Earthing?

[dyker124]

Hi All,

I have this noise problem. It is interference picked up by the guitar(s). There is a constant noise in the background which sounds a bit like fluorescent light interference, although I do not have any fluorescent lights. If I move the guitar around it disappears or gets louder depending on where I move it to. If I very lightly touch or stroke the strings I get this crackling sound through the output monitor speaker. If I turn the guitar volume control down, the noise reduces with it until volume at 0, noise is completely gone. It appears to be pickup by the guitar. I do operate quite close to my equipment (about 4 feet away). The amplifier speaker is not active as I am connected directly to my digital recorder. I do have a speaker monitor though plugged into the headphone socket of the recorder. I thought it could be an earthing problem. To this end I've checked out my earths........ I do not have any.

1) Amplifier - Roland Cube 30X fitted with 2 core mains lead.

2) Yamaha MagicStomp - Adapter with no connection between earth pin and either of the + and - output connections.

3) Line 6 Pod HD - Adapter with no connection between earth pin and either of the + and - output connections.

4) MICRO BR Recorder - Adapter with no connection between earth pin and either of the + and - output connections.

Is this a normal state of affairs with everyone else out there, or do I have to introduce an earth into my line-up somewhere?

Kind regards
Roger

[hernando]

Looks as if you have no earth on this set-up. Ideally this should be as close to the source as possible, so try connecting the guitar earth to the nearest real earth.

Use a length of wire with something like a crocodile clip on each end, and clip one end (on a strat) to the bridge or the guitar lead jack socket plate.

Clip or connect the other end to a nearby known earth - such a a hot water radiator or the "earth" in a three pin plug.

If the interference goes away - you have an earthing problem with your set up!
Good luck

Dave

[dyker124]

Hi Dave,

Many thanks, I'll give it a try.

Kind regards
Roger

[bazmusicman]

Surely the amplifier should have a three core lead with earth to be safe?
Baz.

[dyker124]

Hi Baz,

You would think so wouldn't you. But no. The Roland Cube 30X which I purchased new about 3 years ago is fitted with two core mains cable. I think it comes under the 'double insulated' category. I was always led to believe that 'all' metalwork that comes into contact with a person should be properly earthed (ie the ground of jack plugs/sockets, guitar strings/bridge, etc). I wonder how many other amplifiers out there now have two core mains leads fitted.

[geoff1711]

Hi All

the amp being solid state, probably works on quite a low voltage, so probably has a power supply insulated from the main board, and as such probably doesn't need an earth to conform to EU legislation.

Most of my guitars are fitted with noiseless pickups, because when played at home, which is where they mostly are played, things like computers, dimmer switches, fluorescent light sources, transformers etc all create a background hum which single coil pickups pick up.

I did have one scratchplate which crackled when I strummed, it was generating static, I changed it and the problem went away.

Geoff

[dyker124]

Hi Geoff,

I think you are right. I have an amplifier which as you say is low voltage so the metalwork is floating from earth. Plus four add-ons which all have adaptors which are also floating from earth. So my whole kit is floating. No wonder when I touch my guitar strings or bridge/tremolo arm there's a sizzle/crackle.

I wonder if most peoples kit are like this?

Also, I wonder if it would be in order for me to replace the amplifier 2 core mains cable with a 3 core to earth the metal parts (I am a retired electronics design engineer)?

[barryk]

Hi Roger

It should be perfectly ok to replace the two-core mains cable with a three-core one to provide earthing. As you are an electronics engineer I hope I don't need to tell you that the new cable and plug fuse need to be of appropriate rating and the cable anchored properly in a cord-grip at the amp end. Also the unsheathed live and neutral cores of the new cable inside the amp must have additional insulation sleeving added if they could come into contact with internal wiring on the low voltage side of the power supply. Preferably fit heat-shrink sleeving over the solder joints and use a shake-proof 'star' washer agaist the metal on the new earth bolt and double washer and nut it with the new earth wire tag between the two washers and nuts.
Your own safety and that of others is paramount, since you would be liable if anyone was injured as a result of your failure to carry out the work to a sufficiently high standard. I have to state this in case anyone else reading this attempts a similar modification and doesn't understand what is required to do the job properly.

Regards to all

Barry

[dyker124]

Hi Barry,

No problem at all. I fully understand the involvement and the reason for the detailed explanation.

Many thanks.

Kind regards
Roger