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Little problem

D

davehewitsonuk

Feb 24, 2003
15
0
www.finelines.cjb.net
#1
I have recently been experiencing a problem with my yamaha RBX270. When ever i am playing through my amp, and i touch anything metal on the bass such as strings tuners pots, it makes a buzzing sound.

also, when the volume pot is turned anywhere between zero and full, the noise is constantly buzzing.

thanks

Dave
 
#2
This is likely to be a few things.

Grounding. Have you removed the bridge recently? If you have, the wire that comes from the body isn't likely making good contact with it.

The next is it could be your pickups. I don't know much about buzzing pickups, but it could be a factor.

The third is your amp/power supply. I find that sometimes my bass buzzes, then sometime sits quiet, then at other times there is nothing at all!

I think that the wiring in your home can depend on the buzzing in your amp, again I don't know much about that either, sorry. Hopefully someone can fill us in! :)
 
#3
Sounds like grounding to me. If you're not comfortable rooting around and being able to identify a cracked solder joint or resolder a loose wire, take it to a dealer or someone who can work on it for you. Sometimes those buzzes are really simple to find and correct, and sometimes they're the most frustrating things in the world.
 
#7
Originally posted by AllodoX
first thing i always do when i get a new bass is disconnect the grounding wire that leads to the bridge.. i never really understood why they put it there, because removing it solves the buzz problem ( and decent pickups have internal shielding anyway )
Click to expand...

The key to this whole post is "i never really understood why they put it there".

I have had to repair the ground connection under the bridge on many basses to elimenate hum. If an instrument hums through the amp untill you touch the strings it is nearly always because the bridge is not properly grounded.

A few active pup instruments don't ground the bridge but they are the exception.


H.Snyder
 
#8
Originally posted by AllodoX
first thing i always do when i get a new bass is disconnect the grounding wire that leads to the bridge.. i never really understood why they put it there, because removing it solves the buzz problem ( and decent pickups have internal shielding anyway )
Click to expand...

May God have mercy on your soul should you come across a microphone, or other instrument amplifier that isn't phased with your equipment. In this situation, the ground lead would have shunted most of the circuit back to the amp and tripped a breaker (hopefully). Without it, touching your strings will lead to the current directly crossing your heart to ground and that could prove fatal. :( :rolleyes:
 
#11
Originally posted by Hambone
May God have mercy on your soul should you come across a microphone, or other instrument amplifier that isn't phased with your equipment. In this situation, the ground lead would have shunted most of the circuit back to the amp and tripped a breaker (hopefully). Without it, touching your strings will lead to the current directly crossing your heart to ground and that could prove fatal. :( :rolleyes:
Click to expand...

I'm sorry to bring this _old_ thread up. I did a search over grounding and found this piece of information that is WRONG. If there is no bridge ground, touching a charged object does no harm. Only if the strings are grounded (or you touch any other grounded part), a (possibly lethal :/ ) current flows through your body.

The reason why I did a search is that I removed the bridge ground when I installed EMGs (it is recommended in their instructions) and have now swithed to Dimarzios. I'm not having troubles with hum or other noises at the moment but I just want to make sure not to have such problems in the future. What is the bridge ground used for?
 
#12
Originally posted by TRU
I'm sorry to bring this _old_ thread up. I did a search over grounding and found this piece of information that is WRONG. If there is no bridge ground, touching a charged object does no harm. Only if the strings are grounded (or you touch any other grounded part), a (possibly lethal :/ ) current flows through your body.

The reason why I did a search is that I removed the bridge ground when I installed EMGs (it is recommended in their instructions) and have now swithed to Dimarzios. I'm not having troubles with hum or other noises at the moment but I just want to make sure not to have such problems in the future. What is the bridge ground used for?
Click to expand...

It is Tru that this has been an oft discussed topic but not necessarily here in TB's Setup forum. My advice on this is an opinion that I stole from the venerable Bill Bolton. Bill is a world recognized authority on the Fender bass and is an electrical design engineer. His final word on this argument was posted in "The Bottom Line" an email digest for bassists. The paragraph below appeared in 2000 in issue 365 for that year.

...The electrical safety principle is that exposed metal parts of
anything that is connected to a non-double insulated mains powered
piece of equipment (i.e. the amp), WHETHER OR NOT THE ITEM ITSELF IS
MAINS POWERED, should be grounded to a solid mains ground.

The problem that needs to be addressed are why there EVER could by any
equipment around with live exposed metal parts on it as a expected
semi-common occurrence, or any equipment which is not double insulated
that does not have a solid mains ground. The solution is to correct
those problems, either by eliminating the possibility of live metal
parts and no solid mains grounds, or at least mitigating the risk
exposure by correct use of GFIs and similar safety systems. Unless a
situation of double insulation applies, it is NEVER the correct
solution to disconnect grounds from other exposed metal parts just
because they may under some limited circumstances create a circuit to
ground.

However, I've told all of you once, twice and now three times. If
anyone wants to ignore sound electrical safety advice, well at least
I've reasonably attempted to carry out, to the best of my ability, the
ethical requirement levied on me by the professional engineering
associations to which I belong.

Cheers,

Bill


Bill Bolton
Sydney, Australia
Click to expand...

The entire discussion is lengthy and offers lots of interesting theory but the bottom line (oops:o) is that I'll have my grounds hooked up and functioning properly and I use GFI protected power cables exclusively. Ya'll do whatever!
 
#13
I often times practice in a basement that has faulty or non working 3 prong ground outlets. I know some are not properly grounded, because of the noise I get when playing there. PLus it is an older house.

Now if I get a GFI type of a plugin or strip to put into the wall will this help?? Does it need to be on the PA since I will touch a mic along with my bass amp?? What about pedals?
 
#14
The thing is that you can't get a GFI plug in or strip. This is a very special set of sockets that must be wired in a certain way to work properly. I built my own power extension with a GFI box at one end for my rig. That is enough to protect me alone. It would be a good idea to do the same with the PA - at the least it wouldn't hurt in any situation.
 

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