Hum buzz that goes when touching strings.

skunkwerx

Sorry, I can’t remember what the deal with that issue is, whether its normal or a grounding issue. 

I have a cheapy Ibanez gio with humbuckers, and its volume pot became loose. So I took the plastic knob off, tightened and accidentally overtightened the nut, buggared it or the thread but got it tight enough to stay in place. 

In the meantime I may have knocked the volume pot about in the back of the cavity. It was turning round as I was tightening the nut on the topside, lols.
Amateur hour aside, I finished my but butchery. 

Anyway when plugged in to le amp with gain, there is buzzing which does get quieter when I touch the strings. 

Hell it could have been like that before, but as I noticed it after I fcked with it, I’m now convinced I’ve made matters worse and somehow messed with the grounding of the guitar.

So final question, if it sounds like the grounding or wiring needs to be checked, is it safe to play in the meantime, or is a bad ground dangerous? 

I plug into my pedalboard, powered by a zuma, into a katana.
I did notice if I touch a metal chassis of a pedal or the metal jack connectors on the end of a patch cable, or the zumas metal casing, the buzz subsides as it does when I touch the strings of the guitar. 

Fanx all! 

ICBM

It’s normal, but if the noise seems worse than before it’s possible that you’ve disturbed the connection between the volume pot and the cavity shielding, so it’s now unshielded - that will increase noise when not touching the strings.

A bad ground in a guitar is never dangerous, it’s actually the opposite! The danger is from a bad ground in an *amp* leading to the guitar ground becoming the ground path - via you.

gringopig

.

Rabs

Lots of stuff can cause buzzing..  PC fans, fridge motors, dimmer switches, fluorescent lights...  All sorts of stuff...

Some people find shielding the cavities helps a bit.

With a grounding issue often when you touch the strings it gets worse. By touching the strings and it getting better it at least shows that your bridge has a ground wire.

If you had single coils it would be way worse (even though I love my P90s).

pintspiller

Washing machines going into "spin" we're a curse in one of my houses

prowla

Well, the whole question of ground is an interesting one.

A (passive) guitar is the signal generator which connects to the input of the amp/pedals; the signal a guitar generates is very low and there should never be high voltage there.

However, there is an assumption that the overall ground is a fixed thing, which may not be true.

If you plug two items into different mains sockets, their ground may not be exactly the same and you can sometimes see a spark if you plug things together; this is why you should not daisy-chain extension leads and so-on (it applies to offices, the house, bands, etc.).

Earth loops can cause humming and buzzing, but that is a different thing to the buzzing/hum from a guitar.

Years ago I was playing in a band in a club and the singer came over and put his arm around me, at which point there was a bang and the lights went out. The PA was plugged into one mains and the backline into another. Ever since then, I touch my guitar to the mic before doing anything else.

So, when things are working right, there should be no risk, but it's a good idea to be aware of failure scenarios; in a normal setup, the guitar's ground is connected right through to the earth pin of the mains socket and we all take the integrity of that on trust.

I think the only way to prevent the above scenario is to use wireless.

But, as has been noted, a good/bad/intermittent ground in the guitar's internal wiring will make no difference.

Bridgehouse

pintspiller said:

Washing machines going into "spin" we're a curse in one of my houses

And ceiling fans still are in mine

ICBM

prowla said:

However, there is an assumption that the overall ground is a fixed thing, which may not be true.

If you plug two items into different mains sockets, their ground may not be exactly the same and you can sometimes see a spark if you plug things together; this is why you should not daisy-chain extension leads and so-on (it applies to offices, the house, bands, etc.).

No - the first part of that is correct, and hence the last part is wrong - it’s safer to daisy-chain extensions than to use separate wall sockets. If you daisy-chain, you ensure that there is only one single ground connection. It’s often not possible to do that on a big stage though.

prowla said:

Years ago I was playing in a band in a club and the singer came over and put his arm around me, at which point there was a bang and the lights went out. The PA was plugged into one mains and the backline into another. Ever since then, I touch my guitar to the mic before doing anything else.

That is almost always the most dangerous combination - because the mixing desk (where the mics are connected to via the multicore) is usually at the other end of the room from the stage and so can sometimes be on a different ring main.

The surprising thing to most people is that what makes it so dangerous is the guitar being grounded - because it completes the circuit from the live circuit to the earthed circuit via you. Contrary to popular belief, guitar grounding is not for safety, it’s to reduce noise, and it would be safer for them not to be.

Also, it makes no difference if you use an RCD on your gear, because the earth remains connected. An RCD will stop a fault with the supply to your own amp killing you, but not from another source.

I had a similar shock when I was setting a band up once - between a guitar and a bass with amps plugged in on opposite sides of the stage... I held the bass while the bass player did something and got a shock from it to my guitar which my other hand was resting on. Since then I always remove the direct string ground connection on my instruments by fitting a high-voltage cap in line - that maintains the shielding while preventing shocks, at least from the strings. (The jack and other metal parts are still a risk.)

But don’t worry *too* much - modern electrical regulations are much tighter than they were and it should be very rare to find a venue with this sort of hazard now.