Not another HUM Question

[spunko]

Hello, I'm Daniel and I have HUM   I know theres a lot of things that can cause it, but this is my case.

I have a Les Paul with Seymour Duncan Alnico II, and everytime I'm not touching the strings, or any other metallic part of the guitar, it makes hum when distrotion or overdrive is added; in clean doesn't hum much unless I set the volume of the amp at 70% or louder.
Now, the guitar has a wire that grounds the bridge with one volume pot, and I tested for continuity in random places of the guitar, and it looks fine, but I didn't tested all ground points of the guitar. I don't think it needs to be shielded becuase it has humbukers.
On the other hand, is the wall outlet, this thing is old! so old that it doesn't have the third slot, the round one or ground. I took it out of the wall and there are two wires, line and neutral, but no ground. I also noticed that line and neutral where inverted, but fixed that.

Do you think the lack of ground in the wall outlet is making the hum when I'm not touching the strings?
What would you recommend?

Sorry for my english.
Thank you.

[spunko]

bump! 

[bluebunny]

Do you think the lack of ground in the wall outlet is making the hum when I'm not touching the strings?

Yep.

What would you recommend?

Add a ground connection!     Be careful: get someone qualified to do this if you're not 100% confident.  Messing with mains wiring can kill you (or others).  We don't want that: you've only just joined us.  

BTW, welcome, Daniel!

[spunko]

thank you very much!
Well I was thinking in a copper bar, like 4 feet long, burried into the ground, outside my house, and conect it to the chasis of the amp.
Will that work?

Just for the fun, I tied a cable from the chasis of my amp, to the chasis of my air conditioner, which is 220V so i think is in another connection, hoping not to get any ground loop from another appliances in 220v line. (I haven't take out this wall outlet, so I cant tell if my a/c is grounded). It was the same, if I dont touch a metalic part of the guitar, the humm is there. Also tryed it with a metalic door, same.

[bluebunny]

Unless you live in Outbackistan, I would hope that your AC wall outlets do have some kind of earth connection.  Seriously, get the amp mains rewired so that it has an earth conductor too.

[Stinger]

had the same problem in past, and I can assure you the ground connection can easily solve at least 60% of your hum issue.
Proper guitar shield should help as well, even if you have humbuckers.

[Thecomedian]

I bought a 200w amp from Guitar Center, and it turned out someone had cut off the ground tip for the plug. Exact same problem. Had to replace the plug and now 100% improved.

I know they're not electricians, but I can't believe they don't have some sort of safety assurance types that go around stores and check sold-back product or at least tell the workers that if they notice anything electrical that looks damaged, to immediately prevent it from being sold.