tech question!

[yoroichi]

Greetings bass wizards,i am not sure if this is the right thread (if not sry!)

I have a problem with my fender Duff mckagan signature bass that
has a Precision and a jazz magnet

Now the jazz magnet makes some noise which im told is natural
but i get feedback noise even from my precision magnet on certain gear arrangments (when i get my bass through a console or something)

the other problem that i have is that i tried my bass with a band
on a specific amp(which has no problem because this issue has troubled me before with other amps) on a rehersal homestudio and at the same sound settings for the amplifier, another bass sounded 3 times louder than mine.

My teacher told me i have some problem with the bass's grounding.

Any thoughts?


thank you in advance : ]

 

[khutch]

The STK-J2B pickup (we say pickup, not magnet) that Fender claims to use for the Jazz pickup in that bass is supposed to be hum canceling. Single coil Jazz pickups are susceptible to hum when used alone so what you are told is true, but only for single coil pickups. The pickup you have should cancel out the hum, it is a dual coil pickup in a Jazz pickup housing. Since the P pickup is also giving you noise it could indeed be a grounding issue you are having. Another possibility is that your bass needs better shielding, there are many threads here that discuss that. Does the noise you get come and go if you hold the strings or touch the bridge?

I don't know if the volume difference is something to be concerned about or not. A bass with hot humbucking pickups or one with an active preamp cranked to boost-boost-boost will sound louder than a passive bass. So what you hear could be normal or an indication that something is wrong. Is there a Fender dealer or a guitar shop with a good technician near you that could look the bass over for you?

Ken

 

[yoroichi]

The hum is much louder when i am not holding the strings

I plan on bringing it to the nearest fender technician

but my problem is that i dont know if i can describe the issue well enough
so that they can fix it.

in the past (bout a year ago) i gave it to a technician and asked him to check the grounding and he said it was fine,he probably didnt even take a look at it.

 

[khutch]

Unless they let you watch them work it is hard to say if a tech did anything on a problem like this, only that if they did do something it was not effective. There is supposed to be a ground wire from somewhere in the control cavity to the bridge. Often times the ground wire just pops up through a hole under the bridge and the end of it is stripped in the hope that it will make contact with the bridge as you tighten the bridge screws and pinch it between the body and the bridge. You should be able to check that connection with an Ohmmeter. You could also strip both ends of a short piece of wire and use it to short the bridge to the output jack ground while listening to the noise. If the noise goes away or the Ohmmeter says that connection is open you may fix or at least help the noise problem by making a good connection.

Noise that changes as you touch or release the strings could indicate that the connection is open but other things could be an issue too. This could be a system problem rather than just a bass problem. My bass is dead quiet at home but when I play through my church's sound system I get a buzz when the volume is turned up and I don't touch the strings. I think my bridge ground is good but I am making a mental note to check that on my basses when I get home. We have a rotating collection of sound/tech people at church and last Sunday the senior guy was there. At one point during the pre-service warm up he walked up on stage and punched a switch on the DI box my bass connects through. That did improve the buzz although it did not go completely away. I did not have time then or later to ask him what he did but I suspect that it was a ground "lift" or "phasing" switch that he hit. In this case the buzz is not loud enough to be a problem when we are playing so I try to remember to hold the strings when I am not playing and to turn the volume all the way down when I put the bass in the stand and leave my position.

Ken