different on the other side of the house -- such as proximity to fluorescent lights or other potential noise sources. Of course, that still begs the question as to why altering the wiring inside the bass seems to solve the problem. I hope someone else can explain....
 
#18
On my passive basses and electric guitars, I find it handy when practicing and recording to use a cable with an extra wire about three feet long connected to the plug housing. The free end is bare for several inches, and, without providing unneeded detail, I tuck the bare end where it will be in contact with my skin. That eliminates the effect of that HF hash suddenly kicking in when I let go of the strings.

Otto
 
#19
eric_B said:
Hey man, can I buy you a cigar? As a test I put a piece of wire between the bridge and the jack and the noise is gone! :thumbsup:

But then, what's next to do - and would it be normal for a 2 month old (new) bass to have this problem?
And how to fix it: can I screw off the bridge and check for a loose cable?
And do the same with the control plate containing the jack?
Click to expand...

It isn't normal for a new bass to do this. If you can live without it for a short time i'd take it back for warranty repair.

If you want to do it yourself you can take off the bridge as you suggest. There should already be a wire that goes from the bridge somewhere to either the output jack or the back of one of the pots. This has either come away or has a dry joint in the soldering. There should also really be wires going from each pickup cavity to earth (pot or output jack) as well. These are usually screwed to the shielding paint and then go through to the pot or output jack. If you know even a little bit about wiring and soldering it should be easy, however if you screw it up you might void your warranty so i'd say take it back if that's not a hassle.
 
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