A shielding question....

[DaveB]

I was playing my Axis Sport (2 Hum) tonight and was working on the intro to "Just take my heart" by Mr Big. It has a harmonics section where I end up taking both hands off the guitar. When I did this I got horrendous buzzing and clicky tapping noises when I next touch anything. Simple I thought it must need some shielding work - so I opened up the back and absolutely everything I imagined had been done. The electronics are on a plate, the cavity is painted with shielding paint, the back of the cover is foil lined - and there is even a contact wire for when you put the plate back on. So why does it still buzz?

The guitar is many years old, second hand and in the UK - before I get hassle for not phoning customer service

Yours in confusion

Dave

 

[PeteDuBaldo]

Are you using lots of gain, or have a TV/computer monitor on causing interference? I've noticed similar problems when I have my TV on and am playing.

Also, it could be a grounding issue between the guitar/amp, do you have a ground lift switch you can flip? Not sure how electrical stuff works across the pond.

 

[kbaim]

Not the one you bought from me I hope.

 

[DaveB]

No it was an Axis Sport not the one I got from you....
I play it both high and low gain and my main screen is LCD so no probs from that In effect...

Dave

 

[koogie2k]

Maybe Mr. Horsepower senses you are abandoning her or cheating on her and has thrown the 4 pick up voodoo on ya! heheheheheehe......

Does the wiring seem in order...no loose connections?

 

[beej]

Sounds normal to me- even the best shielded guitar is going to pick up some hum when you're not touching the ground. And it sounded properly grounded, 'cause it goes quiet when you touch the strings.

 

[tommyindelaware]

Sounds normal to me- even the best shielded guitar is going to pick up some hum when you're not touching the ground. And it sounded properly grounded, 'cause it goes quiet when you touch the strings.

+1.....
it's behaving normally.......
the fact that it is quiet when u r touching it indicates a good ground.


is there an echo in here ????????

 

[Tim O'Sullivan]

This is what I would normally expect from my guitars. I wouldnt worry about it too much personally.

 

[nobozos]

Check out this link.

Lot's of good information on this site. This guy has his own theory on your issue, and I can say with my background in electronics that it all seems plausible.

http://www.guitarnuts.com/technical/noisebucket.php

Check out the rest of the site, it's very good.

 

[beej]

Yeah- in general that's a good site! Though, I don't agree that all grounds have to be star grounded- that's overkill and shouldn't matter inside a fully shielded guitar (faraday cage).

 

[nobozos]

I don't want to get all tech-geek on everybody, but there is no way to fully shield a guitar without the grounding. Even if you completely isolate all the electronic components in the guitar, you still have 6 metal strings acting as an antenna for any kind of stray noise in the air. Unless you ground the strings to every other component in the guitar, you will have problems. All components should be grounded together to remove any possibility of stray grounds.

 

[beej]

Right- but they are here (the strings are connected to the bridge which is wired to the same ground as all the components and the cavity), so it's all good.

Sorry if I was misleading in my comment- what I meant was that there doesn't need to be a single grounding point inside the cavity (the star wiring as mentioned on that site); multiple grounds are just fine and don't pose a problem.

 

[nobozos]

That's true, as long as all the grounds go back to the jack ground. All grounds must eventually lead to the jack ground, but I agree, the configuration of the grounds is relatively unimportant. Star grounds, series grounds, parallel grounds, it doesn't matter, ground is ground, but like in Highlander, "There can be only one."

 

[NorM]

So Let me see if I understand this. When you stop playing or take your hands off the guitar it makes sounds you don't like?
Just keep playing then.

Two computer monitors and the PA rack causes this to happen at Casa De NorM.

 

[beej]

Or just solder your hands to the strings

 

[favolos80]

Sounds normal to me- even the best shielded guitar is going to pick up some hum when you're not touching the ground. And it sounded properly grounded, 'cause it goes quiet when you touch the strings.

A question:why my ibanez universe doesn't make any hum when i'm not touching the strings?

 

[Spudmurphy]

Or just solder your hands to the strings

...and wear a chain that touches the floor!!

 

[brentrocks]

It is interesting that somebody brought that up! Because my guitars do it sometimes and sometimes not!

It may have to do with the fact that I play through a wireless? But sometimes i can take my hand off the guitar...no humm!

I'm on carpet too, i dont know if that makes a difference??

I think the Aliens are F*****G w/ us!!!

 

[beej]

A question:why my ibanez universe doesn't make any hum when i'm not touching the strings?

Guitar strings act like an antenna - picking up stray interference from all the electromagnetic fields around you. This is reduced significantly when you ground the strings by touching them.

Why does this happen more on one guitar than another? There are various factors that can affect it (pickup output, etc.), but suffice it to say that this is normal behaviour. If the guitar is quiet when you're touching the strings then you're good to go.

 

[Adwex]

+1.....
it's behaving normally.......
the fact that it is quiet when u r touching it indicates a good ground.


is there an echo in here ????????

+2. If shielding were the problem, you'd hear the buzzing regardless of touching or not touching the strings.