Noise hum g400

[Stewie]

I recently purchased a 2007 G400. This guitar is going to my vacation home and will stay there. I had a fret level and set up done and it plays like a dream. I am getting quite a bit of hum and crackling. I did a search and found other people have issues with grounding. The thing that throws me is that the noise actually gets louder when I touch the strings. All of my other Epis and Gibbies are dead quiet with the same amps so I know it is the G400. Is there anything that this symptom would point to. I really don't want to spend a lot of money on this issue and I would probably get rid of it before I replaced the electronics.

I know all about Epi pickup selector switches, but I have not had any other issues with my any Epi's pots or pickups.

I will take a look at the input jack and see if that is the culprit. Other than that any ideas would be appreciated.

[RaSTuS]

I recently purchased a 2007 G400. This guitar is going to my vacation home and will stay there. I had a fret level and set up done and it plays like a dream. I am getting quite a bit of hum and crackling. I did a search and found other people have issues with grounding. The thing that throws me is that the noise actually gets louder when I touch the strings. All of my other Epis and Gibbies are dead quiet with the same amps so I know it is the G400. Is there anything that this symptom would point to. I really don't want to spend a lot of money on this issue and I would probably get rid of it before I replaced the electronics.

I know all about Epi pickup selector switches, but I have not had any other issues with my any Epi's pots or pickups.

I will take a look at the input jack and see if that is the culprit. Other than that any ideas would be appreciated.

You'll have to at least take the control cavity cover off and do a rudimentary inspection, are any of the wires going to the jack frayed or loose, when you insert a plug does it make good contact with the matching parts of the jack, it may even interfere with the jack wiring, it could be many things but you'll have to check it out to know.

 

At a minimum you should invest in a can of contact cleaner and flush the pots and the switch, very easy to do and should only cost about $10.

[jerrymac]

I recently purchased a 2007 G400. This guitar is going to my vacation home and will stay there. I had a fret level and set up done and it plays like a dream. I am getting quite a bit of hum and crackling. I did a search and found other people have issues with grounding. The thing that throws me is that the noise actually gets louder when I touch the strings. All of my other Epis and Gibbies are dead quiet with the same amps so I know it is the G400. Is there anything that this symptom would point to. I really don't want to spend a lot of money on this issue and I would probably get rid of it before I replaced the electronics.

I know all about Epi pickup selector switches, but I have not had any other issues with my any Epi's pots or pickups.

I will take a look at the input jack and see if that is the culprit. Other than that any ideas would be appreciated.

 

You've got a ground problem. I would bet that you're bridge is going to hot instead of ground. That's why you're getting noise when you touch the strings.

 

 

You said you had a problem with the switch??? Did you replace it??? Did the noise start right after that??? If so, make sure you didn't switch the output wire with the ground.

 

All components should be grounded. If you don't have a volt meter to test continuity, and you should if you're working on guitar electronics, here's how to test the ground. Plug it in, turn on the amp. Touch all the metal components, pots, switch, jack, pickup covers, bridge, stop tailpiece... No noise or reduced noise indicates they're properly grounded (assuming they're working OK to begin with). If it hums when you touch it, it's a good bet it's reversed. If every component hums, the whole circuit is reversed.

[Stewie]

You've got a ground problem. I would bet that you're bridge is going to hot instead of ground. That's why you're getting noise when you touch the strings.

 

 

You said you had a problem with the switch??? Did you replace it??? Did the noise start right after that??? If so, make sure you didn't switch the output wire with the ground.

 

All components should be grounded. If you don't have a volt meter to test continuity, and you should if you're working on guitar electronics, here's how to test the ground. Plug it in, turn on the amp. Touch all the metal components, pots, switch, jack, pickup covers, bridge, stop tailpiece... No noise or reduced noise indicates they're properly grounded (assuming they're working OK to begin with). If it hums when you touch it, it's a good bet it's reversed. If every component hums, the whole circuit is reversed.

thanks for that JerryMac. I might have misled you. I own, and have owned several Epi HB guitars. I have had trouble with the switch on 3 of them. This one seems to be working fine. I will check the grounds as you said and see where I am getting the noise.

The guitar was very lightly played when I bought it. It still had the plastic on the pickgaurd and back plate. So I am fairly certain it is stock wiring. I will check it out or have my tech take a look at it.

 

Udate: Fixed.

I took the back cover off and took a look at the wiring. After finding a couple of wiring diagrams and pictures of a G400 control cavity I was able to find the problem was with the jack. For those who don't know the grey wire (EPI) should be attached twice to the jack. The wire portion to one of the contacts and the wire coax wrap to the other which serves as the ground. In my case the coax connetion had been pulled off.

I guess most guys don't realize that when they tighten a loose jack plug, you have to hold the jack in a staionary position. If you allow the whole jack to rotate you stand a chance of breaking off one of the connections. That is what happened.

I don't have a soldering iron so I popped over to my local tech and he fixed in 2 mins and didn't charge me.

Now it is dead quiet and I am a happy camper.

I have owned a Gibson SG for over 40 years. It has been retired and I rarely play it. I really like the way the G400 plays and sounds. I haf forgotten how nice they are to play.

Thanks for the help guys.