ridiculous hum...is shielding the answer?

[chuk31]

Hey, I'm looking for way to cut out the ridiculous hum my bass/guitars put out. I think its an issue with grounding, because whenever I stand on an insulated surface and touch the strings it stops, but take my hands off and/or stand somewhere else and its back. What's the best way to fix this?
-Charlie

 

[fazil]

Is the 230/110V (EU or US) connector on which your amp is plugged in grounded ? Does it have a grounding pin, and if so, is it accually connect ??

 

[gvarko]

What kind of guitar and PU's?

It will help to determine the problem

 

[boingoman]

If you touch the strings and it stops you probably need to ground the bridge.
the bridge needs to be connected to ground on the output jack. There may already be a wire there that has come undone. If you take off the strings and bridge you should find a wire that goes into the body. A lot of times the wire is just laid under the bridge. It gets pushed into the wood of the body, which makes for a bad connection. Strip off about an inch of insulation, and reposition the wire. A lot of fixed bridges(like on a bass) are just about impossible to solder to. But you can tape it to the bridge with a piece of scotch tape so when you remount the bridge the contact stays solid.

if it stops you are golden.

At the other end take off the plate under the controls. You will see the other end of the wire, maybe going to the back of one of the control pots. If its a solid connection, try soldering it directly to the jack where the ground wire from the back of the pots is connected.

If you have single coil pickups,like on a strat, and a lot of volume/gain, and you stand close, it's going to hum a bit no matter what.

 

[Light]

If it stops when you touch the strings, then the bridge IS grounded. If the bridge was not grounded, it would not stop.

Some amount of hum is normal with any guitar with passive electronics. It will be worse with single coil pickups than with humbuckers, obviously.

Shielding the cavities may help, in fact, it will probably help. It is not a cure all, however. Give it a try, and if the problem is better, then great. If it still needs work, look at the electronics (in fact, do this first). Do all of the connections look good? If so, then it becomes had to figure out the problem. I would try shielding it, and if it is still a problem, you need to talk to a good repair person. They should be able to figure out the problem.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[Dani Pace]

You are not alone

Just thought I'd let you know that at some point most of us have encountered a similar problem. In fact right now I am trying to solve a "ridiculous hum" on a 700 ST Kramer bass myself. As you and others have suggested there seems to be some sort of grounding problem, and sometimes those are hard to spot. I have discovered that sometimes a cold solder joint will be the culprit causing hum, perhaps someone at the factory was in a bit of a hurry and did'nt get one connection quite right. All the soldered connections should appear bright and shinny, if not get out the iron and reheat the points of contact. This may sound simple and silly but I have found a weak connection to cause a bad hum more than once. I hope you find the source soon, I know a hum can drive you nuts.