B.C. Rich Bass Still Hum

fedesmiro

fedesmiro

Oct 4, 2018
2
0
4,551
29
Italy
#1
Hi Everyone!
A friend of mine gave me a bass that has the hot cable disconnected to the output jack, a piece of cake, fixed it very quickly. But after that, I noticed that there's the typical 60Hz hum that comes out so I started debugging but didn't find the solution. The strange thing is that my friend said that before that hum was not there.
The bass has 2 humbuckers, it's a Warlock Model. The cavity is shielded with conductive paint. I checked out that there were no ground Loops, all soldering are shiny and ok. checked out all continuities ( to the bridge too).
If I touch metal things of the bass connected to the ground, the hum reduces but is still here.
If I close the tone pot fully, the hum is rejected.
( I'm not playing near a TV or a dimmer Light etc..)
So I start thinking that the problem is the pickup himself, and so I connected the neck pickup bypassing all the volume and the tone circuitry directly to the output jack ( including the bridge ground) and the hum is still there. I really don' t know what I can do to solve this out.
 
#2
If touching strings quiets it, then better shielding will help.
That conductive paint is just bare minimum, IME copper shielding tape does a better job.

Maybe your friend just didn't notice the noise, because either his environment doesn't have as much EMI or he had the treble cut pot rolled back.
 
#4
About a month ago I put a small strip of copper foil shielding tape from the cavity shielding on a G&L L-2000 to the lip of the controls cavity, so it would make connection with the foil on the cavity cover.
It made a significant difference in the noise level, compared to before when there was no connection between the shielding paint & the cover.
 
#5
Any other audio issues with that exact outlet in your wall? I only ask because in my current apartment, I can plug into one outlet and get unquenchable buzzing like that, but the next outlet a few feet over is dead quiet. Different basses can be more or less sensitive to this. I would also say that pickups going bad does happen, had a DiMarzio Area P literally die (stopped putting out signal) that was installed and nothing was done to it for over a year. Tried swapping out the wiring, but it was just the pickup that had died.
 
#6
Since I'm using my instruments in my Bedroom/Laboratory (lol) I tried switching off multiple devices and tried other instruments, and then after many trials, I ended up thinking the problem is the pickup from many reasons:
-I got the noise from the bass directly into the spectrum analyzer of my MOTU, it's very easy to determine that the frequency of the noise is 60Hz. Switching supplies and Wi-fi and RF work's frequencies are much higher than that.
-When I play my guitars I hear no hum at all. My Schecter has a Conductive paint as shielding too (it has humbuckers). My Fender has single coils and no humming (it has aluminium shielding). But I know shielding protects from high frequencies, and humbuckers should help in hum rejection.
- I just tried to bypass the tone and volume circuitry, as mentioned before, so I think is not a bad joint/ground loop Issue

Thanks in advance to all guys :)
 
You must log in or register to reply here.
Top Bottom
Back